Strategies to grow the value of New Zealand’s fine-wool sheep industry - Ferguson MB; Rutherford S; Hamilton N; Hargadon M; Trompf JP (Proceedings of the New Zealand Society of Animal Production, 2014)
The New Zealand Merino Company Limited is leading a programme to create new opportunities and value for New Zealand’s sheep industry by transitioning growers to finer-wool genotypes and enhancing productivity on current and future fine-wool farms. This paper describes the approaches being undertaken to effect these changes and in doing so grow the value of the fine-wool sheep industry of New Zealand. A strategy has been developed that is focussed on changing the knowledge, attitude, skills and aspirations of producers and their key influencers. The strategy has a range of activities that can be grouped into the broad areas of development, awareness, recruitment and engagement. Importantly the on-farm strategy is matched with significant investment in careful product differentiation and improvement of the flow of information and value through the supply chain.

Summer lamb production and grazing management of pure swards of plantain (Plantago lanceolata) - Kemp PD; Kenyon PR; Morris ST; Johnston T; Appleton H; Best HK (Proceedings of the New Zealand Society of Animal Production, 2014)
Plantain is a productive and persistent pasture species known for its capacity to feed livestock over summer, but there has been limited research published on grazing management and lamb production from Tonic plantain in summer without irrigation. Farmlet scale (individual plots ranged from 0.44 – 0.75 ha over the three years), randomised and replicated experiments, with grazing lambs on pure swards of Tonic plantain were undertaken over three summers. The treatments were sward height at pre- and post-grazing and stocking rate. Study one was in a wet summer and the plantain was not water-stressed, whereas in study two, it was mainly dry and the plantain was regularly under stress, and in study three, the summer rainfall was erratic, resulting in a period of water stress at the beginning of the experiment. The average daily weight gains (ADG) of the lambs ranged from 81 to 219 g/day across the three studies. The highest ADGs were when soil moisture was not limiting plantain growth and post-grazing sward height was greater than 5 cm (approximately 1500 kg DM/ha). The crude protein concentration of plantain was low (156 -175 g/kg DM) when plants were water stressed and high (236 g/kg DM) when rainfall was adequate. It was concluded ADG of lambs grazing Tonic plantain in summer was greatest when pre- and post-grazing sward heights were 8 and 5 cm, respectively (2000 and 1500 kg DM/ha herbage mass) and the plantain was not water stressed. It is recommended that Tonic plantain be sown with pasture legumes to increase its feeding value and crude protein concentration.

Supply and demand for lactose in the New Zealand dairy industry - Sneddon NW; Lopez-Villalobos N; Hickson RE; Shalloo L; Garrick DJ; Geary U (Proceedings of the New Zealand Society of Animal Production, 2014)
Global milk product demand has been rapidly growing in the past decade, which is reflected in an increased demand for milk powders. The New Zealand dairy industry is capitalising on this by shifting its product portfolio towards milk powders. However, current international product specifications in combination with New Zealand milk composition and an industry objective to maximise farm profitability makes the industry deficient in milk lactose. This study aimed to determine how lactose deficit or surplus is influenced by changes in the product portfolio. In order to quantify this lactose balance, a computer simulation model was used (Moorepark Processing Sector Model). The 2012 New Zealand milk production (19.129 billion litres, milkfat concentration (4.99%), protein concentration (3.82%) and lactose concentration (4.70%, anhydrate)) was used within the analysis. Four manufacturing portfolio scenarios were investigated with different proportions of milk diverted to whole milk powder production (80%, 60% (current proportion), 30% and 10%). The model simulated the total production of whole milk powder, skim milk powder, casein, whey powder, buttermilk powder, butter and cheese. Whole milk powder production varied from 2,292,000 tonnes for the 80% scenario to 286,000 tonnes for the 10% scenario. Lactose mass balance varied from 214,000 tonnes in deficit for the 80% scenario to 510,000 tonnes in surplus for the 10% scenario. These analyses indicate that as more whole milk powder is produced, milk from current New Zealand cows results in an increased deficit of milk lactose. The national breeding objective could be adjusted to reflect changes in the future product portfolios to better align the composition of milk with the likely product mix.

What farmers will need from scientists over the next 20 years under a resource-capped environment - Barton MD (Proceedings of the New Zealand Society of Animal Production, 2014)
Farmers in the Lake Taupo catchment are operating under a Waikato Regional Council consent to farm that limits the amount of nitrogen that can be leached below the root zone. The main driver for nitrogen leaching is stock urine, effectively capping livestock numbers. This challenges current farm business models of intensifying stock numbers in response to rising costs. This paper outlines lessons from on-farm nitrogen-leaching trials carried out by AgResearch and Landcare Research. Farming in the Lake Taupo catchment will only be viable if consumers pay a premium for beef produced in a manner that protects the water quality of Lake Taupo sufficient to offset the increased costs of production. While this has been shown to be practical in the local area it may not apply in other areas of New Zealand or overseas. This raises a series of science priorities to support viable farming. Also discussed are the science needs indicated by the Lake Taupo Protection Trust formed to facilitate the removal of 20% of nitrogen leaching from farmed land. Currently science has provided no alternative permanent solutions other than removing farms from the catchment

Another look at shearing lambs - Scobie DR; Marshall AJ; van Koten C (Proceedings of the New Zealand Society of Animal Production, 2013)
Some farmers believe shearing lambs improves weight gain. On four separate farms, lambs were randomly drafted into two groups in summer, one was shorn while the other was crutched but left unshorn. They were subsequently run as one mob until all were shorn as yearlings in spring. Corriedale lambs (n = 100 x 2 years and 50 per treatment in a third year) were used on one farm, Halfbred lambs (n = 100 per treatment x 1 year) on another farm and two farms used Merino lambs (n = 50 per treatment on each farm x 1 year). Averaged across three consecutive years, the Corriedales shorn as lambs were 2.8 kg heavier as yearlings (P <0.001) and grew 629g more wool (P <0.001), which could be profitable. Halfbred yearlings shorn as lambs were 0.85 kg heavier (P = 0.041) and although not significant, grew more wool (120 g). Shorn Merino lambs produced 140 g more wool on one farm (P = 0.019) only, with no significant live weight differences between shearing treatments on either farm. International literature suggests the decision to shear lambs should be based on availability of feed, cost of shearing, time of year, temperature and the riskof flystrike, grass seed damage or adverse weather.

Association of the KRT33A (formerly KRT1.2) gene with live-weight and wool characteristics in yearing Perendale sheep - Sumner RMW; Forrest RHJ; Zhou H; Henderson HV; Hickford JGH (Proceedings of the New Zealand Society of Animal Production, 2013)
DNA samples from 691 mixed-sex Perendale sheep, born between 1998 and 2001, were typed for variation in the KRT33A gene using polymerasechain reaction - single-strand conformational polymorphism. The sheep were the progeny of two linesselected for either decreased (L), or increased (H) core bulk at yearling shearing, crosses between the lines and back-crosses. Five variants (A–E) of KRT33Awere identified with a frequency of 0.07, 0.04, 0.07, 0.35 and 0.47, respectively. The proportion of Adecreased and Bincreased, with a progressive increase incrimp frequency, fibre curvature and core bulk and a progressive decrease infleece weight, staple length and washing yield with each step-wise increase in the proportion of genes derived fromthe H line. An effect of the presence of Aon the measured wool characteristics was found, but was less than the effect with direct selection for core bulk. There was no consistent effect on body growth. While none of the variants of KRT33Awere strongly predictive of variation in core bulk, other genes on Chromosome 11 may be implicated in the differential expression of characteristics associated withcore bulk.

Association of variation in the ovine ADRB3 gene with weaning weight and post-weaning growth in New Zealand Suffolk sheep - Yang G; Forrest RHJ; Zhou H; Fang Q; Hickford JGH (Proceedings of the New Zealand Society of Animal Production, 2013)
β3-adrenergic receptors (ADRB3s) are mediators of the lipolytic and thermogenic effects of catecholamine levels in brown and white adipose tissue. Studies have linked variation within the β3-adrenergic receptor gene (ADRB3) to metabolic disease and obesity in humans (NCBI OMIM No. 109691), variation in loin eye muscle area in pigs (Hirose et al. 2009) and with dairy form in cattle (Connor et al. 2006).

Behaviour of New Zealand pasture-based cows offered access to free stalls fitted with sand or water beds, compared with cows at pasture - Lau J; Margerison JK; Hedley MJ; Horne DJ; Hanly JA; Powell N; Shilton AN (Proceedings of the New Zealand Society of Animal Production, 2013)
New Zealand dairy cows have typically been  grazed on pasture all year round, however intensification of milk production systems has led to increased nitrogen loss into the environment (de Klein & Ledgard 2001; Luo et al. 2007). Limiting the amount of time that cows have access to pasture, particulalry during inclement weather, by the use of feed pads or cow housing for parts of the season or day (de Klein 2001), can reduce nitrogen loss into waterways (Christensen et al. 2012). This approch is particularly important in protecting the soil and pasture from treading damage (Arnold 2009) and can allow non-lactating cows to be retained on the dairy unit over the winter or animals to be sheltered from excessive rain, cold and sunshine. Unfortunately, many New Zealand dairy farmers and the majority of cows have little or no experience of cow housing. This experiment was completed to assess the acceptance and use of differing free stall bed types by adult dairy cows, with no previous experience of housing, and to compare this with cows kept at pasture. The evening and nightly, daytime grazing and overall daily behaviour patterns of these cows are reported and discussed in this brief comunication.

Can milk urea nitrogen differentiate nitrogen use efficiency of lactating cow groups raised on New Zealand pasture - Aizimu W; Hodge S; Edwards GR; Dewhurst RJ; Cheng L (Proceedings of the New Zealand Society of Animal Production, 2013)
Improving nitrogen use efficiency (NUE) (g of milk nitrogen output/g of nitrogen intake) of dairy cows helps to maximise profitability and minimise nitrogen losses on farm. However, the traditional nitrogen balance technique used indoors to measure dry matter intake (DMI) and NUE is labour intensive, costly and unsuited to pasture-based grazing systems. In The Netherlands, milk urea nitrogen (MUN) has been used as a non-invasive and easy-to-conduct test to differentiate NUE of dairy cow groups (Kuipers et al. 1999). Generally, higher values of MUN are associated with a lower NUE. However, the usefulness of MUN in New Zealand pasture-based grazing systems is uncertain for numerous reasons. Firstly, MUN excretion reaches a maximum when dietary crude protein (CP) exceeds 20% of feed dry matter (DM), reducing the sensitivity of MUN to differentiate NUE in high dietary CP systems (Reynolds & Kristensen 2008). Secondly, water intake has been identified as one of the factors influencing the concentration of MUN, but it is not normally quantified in grazing systems (De Campeneere et al. 2006). Lastly, when individual cow samples are used, MUN may be subject to diurnal variation (Cheng et al. 2010).

Can weighing multiple times increase the accuracy of live weight recording? - Galwey JM; Logan CM; Greer AW (Proceedings of the New Zealand Society of Animal Production, 2013)
The recording of live weight in livestock enterprises is fundamental for breeding and production, the ease of which has been greatly improved with the advent of automated weighing and recording platforms. However, the extent to which significant advances within a livestock enterprise can be made with the utilization of live weight data depends on the validity of the indicated weights which can be influenced by measurement error from a number of sources (Hughes 1976). Thus, the use of scales only provides an estimate of an animal’s true live weight. Despite the importance of live weight, there is a distinct paucity of published data surrounding the variation in live weight estimates and weighing protocols that may be used to reduce this variation.

The changing nature of farm system research - Clark DA (Proceedings of the New Zealand Society of Animal Production, 2013)
A personal review of the contribution of farm systems research to New Zealand pastoral agriculture. Case studies have been selected from the author’s experience in sheep, dairy beef and dairy cow research over the past 40 years. These are used to emphasise the importance of progress in agricultural science and of wider societal concerns. The change in emphasis over time for farm systems research, from animal production per se, to production and profit, and now to production, profit and environmental protection is highlighted. Examples are also given of the value of thinking in a systems context in order to maximise the value of investment in basic and applied agricultural research.

Comparing herd selection strategies fo A2 beta-casein - Mencarini IR; Woodford KB; Old KM (Proceedings of the New Zealand Society of Animal Production, 2013)
Herd conversion strategies for A2 beta-casein were investigated within an inter-temporal simulation model with annual time-steps comprising three sub-herds based on allele status (A1A1, A1A2, and A2A2). Cows that are homozygous for the A2 allele of the beta-casein gene are known as A2 cows (A2A2), and produce milk known commercially as ‘A2 milk’. The simplest herd conversion process is to use semen from A2A2 bulls. However, the conversionfunction is curvilinear and asymptotic and this strategy by itself cannot achieve herd purity. Conversion rates can be increased markedly through genotyping of calves and/or cows. This is necessary for completion of the conversion process. Mating of yearlings with A2 semen can have considerable impact, particularly in association with increased replacement rates. Combining these strategies can lead to pure A2A2 herds within 5 to 8 years, depending on initial herd structure. Use of sex-selected semen can further reduce the conversion period. There is potential for reduced cow herd gain in breeding worth as a result of non-use of elite bulls that are not A2A2. For example, a loss of 20 breeding worth units in the bull team would result in ten years being required to achieve breeding worth gains otherwise achievable in nine years.

A comparison of aspects of the reproductive success of ewe lambs and mixed age ewes joined over the same period - Corner RA; Blair HT; Morris ST; Kenyon PR (Proceedings of the New Zealand Society of Animal Production, 2013)
Ewe lamb breeding at 7 to 8 months of age in extensive production systems, such as utilised in New Zealand, has a number of advantages including higher net profit from lamb production, improved utilisation of spring herbage, improved ewe lifetime performance and improved reproductive rate throughout the flock (Kenyon et al. 2012). However, in comparison to mature ewes there are limitations to ewe lamb breeding which include a lower lambing percentage, lower lamb birth weight  and lower lamb survival (Annett & Carson 2006; Kenyon 2012).

Comparison of castrate and entire ram-lambs for meat quality and skatole in the fat - Schreurs NM (Proceedings of the New Zealand Society of Animal Production, 2013)
Ram lambs are favoured in sheep production systems for their faster growth rates compared to ewe, castrate and cryptorchid lambs (Fisher et al.2010). The meat from ram lambs has been associated with poorer tenderness and colour characteristics when compared to the meat from ewe lambs of the same breed (Johnson et al. 2005; Craigie et al. 2012) but, the results across studies are inconsistent with some studies reporting no difference in meat quality between the sexes (Navajas et al. 2008, Kerslake et al. 2012). In a study by Rousset-Akrim et al. (1997), seven-month old male lambs had undesirable meat quality characteristics compared to three-month old male lambs suggesting that age of the lambs and the attainment of puberty are likely to influence the meat quality when comparing between sex classes.

Comparison of mating start date definitions for New Zealand dairy farms - Creagh FE; Sanders K; McNaughton LR (Proceedings of the New Zealand Society of Animal Production, 2013)
If the mating start date (MSD) is incorrectly established through database monitoring, then several reproductive measures will also be incorrect in a seasonal calving dairy herd. The definition currently used by the InCalf Fertility Focus report is the first day withartificial breeding (AB) record(s) within a sequence of four of seven days with artificial breeding (AB) records (Method A). The objective was to compare this with alternative definitions to reduce the occasional incidence of incorrect MSD that have been encountered in these reports. The alternative definitions testedwere two consecutive and four out of seven days (Method B), one percent (Method C) and three consecutive days (Method D). The National Dairy Database was used to test these alternate definitions. Among 963 herds with less than 150 cows, the current definition of MSD was the most appropriate. Among 7,004 herds with greater than or equal to 150 cows, visual assessment indicated that a new definition was more accurate. This was that MSD be set as the first of two consecutive days when followed with four of the next seven days having recorded AB matings.

Cows becoming clinically lame differ in changes in behaviour and physiology compared to cows that do not become clinically lame - Kamphuis C; Burke JK; Jago JG (Proceedings of the New Zealand Society of Animal Production, 2013)
The hypothesis that sensors can detect changes in behaviours and physiologiesassociated with cows becoming clinically lame was tested by comparing trends of sensor data from lame cows with non-lame cows. Sensor data included data from live weighing scales, pedometers (average steps per hour) and milk meters collected between November 2010 and June 2012 on five Waikato dairy farms. Farmers were trained in detecting and diagnosing lame cows. For each lameness event (n = 318 events affecting 292 cows) a time period of 14 days prior to the day ofdetection was randomly matched by farm and date to 10 non-lame cows. In this period, lame cows decreased in weight, steps taken per hour, milk yield in the first two minutes of milking, total milk yield, and milking duration. Lame cows also entered the milking platform later. In comparison, non-lame cows had no change in sensor data trends. These differences (P <0.05) in sensor data trends imply potential value of sensor data in detecting lameness automatically. Large variations in sensor data values between and within lame and non-lame cows indicated that future research should focus on combinations of variables that show the best potential to detect lameness automatically.

A cross-sectional survey of New Zealand sport horse stud farms - George HEA; Bolwell CF; Rogers CW; Gee EK (Proceedings of the New Zealand Society of Animal Production, 2013)
An online survey was sent to 74 sport horse owners. With a response rate of 45% (33/74) data were available from 33 owners of 74 sport horse stallions. Most stallion owners were female (29/33; 88%), aged between 35 and54 years (25/33; 76%), and had equine occupations (17/33; 52%). Most sport horse stud farms were not operated as the primary income source for the owner (27/33; 82%). Farms had a median of 2 (Interquartile range (IQR) 1–3) stallions and a median of5 (IQR 2–9) mares. There were four larger farms standing stallions that also provided frozen semen from stallions resident outside of New Zealand. Most stallions were privately owned (69/75; 92%) and 47% (35/74) of stallions originated from overseas. Half the stallions had their own performance record (36/75; 49%). Natural service was offered for 64% (47/74) of the stallions, 81% (60/74) of stallions were available via artifical insemination with fresh or cooled semen, and 37% (27/74) were available via artifical insemination with frozen semen. The number of mares covered by the stallions per season was heavily left skewed with a median of 5 (IQR 1–8). There were a small group of active sires (n = 7) that covered larger books of mares with a median of 42 (IQR 22–50).

Development of ultrasound methodology to measure cow udder cistern storage capacity in the New Zealand pasture-fed context - Molenaar A; Leath SR; Caja G; Henderson HV; Cameron C; Challies M; Taukiri K; Chikazhe T; Kaumoana S; Lannou B; Dorleac A; Guy A; et al. (Proceedings of the New Zealand Society of Animal Production, 2013)
Studies have demonstrated that, for a given amount of secretory tissue, cows with a proportionally larger cistern produce more milk and are more resistant to the inhibitory effects on milk synthesis of longer milking intervals (Knight & Dewhurst 1994; Stelwagen & Knight 1997; Davis et al. 1998). This may be because they can store more milk before milk accumulation begins to inhibit further milk synthesis. Ayadi et al. (2003) demonstrated in a feedlot situation that cisternal volumes can be measured non-invasively using ultrasound technology. Dairy systems based on pasture, such as those in New Zealand, exhibit different challenges to the production of useful data using this technology compared to feed lot systems and the confounding effect of the variability in milking order and the subsequent variations of the intervals between subsequent milking (Molenaar et al. 2012).

Does Production Worth and Breeding Worth reflect cow profitability? - Clark BJ; Garcia-Muniz JG; Black PJ; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2013)
Production worth (PW) is an economic index estimating the efficiency that a cow converts feed into farm profit. Breeding worth (BW) is another economic index that estimates a cow's or sire’s ability to breed profitable replacements. This study evaluates how well PW and BW are correlated with net income (NI) per 4.5 tonnes (t) of dry matter (DM) consumed on a pasture based New Zealand dairy farm. During the 2009/10 season at Massey Number 4 Dairy Farm, cow milk yield and composition were determined at monthly herd tests, and live weight data was automatically collected twice daily using a walk-over-weigh system. The results show that this herd is achieving a genetic gain of $6.74 BW per year. Correlations of 0.52 and 0.31 (P <0.001) were found between NI per 4.5 t DM and PW and BW, respectively. The NI per 4.5 t DM was higher in cows between 3- to 9-years-old than first lactation cows. The NI per 4.5 t DM was also strongly correlated with the milk, fat and protein yields (P <0.001). This study confirms that PW, rather than BW, better reflects the genetic capability of a cow to convert feed into farm profit.

Effect of dam size and nutrition during pregnancy on fetal testicular development in sheep - Asmad K; Kenyon PR; Parkinson TJ; Pain SJ; Lopez-Villalobos N; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2013)
In male sheep, testicular development is almost complete at birth. Testicular cells start to differentiate as early as Day (D) 27 of gestation followed by steroidogenesis and the activation of associated enzyme systems (Rhind 2004). Sertoli cells are present at around D34 and replication continues postnatally (Hochereau-de Reviers et  al. 1987). Seminiferous cords that will develop into tubules appear between D35 and D40 (Sweeney et al. 1997; Rhind et al. 2001). By D70 the rete testis is organised in the centre of testis (Sweeney et al. 1997) and between D35 and D85 the GnRH neuronal system develops in the hypothalamus (Caldani et al. 1995). Testicular gonocytes are typically observed between birth and 25 days after birth, and then progressively differentiate into spermatogonia up to 70 days after birth (Sharpe et al. 2003).

Effect of different herbage mixes on lamb meat quality - Schreurs NM; Kenyon PR; Morris ST; Blair HT; Somasiri SC; Kemp PD (Proceedings of the New Zealand Society of Animal Production, 2013)
In New Zealand there is increasing use of alternative forage species for finishing lambs. The alternative forages have a higher feeding value as a consequence of the dry matter yield and chemical composition providing for greater intakes and a higher nutritive value (Kemp et al. 2010). Each forage species is unique in its nutrient composition and may provide an advantage for animal production at different times of the year (de Ruiter et al. 2007). To take advantage of the unique attributes of individual forage species, herbage mixes have been proposed to further boost lamb growth.

The effect of ewe prelamb body condition on triplet lamb performance in a commercial flock - Everett-Hincks JM; Stevens DR; Rendel JM; Smith TR; Smith PJ (Proceedings of the New Zealand Society of Animal Production, 2013)
Triplet-bearing ewes (n = 999) were identified at pregnancy scanning (PS) and randomly assigned to two pasture feeding treatments through to lamb weaning, FeedPlus (FP) and Control (C). FeedPlus ewes were fed according to theoretical requirements based on live weight and a fetal number of three while C ewes were fed as for twinning ewes. Ewe body condition score (BCS) was similar for FP and C ewes at PS (BCS 3). FP ewes had higher BCS than C ewes at set-stocking one month before the mean lambing date (PL, BCS 2.9 ± 0.1 versus 2.6 ± 0.1, P <0.001). Every unit increase in BCS at PS improved litter survival to weaning by 0.33 ± 0.17 of a lamb. An increase of BCS at set-stocking improved litter survival to weaning by 0.45 ± 0.18 of a lamb (P <0.05). Litter weight increased with increasing BCS PL (β= 1.2 ± 0.5 kg/unit BCS, P <0.05). Low BCS ewes (BCS ≤2.5) at PS weaned 3.5 kg less lamb than medium BCS ewes at PS (BCS ≥3) (82.4 ± 1.1 kg versus 85.9 ± 1.4 kg, P <0.05) when rearing triplets. Pre-lamb BCS had a positive effect on lamb weaning weight (β= 1.3 ± 0.6 kg/unit BCS, P <0.05) and on lamb growth rates from birth to weaning (β= 13.5 ± 6.0 g/day per unit increase in PL BCS, P <0.05). The study highlighted the importance of ewe body condition score at PS and PL on triplet ewe performance.

Effect of heifer live weight on calving pattern and milk production - McNaughton LR; Lopdell T (Proceedings of the New Zealand Society of Animal Production, 2013)
Many heifers on New Zealand dairy farms fail to reach their target live weight. This failure leads to lost milk production and poorer reproductive performance. This study investigated effects of breed and region on heifer live weight and also effects of pre-calving heifer live weight (18–21 months) on milk production. Less Friesian heifers reached their target live weight than Jerseys, or Crossbreds (85.3 versus 89.3 versus 88.1%; P <0.001). Heifers born in Otago (91.9%) and Taranaki (91.8%) were the closest to achieving their target live weight, whilst those born on the West Coast (85.6%) and Northland (86.0%) had the greatest number of heifers not reaching their target. Heifers that had only one calving recorded on the database were a significantly lower percentage of target live weight than those heifers that had two calvings recorded (83.5% versus 87.1%; P <0.001). In heifers with a live weight record between 18 and 21 months of age, every 1% increase in the percentage of target live weight attainedwas associated with an increase in milk volume of 23 ± 0.6 litres in the first lactation and 24 ± 0.9 litres inthe second lactation. Further work is required on the economics of feeding heifers to achieve their target live weight.

The effect of milking frequency in early lactation on gene expression in the bovine mammary gland - MacLean PH; Stelwagen K; Maqbool N; Oden K; Murney R; Couldrey C; Singh K (Proceedings of the New Zealand Society of Animal Production, 2013)
In ruminants, altered milking frequency influences milk production due to either an increase in the number of secretory mammary epithelial cells and/or the activity of these cells (Stelwagen 2001). Microarray studies examining the response of mammary epithelial cells to either increased (Connor et al. 2008) or decreased (Littlejohn et al. 2010) milking frequency, reportedaltered gene expression in several regulatory pathways. These changes would appear to be locally regulated within the mammary gland, as milk production is different in different glands within the same udder depending on the milking frequency of individual glands (Stelwagen 2001). Therefore, the udder lends itself well as a model system to study the effect of different milking frequencies by comparing the response in adjacent udder halves (Murney et al. 2012).

Effect of post grazing residual and concentrate feeding on milk production in early lactation - Bryant RH; Harkin C; Vazathara T; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2013)
Two strategies to increase nutrient supply to early lactation dairy cows were compared and the cumulative effects on pasture quality and milk production were investigated. In a farmlet experiment the effect of feeding pasture only, or pasture plus concentrate (4kg/cow/day) at low (3.5 cm) or high (5.0 cm) post-grazing pasture residual (PGPR) was determined using a 2 x 2 factorial combination. Milk production for four groups of eight Friesian x Jersey dairy cows was measured within three consecutive grazing rotations during the first 12 weeks of lactation. PGPR for the low and high treatments remained constant throughout the 12 week period at 3.7 and 4.5 cm respectively. Mean milk solids production in the first, second and third rotation were 1.99 ± 0.12, 2.14 ± 0.10 and 2.01 ± 0.09 kg MS/cow/day respectively. Increasing PGPR from 3.7 to 4.5 cm did not affect pasture quality, milk production or milk composition. Concentrate feeding increased milk solids yield by 0.30 kg (P < 0.05) in the third rotation. Concentrate feeding also increased milk protein yield by 68 g (P <0.05), 104 g (P <0.05) and 167 g (P <0.001) in the first, second and third rotation respectively. When pasture quality is not altered by PGPR, feeding a concentrate is more effective at increasing nutrient supply than raising grazing height.

The effect of re-milking following extended non-milking periods on the proliferation and apoptosis of mammary gland epithelial cells in dairy cows - Mallah GS; Dobson J; Moon S; Henderson HV; Molenaar A; Guan J; Singh K (Proceedings of the New Zealand Society of Animal Production, 2013)
In dairy cows, the increase in milk yield from parturition to peak lactation is attributed to an increase in the secretory activity of mammary epithelial cells (MECs) (Capuco et al. 2001). However, following peak lactation, there is a decline in milk production, which is attributed to the loss of MECs by programmed cell death or apoptosis (Capuco et al. 2001). The role of involution and the factors that regulate it in the bovine mammary gland are not well understood. Previous studies have characterised the process of involution in the bovine mammary gland by determining whether involution is reversible following an extended milk stasis. Involution was fully reversible following seven days of non-milking (Dalley & Davis 2006), but was only partially reversible following longer non-milking intervals (Noble & Hurley 1999; Singh et al. 2012).

Efficiency of beef breeding cows that vary in live weight and milking potential - Law NL; Hickson RE; Lopez-Villalobos N; Kenyon PR; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2013)
Size and milking potential of beef breeding cows affect their productivity and efficiency. This experiment compared the productivity and efficiency of straightbred Angus (AA) (high live weight, low-milk potential), Angus-cross-Holstein Friesian (AF) (high live weight, high-milk potential), Angus-crossKiwicross (AK) (moderate live weight, high-milk potential) and Angus-cross-Jersey (AJ) cows (low live weight, high-milk potential). High-milk lines produced heavier calves at weaning than the low-milkproducing AA. AF and AK cows weaned the heaviest calves at 225 ± 3 kg and 224 ± 4 kg respectively. These calves were heavier than those weaned by AJcows (212 ± 3 kg). All of these three genotypes weaned heavier calves than AA cows (197 ± 3 kg). In turn, all three high-milk lines had greater weaning efficiency ((weaning weight of calf/weight of cow at calf weaning) x100) than AA cows which had an efficiency of 36.7 ± 0.7%. AJ and AK cows were the most efficient at 46.7 ± 0.7% and 46.0 ± 1.0%, respectively. AJ cows were also more efficient than the AF cows (44.0 ± 0.8%). Increased milking potential and decreased live weight of breeding cows increased their efficiency of production.

Estimating 24-hour milk,fat and protein yields and somatic cell count for automatically milked cows in pastoral production systems - Jago JG; Burke JK (Proceedings of the New Zealand Society of Animal Production, 2013)
Currently, there are no accepted methods for conducting herd tests on farms using fully automated milking systems in New Zealand. This study used data from the DairyNZ Greenfield pasture-based automatic milking research farm to evaluate six milksampling protocols to estimate daily milk, fat and protein yield and somatic cell count (SCC). Total milk, fat and protein yield, and SCC were estimated using all samples collected within 12, 16, 18, 24 and 36 hours from the start of the herd test and for a single test-day sample and compared with values calculated from a 48-hour gold standard herd test day. The correlation coefficient for milk and protein yields were relatively consistent when the sampling interval was shortened to 12 hours (r = 0.95, r = 0.94 for 12 hour milk yield and 12 hour protein yield). However, for fat yield it reduced from 0.96 for a 36 hour sampling interval to 0.88 for a 12 hour interval. The number of cows without a milking increased from 6.7% to 27.8% when the sampling interval decreased from 36 to 12 hour. A 24 hour sampling interval provided high correlations for milk, fat and protein yields, and SCC, with a 48 hour gold standard and minimised the number of missed cows.

Estimation of protein utilization efficiency and metabolisable protein efficiency in lactating cows grouped by breeding worth - Wheadon NW; Cheng L; Dewhurst RJ; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2013)
The efficiency of conversion of feed protein to milk protein (protein use efficiency (PUE)) is important in ruminants as protein is the most valuable component of milk (Ryan et al. 2011). It is also essential to reduce nutrient and resource costs when the efficiency of nutrient use is low (Roberts, 2008). In ruminants, dietary protein has three main routes of metabolism, namely microbial fermentation in the rumen, absorption in the small intestine, and catabolism and excretion of excess digestible protein into faeces and urine nitrogen (Agricultural Research Council 1980). This makes PUE difficult to explain and predict because of the interaction of these pathways. Rumen degradable protein (RDP) and metabolisable protein (MP) are the two main protein pools for milk protein production.

Evaluation of lambs subjected to a targeted selective treatment anthelmintic regime - Greer AW; Pettigrew CA; Logan CM (Proceedings of the New Zealand Society of Animal Production, 2013)
Targeted selective anthelmintic treatments (TSTs) can identify individuals less reliant on anthelmintic, information from which could be utilised to select lambs based on anthelmintic requirement. However, it is important to first determine if selection based on anthelmintic requirement compromises genetic potential for productive traits. Sheep Improvement Limited (SIL) estimated breeding values (eBVs) for production traits and associated indexes for 214 female lambs and 158 male Coopworth lambs were compared with their requirement for anthelmintic following exposure to a liveweight gain-based TST regime. Mean liveweight gain for both sexes was reduced with increasing anthelmintic requirement (P <0.001). Favourable increases in eBVs with decreasing anthelmintic requirement wereobserved for fecundity in both sexes (P = 0.003) and for survival in females only (P = 0.03). No effect was observed for eBVs for maternal survival, weaning weight, maternal weaning weight, live weight at eight months of age, and live weight and fleece weight at 12-months of age (P >0.05 for all). Dual purpose index values for resilience increased with decreasing anthelmintic requirement (P <0.001) while meat yield index and overall productivity were not affected (P >0.05 for both). It is concluded that selection of lambs for low anthelmintic requirement can be made with no apparent compromise in the genetic potential for production traits.

Ewe body condition score and the effect on lamb growth rate - Mathias-Davis HC; Shackell GH; Greer GJ; Bryant AL; Everett-Hincks JM (Proceedings of the New Zealand Society of Animal Production, 2013)
Data were analysed to investigate the association between ewe body condition score (BCS) and lamb growth rate (LGR). Ewe BCS was assessed on a scale of 1 to 5 pre-lambing (BCSL) and at weaning (BCSW). Change in BCS throughout lamb rearing (BCSChange) was calculated as the difference between BCS at weaning and pre-lamb. The three way interaction between birth rank, BCSL and BCSChange was significant (P <0.05). When the interaction was examined for birth rank, it was significant between BCSL and BCSChange in singles (P <0.05) and twins (P <0.01), but not in triplets. In singles and twins, lambs with the highest LGR were from dams that had high BSCL and negative BCSChange or those with low BCSL and positive BCSChange. Triplets had a similar trend whereby lambs with the highest LGR were from dams with a high BCSL and a negative BCSChange. This study suggests that if farmers manage their ewes to achieve a high BCS at lambing time this is likely to improve lamb growth to weaning. In addition, identifying ewes with a low BCS at lambing and preferentially feeding them to increase BCS during rearing may increase single and twinlamb growth rates.

Ewe live weight and body condition in mid-to- late-pregnancy does not affect the maximum heat production capacity of its lamb at birth - Martin NP; Kenyon PR; Hickson RE; Kerslake JI; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2013)
Under pastoral conditions, lambs are often exposed to wind, cold and rain that result in neonatal mortality. Thus any improved thermoregulatory response has the potential to increase lamb survival. Especially in light lambs, there is a strong negative relationship between birth weight and mortality (Everett-Hincks & Dodds 2008). Birth weight also regulates the lamb’s thermoregulatory capability (Kerslake et al. 2010). Lamb birth weight is influenced by ewe live weight, ewe bodycondition score and the variation in these parameters (Everett-Hincks & Dodds 2008; Schreurs et al. 2012). Therefore, ewe live weight and ewe body condition score may influence the thermoregulatory capability of the newborn lamb and its survival to weaning.

Genetic parameters of stayablity measures in a dairy goat herd - Wheeler M; Foote BJ; Foote JF (Proceedings of the New Zealand Society of Animal Production, 2013)
Doe longevity is an important factor in dairy goat farm productivity and sustainability, as the economic and environmental cost of raising replacement breeding animals per unit of milk production has less impact when spread over a longer period of return. Although stayability has been studied in sheep and cattle, there is little information regarding genetic parameters for longevity traits in New Zealand dairy goats.

Genome wide DNA methylation patterns and transcription analysis in sheep muscle - Couldrey C; Brauning R; MacLean PH; Henderson HV; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2013)
The Carwell phenotype is a desirable inherited muscular hypertrophy of the Longissimus dorsimuscle in Poll Dorset sheep that does not have any detrimental effect on eating quality, fat deposition or detectable meat tenderness. The Carwell haplotype has been localized to a 350kb region on the distal end of OAR18 near the Callipyge locus (Nicoll et al. 1998) containing three known genes. However, in spite of considerable effort in sequencing and resequencing, the causative mutation has not been identified. Although unsuccessful in identifying the causative mutation, these studies have revealed that the Carwell phenotype displays an imprinted inheritance pattern, with increased muscling associated with inheritance from the sire but not the dam.

High hydrostatic pressure treatment increases cryo-tolerance of in vitro produced bovine embryos - Popovic L; Berg DK; Pribensky C; Henderson HV; Wells DN (Proceedings of the New Zealand Society of Animal Production, 2013)
Cryo-preservation is a critical tool to manage the logistics of implementing assisted reproductive technologies in practice, which depend upon the availability of synchronised recipient cows for embryo transfer. However, the various cryo-preservation methodologies are noted for compromising the integrity of cells within the embryo, hence reducing subsequent viability. The challenge faced by practitioners in this field isto increase the success rate of producing offspring following embryo cryopreservation.

In vitro ruminal fermentation and methane production from maize silage mixed with high or low quality ryegrass - Jonker A; Pacheco D (Proceedings of the New Zealand Society of Animal Production, 2013)
Methane is the main greenhouse-gas produced by New Zealand agriculture (Ministry for the Environment 2011). The methane loss from ruminants generally ranges from 4.5% to 9% of gross energy intake (Hammond et al. 2009). This indicates there is scope for lowering methane production. Replacing pasture forage with maize silage could decrease methane emission by altering fermentation patterns and by reducing rumen pH or ruminal retention time with the addition of starch to the diet (Beauchemin et al. 2008). However, Waugh et al. (2005) found that methane yield (g/kg DM intake) increased when pasture forage was substituted with up to 35% maize silage in dairy cows fed at similar intakes. Other literature suggests that methane yield in cattle responds in a quadratic manner when pasture forage is substituted with maize silage or grain (Blaxter & Wainman 1964; Arndt et al. 2010; Hassanat et al. 2012). This effect is associated with pasture forage quality (Kirkpatrick et al. 1997).

Insulin response to a glucose tolerance test in 18-month pregnant heifers as a predictor of subsequent survival - Hutchinson KJ; Davis SR; MacKenzie DDS; Blair HT; McNaughton LR; Sanders K; Spelman RJ (Proceedings of the New Zealand Society of Animal Production, 2013)
A decline in dairy cow fertility in the USA and in the UK (Beam & Butler 1999; Royal et al. 2000) has also been noted in New Zealand. Calving rate, the proportion of cows re-calving within the first 42 days of the subsequent seasonal calving period, in New Zealand decreased from approximately 70% in 1991 to 60% in 2004 (Harris et al. 2006). There has been no further deterioration in subsequent years.

A Longitudinal study of production and survivability of carry-over cows in a commercial dairy herd - Pangborn MC; Woodford KB (Proceedings of the New Zealand Society of Animal Production, 2013)
In earlier work, we showed that two cohorts of carry-over cows produced 10% more milksolids (MS) in the first lactation (2008/09) subsequent to the carry-over (non-lactating) season. Here we present further production data for this cohort through to the fourth post-carry-over lactation, together with production data for two further cohorts through to their second and third post-carry-over lactations respectively, and compare this to production from non-carry-over (annual calving) cows of similar breed and breeding worth (BW) in the same herd. Carry-over cow cohorts produced more MSthrough to and including the third post-carry-over lactation relative to non-carry-over cows. We term this additional production the ‘holiday effect’. First year MS holiday effects were 57 kg (13%) and 106 kg (23%); second year holiday effects were 36 kg (8%), 48 kg (10%) and 31 kg (6%); and third year effects were 48 kg (10%) and 41 kg (8%). Aggregate survivability through to the fourth post-carry-over lactations of 83%, 82% and 71% respectively were broadly consistent with national survivability statistics. It is concluded that the bio-economics of carry-over cows are worthy of consideration, particularly for young cows of high BW and PW status which have previously given birth at least once.

Mastitis pathogens isolated from dairy cattle that were managed on conventionally or organically maintained matched farmlets - Ullah Z; Margerison JK; Simcock DC; Thatcher A; Lopez-Villalobos N (Proceedings of the New Zealand Society of Animal Production, 2013)
Mastitis is a common disease of dairy cattle causing significant economic loss (Seegers et al. 2003), which has been estimated to cost the New Zealand dairy industry $180 million annually (Malcolm 2006). It has been shown that dairy cattle in the first lactation are particularly susceptible to infections from environmental pathogens, including Streptococcus uberis(Woolford & Lacy-Hulbert 1996) and that this was the most common environmental pathogen, involved in the development of clinical mastitis of dairy cattle in New Zealand (Pankey et al. 1982, 1996; McDougall,1999). Studies completed in the Waikato region of New Zealand described the pathogens isolated from dairy cattle with clinical mastitis and reported that 27 to 75% of cases were infected with Streptococcus uberis, whereas 9 to 10% were Coagulase-negative-staphylococci(CNS), 3 to 5% were Staphylococcus aureus, 2 to 5% were coliforms and finally 1.5 to 4 % were  Strep.

Milking reproduction - Clarke IJ (Proceedings of the New Zealand Society of Animal Production, 2013)
Reproductive function is influenced by metabolic status and is compromised in conditions of negative energy balance. In the recent past, significant advances have been madein our understanding of how the brain regulates appetite and energy expenditure, largely due to the identification of blood borne factors that act on the neurons in the hypothalamus that produce the so-called ‘appetite regulating peptides’. This review provides an overview of the control of energy balance and the interface between ‘appetite regulating’ systems and gonadotropin releasing hormone secretion and action. This is placed in the context of the lactating dairy cow in an effort to understand what might cause poor reproductive performance. It is apparent that we know significantly more about the relationship between energy balance and reproduction in non-bovine species. This review indicates areas which deserve further attention in the dairy cow.

Milksolids production of dairy cows grazing lucerne and perennial ryegrass in spring - Smith G; Bryant RH; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2013)
The potential of New Zealand grazing systems is dependant on the dry matter (DM) yield, nutritive characteristics, and utilisation of pasture. The most common pasture is a mixture of ryegrass and white clover, which is tolerant of a wide range of environments and management (Kemp et al. 1999). However species such as these with shallow root systems and poor growth in high temperatures will have reduced herbage accumulation and quality during dry summer periods (Hoglund & White 1985). As demand for irrigation has increased to alleviate these problems, it has also raised questions about water allocation impacts on dairy farm production and profit (Thorrold et al. 2004). For Canterbury, which experiences hot, dry summers, lucerne is a potential source of high quality feed due to its active warm season growth and greater water use efficiency (Mills & Moot 2010).

Modelling the effect of temporary once-a-day milking durinmg early lactation on dairy farm production and profitability - Khaembah EN; Rius AG; Beukes PC; Levy G; Gregorini P; Roche JR; Kay JK; Phyn CVC (Proceedings of the New Zealand Society of Animal Production, 2013)
The DairyNZ Whole Farm Model was used to predict the effect of temporary once-a-day (OAD) milking during the calving period on milksolids (MS) production, farm profitability and herd body condition score (BCS) at dry-off. Farms from three regions and three independent seasons were modelled for: wholeseason twice-a-day (TAD) milking of all cows (Control), OAD milking of all cows for eight days immediately post-calving and TAD milking thereafter (Col OAD), OAD milking of the herd for three weeks from the planned start of calving (PSC) and TAD milking thereafter (3 wk OAD), and OAD milking of the herd for six weeks from the PSC and TAD thereafter (6 wk OAD). Model outputs indicated MS production (kg/ha) losses of 2, 1.2 and 3.7% and profit ($/ha) losses of 6.5, 4.5 and 11.6% for the Col OAD, 3 wk OAD and 6 wk OAD regimes, respectively. Slight improvements in dry-off BCS were predicted for the OAD milking regimes, comparedwith the control. Milking the herd OAD for three weeks from the PSC may be the prefered strategy to offer labour, lifestyle and animal health benefits with the smallest losses of MS production and farm profit.

MRI technology to better understand placental placental function in sheep - A pilot study - van der Linden DS; Oliver MR; McCoard SA (Proceedings of the New Zealand Society of Animal Production, 2013)
The placenta is the organ responsible for exchange of nutrients and waste products between the mother and her fetus (Bell & Ehrhardt 2002). It is therefore the main regulator of fetal growth (Murphy et al. 2006). In sheep, placental exchange of nutrients occurs at sites called placentomes (Ford 2000). Placentomes are comprised of cotyledons on the chorioallantoic membrane which attach to discrete caruncles on the uterine wall (Ford 2000). Ovine placentomes can be classified into four types (A, B, C and D) based on their gross morphological appearance (Vatnick et al. 1991). The distribution of placentome type, and size of individual placentomes can be influenced by many factors.These include nutritional status of the dam, placental blood flow, oxygen availability and altitude (Gardner et al. 2002; Osgerby et al. 2002, 2004; Penninga & Longo 1998).

mTOR signalling in lactating bovine mammary gland - McCoard SA; Wards N; Singh K (Proceedings of the New Zealand Society of Animal Production, 2013)
The mammalian target of rapamycin (mTOR) is a protein kinase that has a well established role in the regulation of a range of cellular functions in response to hormones, growth factors and amino acids (Wang & Proud 2011). The role of mTOR signalling in the regulation of milk protein synthesis in the mammary gland of ruminants is not well understood. Understanding this mechanism is an important step towards developing intervention strategies on farm, such as the supply of nutrients, to modulate milk protein output.

The New Zealand beef cattle industry - Morris ST (Proceedings of the New Zealand Society of Animal Production, 2013)
A quick cursory glance of the past 71 Presidential Addresses reveals they usually take one of three forms. Some have given an overview of the agricultural or animal science research scene with particular reference to funding and in particular the shortfall of funds, others have reviewed the Society’s activities usually through analysis of membership and papers presented at Annual Conferences and suggested future directions for the Society, while others have made a personal statement about an industry or research area. I have chosen the latter and want to speak today about beef production in New Zealand. Beef production gets little recognition in the mainstream press or by many of our farmer politicians. In fact I would suggest many of our Society members would know little about beef production on our farms.

Quantitative trait loci associated with variation in maximum milk flow rate in Friesian -Jersey cross bred cows - Davis SR; Littlejohn M; Ellison R; Spelman RJ (Proceedings of the New Zealand Society of Animal Production, 2013)
On New Zealand dairy farms, the milking process consumes more than half of the available labour hours (Jago et al. 2010). While some recent research has shown some potential to improve labour efficiency of dairy farms during milking (Jago et al. 2010), the speed of milking is, in large part, dictated by the slowest milking cows in the herd.

Rapid analysis of moxidectin in plasma - Hughes DC; Fraser K; Miller CM; Leathwick DM (Proceedings of the New Zealand Society of Animal Production, 2013)
Intestinal parasites are a significant impediment to the productivity of grazing livestock in New Zealand (Scott et al. 2008). They are regarded by New Zealand sheep farmers as their most important animal health issue (Lawrence et al. 2007). The New Zealand deer industry estimated that parasites cost as much as 5% of the total farm revenue (Mackintosh & Wilson 2003). On most farms controlling parasites in order to minimise their impact on animal performance relies heavily on the use of anthelmintics (Lawrence et al. 2007), but their continued usefulness is threatened by the development of worm populations resistant to these drugs (Waghorn et al. 2006a, 2006b). Studies aimed at developing more sustainable worm management practices will be important for maintaining the future productivity and profitability of many farming operations.

Relative performance of three strains of fine-woolled Merino sheep farmed on Waikato hill country - Sumner RMW; Henderson HV (Proceedings of the New Zealand Society of Animal Production, 2013)
Flocks of Saxon (ex Tokanui Research Station), Merryville (ex Tara Hills Research Station) and Fine Peppin (ex Tokanui Research Station) Merino sheep were established at the Whatawhata Research Centre to investigate their relative productivity under North Island hill country conditions. Production data were collected for five years. The Fine Peppin ewes had a higher reproductive rate (0.1 ± 0.05 (standard error of difference) lambs weaned/ewe joined) with a higher lamb birth weight (0.37 ± 0.08 kg), lamb weaning weight (1.9 ± 0.4 kg) and yearling weight (3.5 ± 0.6 kg), a higher ewe greasy fleece weight (1.2 ± 0.1 kg) that was longer (7 ± 2 mm) and coarser (3.0 ± 0.2 μm) with a greater coefficient of variation of fibre diameter (2.2 ± 0.4 %), lower brightness (-1.3 ± 0.4 CIE Y units) and more yellow (1.1 ± 0.2 CIE (Y-Z) units) than the Saxon. The Merryville was intermediate between the other two strains for most characteristics. The yearling fleece of each strain exhibited similar trends to the adult fleece. On the basis of the measured performance, and applying wool and lamb price trends between 2007/08 and 2011/12, the differential returns per ewe of the Fine Peppin would be expected to exceed that of the Saxon by $8.80 with the Merryville being intermediate.

Review of milk payment systems to identify the component value of lactose - Sneddon NW; Lopez-Villalobos N; Hickson RE; Shalloo L (Proceedings of the New Zealand Society of Animal Production, 2013)
New Zealand’s export dairy product mix has shifted towards the production of whole milk powder. This has resulted in a deficit in milk lactose to meet international standardisation requirements for whole milk powder. Currently, the deficit in lactose is filled using imported lactose with an estimated cost of New Zealand dollars 300 million annually. This study compares payment systems from America, Europe, Australia and New Zealand, and outlines possible strategies for payment for lactose to New Zealand dairy farmers. The prominent milk payment system in New Zealand is the ‘A+B-C’ multiple component pricing system, where A and B are the monetary values per kilogram of fat and protein and C is the penalty per litre of milk volume. An alternative payment system that may encourage farmers to increase the supply of lactose could be ‘F+P+L-V’ where F, P and L are the monetary values of fat, protein and lactose respectively and V is the penalty per litre of milk volume. This payment system is currently in operation at one small New Zealand dairy processor. This study has shown that the ‘F+P+L-V’ payment system results in smaller deviation from the true value of the milk for differing breeds, milk compositions and product mixes than the current ‘A+B-C’ system of milk payment.

Some lessons from using zinc-salt treatments to protect dairy cows against facial eczema - Morris CA; Hickey SM (Proceedings of the New Zealand Society of Animal Production, 2013)
A trial at AgResearch Ruakura, evaluating two different methods of administering zinc++(Zn) salts to protect cows from facial eczema, was carried out in lactating dairy cows to study the variation in concentrations of blood Zn++. The treatments were: continuous supply of zinc sulphate (ZnSO4) through water troughs (n = 10 cows), versus daily oral drenching with zinc oxide (ZnO) (n = 10 cows). Responses in daily milk yields, and concentrations of Zn++in blood were recorded twice weekly over four weeks for each cow. The ZnSO4trough treatment took ten days for blood Zn++concentrations to equilibrate, after which the sampling-day average ranged from 20–26 μmol/L. Between-cow repeatability was 0.42 ± 0.15. The daily ZnO treated cows equilibrated after drenching for three days. Average blood Zn++concentrations then ranged from 24–29 μmol/L. Between-cow repeatability was 0.44 ± 0.17. Dailymilk yields did not differ significantly between treatments. Target ranges for blood Zn++concentrations to provide protection against facial eczema in lactating dairy cows of 18–34 μmol/L were published 26 years ago. These may need to be re-assessed, with changes in breed composition and increases in milk yield over that time within the national herd.

Spatial-time correlation between milk urea with milk components and somatic cell score of bulk milk samples from farms supplying milk for cheese and milk powder manufacturing - Garcia-Muniz JG; Lopez-Villalobos N; Burken JL; Sandbrok T; Vazquez-Pelaez CG (Proceedings of the New Zealand Society of Animal Production, 2013)
Milk urea nitrogen (MUN) has been used to indicate the dietary protein/energy balance for the dairy cow, and may be negatively associated with the content of valuable milk components for the manufacture of dairy products. The objective of the study was to model the temporal pattern of the correlation between MUN and the percentages of fat (FP), protein (PP), lactose (LP) and total milk solids (MSP), and somatic cell score (SCS) (log2somatic cell count) of bulk milk samples from farms supplying milk for the manufacture of cheese and milk powder. Daily records of milk delivery dates, the composition of bulk milk samples for FP, PP, LP, MSP, SCS and MUN from 28 seasonal supply dairy farms were analysed. The results show there is a negative association between MUN and milk components. The concentration of MUN in milk of New Zealand cows is high compared with that of milk from cows fed a total-mixed-ration, due to the high crude protein content in the pasture fed to dairy cows in New Zealand.

Uterine expression of oestrogen receptor alpha in Suffolk and Cheviot ewes at Day 19 of pregnancy, following embryo transfer - Sequeira M; Pain SJ; Sartore I; Meikle A; Kenyon PR; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2013)
Whilst it is recognised that maternal uterine capacity has a marked influence on offspring birth weight and size (Walton & Hammond 1938; Allen et al. 2002; Jenkinson et al. 2007, 2012; Sharma et al. 2012), Sharma et al. (2010) demonstrated in reciprocal embryo transfer experiments that the maternal uterine environment exerts an effect on embryonic growth by Day 19 in early gestation, when maternal uterine capacity is not a limiting factor.

Verification of an automated camera-based system of oestrus detection in dairy cows - Hempstalk K; Burke CR; Kamphuis C (Proceedings of the New Zealand Society of Animal Production, 2013)
Accurate oestrus detection is critical in New Zealand dairy farming, where many farms operate a seasonal farming model and, therefore, rely on a compact calving spread and a short mating period to farm efficiently. Automated oestrus detection systems are available that automatically identify and draft cows in oestrus. There are two types of automatic systems available commercially in New Zealand; activity-based systems that involve pedometers/accelerometers and systems that detect mounting behaviour using a sensor attached to the animal’s back.

Are dairy heifers achieving liveweight targets? - McNaughton LR; Lopdell TJ (Proceedings of the New Zealand Society of Animal Production, 2012)
The reproductive performance of the national dairy herd has declined (Harris et al. 2006). Heifer rearing is one of eight "ingredients" for achieving good reproductive performance identified by the InCalf project (Burke et al. 2007). Many New Zealand dairy farmers graze their heifers on a run-off or pay a grazier to grow the heifers, with heifers commonly leaving the dairy farm at weaning, or nine months of age and returning at around 22 months of age.

Are faecal egg counts approaching their "sell-by" date? - Greer AW; Sykes AR (Proceedings of the New Zealand Society of Animal Production, 2012)
Historically, the primary determinant for the state of parasitism has been the concentration of nematode eggs in the faeces (FEC). This descriptor has a number of limitations that have implications for the development of drug resistance and hamper the identification of resilient livestock. A major fallacy is that FEC can reliably assess the worm burden, the need for anthelmintic and the efficacy of that treatment. FEC is a ratio, eggs per gram of faeces, not a quantity. Not only is the denominator ignored but interpretation of the numerator requires knowledge of nematode species present and female fecundity which can be affected by infra-population dynamics. By definition, a parasite exists at the expense of its host. As such, the consistent ability of resilient animals to maintain performance, despite a high FEC, strongly suggests that FEC does not provide a reliable indicator of the cost of parasitism. This manuscript reviews the factors that affect FEC and argues for a step change in our approach to the control of nematode parasitism in pastoral systems to one focused on individual treatments based on animal performance utilising radio-frequency electronic identification and automated weighing and drafting systems.

Associations of uterine pathology with milk production and effects of treatment with a nonsteroidal anti-inflammatory drug in dairy cows - Priest NV; McLeod KLM; McDougall S; Burke CR; Roche JR; Mitchell M; Greenwood SL (Proceedings of the New Zealand Society of Animal Production, 2012)
Subclinical endometritis (SCE) is a form of uterine pathology characterised by an increased proportion of polymorphonuclear cells (PMN) in the uterus post-calving. Previous studies demonstrated a negative association between SCE and lower milk production, with indications that systemic inflammation underlies this link. Accordingly, the hypothesis tested was that treatment with a non-steroidal antiinflammatory drug (NSAID) would increase milk yield in cows with ≥ 14% PMN at Day 14. In this study, ≥ 14% PMN in the cytological sample collected at Day 14 postpartum was defined as SCE. To test this hypothesis, 213 dairy cows were paired by calving date and Day 14 PMN%, then randomly assigned to three doses of a NSAID (Carprofen 1.4 mg/kg, n = 103) between 21 and 31 days postpartum or left as untreated controls (n = 108). The effect of the NSAID treatment on milk production was analysed using mixed models. While the results supported previous evidence of a negative association between SCE and milk production, NSAID had no effect on either PMN % at Day 42 or milk production (P > 0.1) in this study. The lack of a NSAID effect was possibly because SCE spontaneously resolved in more than 90% of the cases

Chinook salmon (Oncorhynchus tshawytscha) feed conversion efficiency: evaluation and potential for selection - Walker SP; Ingram M; J Bailey; Dodds KG; Fisher PJ; Amer PR; Symonds JE (Proceedings of the New Zealand Society of Animal Production, 2012)
Improving performance through selective breeding is a key priority for the New Zealand Chinook salmon (Oncorhynchus tshawytscha) aquaculture industry. The family selective breeding programme operated by The New Zealand King Salmon Company has successfully improved growth and quality after six generations of selection. However, feed conversion efficiency is not currently a direct breeding goal. Research was established to analyse daily feed intake and feed conversion ratio, a measure of feed efficiency, in 160 families over two spawning year classes. Daily feed intake assessment methodology employing digital X-radiography was validated and used to obtain repeated measurements of daily feed intake. Measurements of growth, and feed conversion ratio up to harvest size were also obtained. Genetic parameter estimates for daily feed intake and feed conversion ratio indicated that there are family differences for these traits. As a result the continued measurement of feed conversion ratio in The New Zealand King Salmon families and incorporation of the traits into The New Zealand King Salmon breeding programme is being considered.

A comparative analysis of genetic trends within the New Zealand sheep industry - Sise JA; Byrne TJ; Jopson NB; Young MJ; Amer PR (Proceedings of the New Zealand Society of Animal Production, 2012)
Rates of genetic progress made by Dual Purpose and Terminal Sire flocks in the New Zealand sheep industry between 1990 and 2007 have previously been examined (Amer 2009) and showed substantial gains in the rate of progress since the introduction of Sheep Improvement Ltd. (SIL) and SIL-ACE (Advanced Central Evaluation). Key findings from this earlier study showed that the rates of genetic progress doubled following the introduction of SIL, and increased by a further 50% after the introduction of the Beef + Lamb New Zealand Central Progeny test (CPT), which effectively evaluates the performance of key industry sires, providing the ... continued

A comparison of milk fat composition between pasture based cows supplemented with either canola meal or wheat - Williams DJ; Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2012)
Increasing the polyunsaturated fatty acid (PUFA) content of milk has been the focus of much recent research. Milk from pasture based cows has been reported to have a high content of PUFA, which can be further manipulated with the addition of supplements differing in fatty acid composition. This experiment used 980 Holstein-Friesian and Jersey crossbred cows in a split treatment design to determine the effect of canola pulp or wheat supplementation on milk fatty acid composition and milk solid production in a typical large pasture based herd. Principle component analysis was used to determine the most influential factors of change in milk composition. Milk solid production did not differ significantly between treatments (P > 0.05), C10:0, C12:0, C14:0, and C16:0 were very significantly (P < 0.001) decreased by the canola pulp treatment. C18:0 anteiso and conjugated linoleic acid were not significantly affected by treatment. C18:1 c9 and C18:1 t9 were very significantly increased (P < 0.001). C18:1 t11 was significantly increased in the canola pulp treatment (P < 0.03). These results show that canola pulp is a potentially valuable supplement for use in grazing based systems. The equivalent response to supplementation compared to wheat would recommend its use if cost on an ME basis was competitive.

Developing broodstock resources for farmed marine fish - Symonds JE; Walker SP; Van de Ven I; Marchant A; Irvine G; Pether S; Gublin Y (Proceedings of the New Zealand Society of Animal Production, 2012)
he expansion of New Zealand aquaculture will benefit from diversification into new high value finfish such as Yellowtail kingfish (Seriola lalandi) and Hapuku (groper, Polyprion oxygeneios). To ensure success, domesticated selected broodstock need to be established along with systems that can reliably produce high quality gametes and juveniles. Collections of wild Kingfish and Hapuku broodstock were completed by the National Institute of Water and Atmospheric Research from 2000 onwards. Over 100 wild broodstock have since been reared to establish the parental stocks. Wild females of both species are very fecund and millions of eggs have been produced each breeding season. One of the main challenges is to ensure that multiple parents contribute during spawning to create genetically variable, selected offspring (F1). Due to the current reliance on communal group spawning, multiplex microsatellite DNA marker panels were developed to determine the parentage of the resulting F1 progeny. Although F1 from multiple parents have been identified, some broodstock produced a disproportionate number of the progeny. This has highlighted the need to manage parental contribution to the F1, which would otherwise exclude many individuals from contributing to the gene pool. As a result we are developing techniques to control mating and to maximise the number of founding wild parents in the programme.

Development of a visual scoring system for ovine pneumonia at the processing plant - Baird HJ; Clarke SM; PL Johnson (Proceedings of the New Zealand Society of Animal Production, 2012)
Pneumonia in sheep is a consequence of multiple infectious agents compromising the host’s immune system, often with the aid of environmental factors. Chronic non-progressive pneumonia (CNP) and acute fibrinous pneumonia (AP) are the main concerns to the New Zealand sheep industry. AP occurs in sheep of all ages and is more common in older lambs during the late summer early autumn period. CNP is often seen in lambs aged between five and ten months of age. Clinical diagnosis is difficult with affected lambs showing few, if any, clinical signs of illness as reviewed by (Alley 2002). Accurate diagnosis requires examination of the lung. ... continued

Development of epigenomic analysis in agricultural animals - Couldrey C; Brauning R; Retzel EF; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2012)
Advances made in DNA sequencing technologies over the past 15 years (Zhao & Grant 2011) have resulted in genome wide selection for production traits becoming a reality. Soon all sequence variations in each individual in closed breeding schemes will be known. What is not currently known is how to rank these variations, especially those that involve changes in gene expression rather than amino acid sequence. In order to continue making genetic progress we will need an understanding of how epigenetics affects gene expression and ultimately phenotype.

DNA methylation events in the áS1-casein-encoding gene associated with involution and re-initiation of lactation in dairy cows - Pryor S; Swanson K; Couldrey C; Henderson H; Singh K (Proceedings of the New Zealand Society of Animal Production, 2012)
During lactation, prolactin activates STAT5 (Signal Transducer and Activator of Transcription5), which binds to conserved DNA sequence motifs in promoters of milk protein genes to stimulate their expression (Liu et al. 1997). Mammary gland involution induced by termination of milking is characterised by a rapid decrease in milk protein gene expression (Singh et al. 2008). Whereas milk production can be fully restored after seven days of ... continued

Does castration status have an effect on the quality of lamb meat? - Kerslake JI; Hely FS; Maclennan G; Lindsay S; Behrent MR; Campbell AW (Proceedings of the New Zealand Society of Animal Production, 2012)
Consumer demand for leaner lamb meat all-year-round and price incentives to produce heavier carcases means that in New Zealand ram lambs are often being left entire in an attempt to improve lamb growth rates (Fisher et al. 2010). While this offers potential improvements in on-farm returns, there are still perceived concerns in the market place that meat from entire ram lambs of a certain age may be unsatisfactory. Based on the latest scientific evidence (Young et al. 2006; Young et al. 2003) New Zealand processors make no distinction between carcasses from lambs of different genders. However, due to continual perceived concerns from consumers, ... continued

Dry matter intake and nitrogen losses of pregnant, non-lactating dairy cows fed kale with a range of supplements in winter - Miller ME; Bryant RH; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2012)
An outdoor winter-feeding study conducted over 14 days using 40 Friesian-Jersey cross dairy cows measured dry matter (DM) intake and nitrogen (N) excretion of cows fed kale with either barley straw (S), whole crop barley silage (WCBS) and Lotus pedunculatus silage (LS) fed with (LS+PEG) or without polyethylene glycol (LS-PEG). Treatment groups did not differ in DM utilisation of kale (80%) or apparent intake of kale (11.6 kg DM/cow/d). Total daily intake of N was lowest for S, intermediate for WCBS and highest for LS+PEG and LS-PEG (280, 323, 350 and 352 g N/cow/d, respectively). Urinary N excretion was lower (P < 0.05) on kale diets supplemented with either S or WCBS (202 and 186 g N/cow/d respectively) compared with LS+PEG and LS-PEG (227 and 239 g N/cow/d respectively). Supplement treatment did not affect total faecal N excretion but faecal N% was higher (P < 0.05) in LS treatment groups (3.05% in LS+PEG and 3.28% in LS-PEG), compared with WCBS (2.74%) and S (2.43%). This study indicates that the current commonly used feeding system of kale, supplemented with straw, is a feeding system that has a low urinary N excretion compared with alternatives.

Economic values for New Zealand dairy goats - Solis-ramirez J; Lopez-Villalobos N; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2012)
A deterministic bio-economic farm model was developed to estimate economic values (EVs) for important milk production traits affecting profitability and to define a breeding objective for New Zealand dairy goats. Costs, revenue, metabolisable energy requirements for maintenance and activity, pregnancy, lactation and growth of replacements were included in the farm model. Three payment systems were investigated; Current scenario: Total milk-solids; Scenario 1: Ratio 1:2 for fat (F) and protein (P) and Scenario 2: ratio 2:1 for F and P. A price of $13.00 per kg milk solids (MS) was assumed to calculate daily revenue per milk-solid component. A penalty of $0.04 per litre of milk was applied in the last two scenarios. Assumed values of 3.7%, 3.2%, 4.4% and 0.7% for fat, protein, lactose and minerals, respectively, were used to estimate price per kg of F and P in Scenarios 1 and 2. For the Current scenario, the EVs for fat, protein, lactose and volume were $11.64, $12.27, $12.39 and -$0.10, while the estimations in Scenario 1 were $14.49, $31.09, -$0.76 and -$0.14, respectively and in Scenario 2 were $28.92, $14.37, -$0.76 and -$0.14, respectively. The EV for live weight was -$2.16 across scenarios. The EVs estimated can be used to establish breeding objectives for New Zealand dairy goats.

The effect of milking frequency in early lactation on milk yield and milk protein gene expression in the bovine mammary gland - Murney R; Stelwagen K; Singh K (Proceedings of the New Zealand Society of Animal Production, 2012)
In dairy cows, increased milking frequency (MF) has a positive effect on daily milk yield (MY), providing dietary energy intake is sufficient to maintain the increase in production (Phillips et al. 1980). Short-term increases in MF during early lactation may have both an acute effect and a carry-over effect on MY once the animals have returned to less frequent milking (Hale et al. 2003). The critical period for increased MF to generate a carry-over effect on MY is within the first three weeks of lactation and may only need to be applied for as little as 14 days ... continued

The effect of re-milking following extended non-milking periods on lactation in dairy cows - Singh K; Swanson K; Henderson HV; Stelwagen K (Proceedings of the New Zealand Society of Animal Production, 2012)
In dairy cows, the cessation of milk removal for extended periods, such as drying-off, initiates the process of mammary gland involution. This results in a decline of mammary secretion and changes in secretion composition. Morphological changes in the mammary gland occur within the first week of non-milking, with extensive re-modelling by the third or fourth week. However, many alveolar structures are retained (Hurley 1989). Thus, involution may be reversible following extended non-milking periods (Noble & Hurley 1999). Milk yield is fully restored ... continued

Effect of resolving a sub-clinical uterine infection on plasma and follicular fluid steroid concentrations in early lactation dairy cows - Lopdell TJ; Berg MC; Green MP; Back PJ (Proceedings of the New Zealand Society of Animal Production, 2012)
Sub-clinical endometritis (scEndo) in early lactation affects ovarian follicle dynamics, delays a return to cyclicity, with changes in plasma and follicular fluid (FF) amino acid concentrations around the time of rebreeding. This study examined the effect of resolving scEndo in early lactation on plasma and FF oestrogen, progestagen, androgen and corticosteroid concentrations at the time of rebreeding in 46 dairy cattle. On D42 postpartum, cows were classified as having scEndo, clean or having resolved scEndo cased on uterine cytology on D21 of > 18% polymorphonuclear (PMN) cells amongst uterine nucleated cells. On D42 and D63 follicular and plasma samples were collected and steroid concentrations analysed. On D21 and D42, 35% and 7% of cows respectively were classified as having scEndo, with 81% of scEndo cows having self-resolved the infection by D42. In those cows that resolved scEndo, none of the plasma or FF steroid concentrations changed between D42 and D63, except for plasma progesterone (P = 0.08). Using a low (4%PMN) threshold to classify scEndo did not identify any significant changes in steroid concentrations. In contrast to previously described changes in plasma and FF amino acid concentrations, there were no significant effects on steroid concentrations when cows self-resolved a sub-clinical uterine infection.

Effect of the maternal environment on fetal growth at mid-gestation in sheep - Jenkinson CMC; Sharma RK; Kenyon PR; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2012)
Our group has previously shown that maternal size can affect embryonic development by Day 19 of gestation and lamb birth weight. This study set out to investigate the effect of the maternal uterine environment on fetal growth at mid-gestation. Pure-breed single embryos were transferred within and reciprocally between large (Suffolk: S) and small (Cheviot: C) breeds of ewes to establish four maternal environments; SinS, SinC, CinS and CinC. On Day 90 of gestation, 37 single-bearing recipient ewes (10 CinC, 7 SinC, 10 CinS and 10 SinS) were euthanased. Fetal body weight, fetal body dimensions and fetal organ weights, and placentome number and total weight were measured. Body weight was significantly (P < 0.001) smaller in Cheviot compared to Suffolk fetuses. However, Cheviot fetuses had heavier (P < 0.05) kidneys and liver than Suffolk fetuses. SinC fetuses had heavier (P < 0.05) pancreas than those from all other pregnancy groups. CinS fetuses tended to have longer (P < 0.10) fore- and hind-leg lengths than CinC fetuses. There were no differences (P > 0.05) in placental parameters between the pregnancy groups. The maternal uterine environment had no major effect on fetal weight, fetal dimensions and fetal organ mass at mid-gestation.

The effect of training to the milking parlour on the behavioural response to milking and milk production in first lactation heifers - Dowling SK; Sutherland MA (Proceedings of the New Zealand Society of Animal Production, 2012)
The objective of this study was to investigate the effect of training on the behaviour and milk production of heifers. Approximately three weeks prior to calving, heifers from two commercial farms were either trained over three days to the rotary milking parlour (TRAIN: n = 104) or left undisturbed in the paddock (CON: n = 113). Behavioural observations of heifers during the milking process were recorded over the first week of lactation. Behaviours recorded included the performance of flinching, stepping and/or kicking and the duration to attach the cluster. Individual heifer milk yields, milking durations, average milking flow rates and reattachment count of the cluster were recorded daily for the first six weeks of lactation. During the milking process, TRAIN heifers performed more leg lifts, a greater number of backward kicks and the number of times the milking cluster had to be reattached during each milking was greater than CON heifers. There was no difference in milk production measures between TRAIN and CON heifers. These results suggest that the method of training used in this study was not adequate to reduce the behavioural response of heifers to milking during the first week of lactation.

Effects of maternal nutrition during pregnancy on the growth and reproductive development of male sheep: a meta-analysis - Asmad K; Nakagawa S; Lopez-Villalobos N; Kenyon PR; Pain SJ; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2012)
Nutrient supply to the fetus is one of the crucial factors in the regulation of fetal growth and reproductive development. The effect of maternal nutrition can be exerted at all stages of fetal development, from conception until birth. A meta-analysis of maternal nutrition effects on the growth and reproductive development of male sheep offspring was undertaken using sixteen sheep studies. Eleven studies were included for prediction of the growth curves using a logistic growth model, and eleven studies were included for reproductive development and analysed using a mixed model. The meta-analysis suggested that, male sheep offspring undernourished during gestation had a significantly slower growth and lower testosterone levels while there were no statistically significant effects on testis weight, seminiferous tubule diameter or Sertoli cell count. The lack of a statistical effect on seminiferous tubule diameter and Sertoli cell count may be due to the limited number of studies examining the effects of maternal nutrition during pregnancy on male sheep offspring reproductive development. The meta-analysis reported here suggests that additional studies are warranted to more conclusively determine whether maternal nutrition during pregnancy effects male sheep growth and reproductive development.

Estimates of genetic parameters for flystrike in New Zealand Romney and Romney cross sheep - Pickering NK; Dodds KG; Blair HT; Hickson RE; PL Johnson; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2012)
Myiasis, or flystrike, is a major animal welfare problem for sheep that causes significant production losses and potentially death. It is estimated that the prevalence of flystrike is 3-5% in the national flock (Heath & Bishop 1995) and is estimated to cost the New Zealand industry $40 to $50 million annually (Beef + Lamb New Zealand 1999). These costs accrue via production losses through reduced wool and body growth, morbidity, and control strategy costs including insecticide, lamb shearing and crutching. ... continued

An evaluation of a progesterone-based diagnostic as an aid to re-insemination decisions in a seasonal, pasture-grazed dairy cow herd - Burke CR; Kamphuis C; Meier S; Pellow R (Proceedings of the New Zealand Society of Animal Production, 2012)
Progesterone-based diagnostic tests are commercially available to predict pregnancy status 19 to 23 days following an insemination, thus providing decision-making support for artificial breeding. The study objective was to evaluate the likely performance of such a test in a pasture-grazed, seasonal dairy farm. Progesterone was determined in milk samples collected twice weekly from 553 cows at the Lincoln University Dairy Farm. Receiver operating characteristic analysis was applied to these data to determine sensitivity, false positive rate and the positive predictive value using a range of progesterone threshold values for detecting non-pregnant cows. The gold standard was non-pregnancy as measured by ultrasonography. At an optimised threshold of 4.1 ng/mL, the sensitivity, false positive rate and positive prediction rate were 78%, 2.6% and 96% for detecting non-pregnant cows on Days 19 to 23. A major source of inaccuracy was the 28 cows with elevated levels of progesterone in milk on Days 19 to 23 after first insemination that were subsequently diagnosed non-pregnant. Another source of error was the inherent variance in progesterone concentration profiles among individuals. At a current cost of about $5 per test, this technology would have limited appeal for detecting non-pregnant cows in dairy systems where a satisfactory level of oestrus detection performance can be achieved.

Examination of New Zealand sport horse performance records and their suitability for the calculation of breeding values - Creagh FE; Lopez-Villalobos N; Hickson RE; CW Rogers (Proceedings of the New Zealand Society of Animal Production, 2012)
Currently there is no genetic evaluation of sport horses in New Zealand. The aim of this study was to develop a prototype model for genetic evaluation of New Zealand sport horses. Official performance data for the 2008/09 and 2009/10 seasons were obtained from Equestrian Sport New Zealand. Data on dressage points per start (Dpps), eventing points per start (Epps,) and show jumping total prize money (Stpm) were examined using descriptive statistics. There were between 902 and 1,472 horses registered in each discipline. All three data sets were skewed but approached normality after a log10 transformation. Overall between two and eight percent of sires in each discipline had five or more progeny records available for genetic analysis. A sire model with fixed effects of season, gender and age and a random effect of animal were used to calculate estimated breeding values (EBVs) for each discipline. EBVs for Dpps ranged from -0.066 to 0.158, for Epps from -0.076 to 0.182, and for Stpm from -0.523 to 0.993. The use of EBVs could lead to increased genetic gain and improved performance of New Zealand sport horses. However, the current data recording has several limitations.

Exploring the effects of growth rate and meat yield on lamb meat quality - Campbell AW; Maclennan G; Lindsay S; Behrent MR; Cheong I; Kerslake JI (Proceedings of the New Zealand Society of Animal Production, 2012)
New Zealand sheep breeding programs currently place high emphases on selection for growth and yield. High growth rates and high meat yield have both been reported as having negative effects on meat quality in pig, beef and poultry (Dransfield & Sosnicki 1999), probably due to changes in muscle structure and metabolism. In contrast, organic pork has shown to be less tender than conventional pork, which is thought to be due to organic pigs growing more slowly (Therkildsen et al. 2012). It is of importance to evaluate these relationships in lamb.

Expression of uterine progesterone receptor in Suffolk and Cheviot ewes at Day 19 of pregnancy, following embryo transfer - Sequeira M; Pain SJ; Sartore I; Meikle A; Kenyon PR; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2012)
Many animal studies have shown that uterine capacity has a marked influence on birth weight and size (Walton & Hammond 1938; Allen et al. 2002; Jenkinson et al. 2007; Sharma et al. 2012). However, in reciprocal embryo transfer experiments ...

Family-based selective breeding of New Zealand Abalone, Haliotis iris: challenges and opportunities - Symonds JE; Moss G; Jopson NB; Roberts R; Birss J; Heath P; Walker SP (Proceedings of the New Zealand Society of Animal Production, 2012)
In 2007 the National Institute of Water and Atmospheric Research in New Zealand initiated a family-based selective breeding programme for the New Zealand Abalone, Haliotis iris, with commercial partner OceaNZ Blue Ltd. to investigate the genetics of key performance traits in a cold water and a warm water site and the influence of the early rearing environment on family performance. A total of 101 Abalone families were established using farmed and wild broodstock from multiple locations around New Zealand. Families were reared separately for nine to 14 months prior to tagging at ~15-20 mm shell length and then combined. Families were also pooled during early rearing, up to seven days post-fertilisation and later genotyped. This allowed estimation of individual tank environment effects on family performance. Length, weight and growth rate have been recorded bi-annually plus evaluation of quality traits such as foot darkness and shell colour at a market size of ~80 mm. Relative family performance has generally been consistent across sites, but is moderately influenced by early environment. The growth traits were found to be highly heritable with high genetic correlations among traits indicating good response to selection for increased growth can be expected.

Genetic and phenotypic parameters for stayability in a New Zealand research flock - McIntyre SB; Newman SAN; Young EA; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2012)
Productive lifespan is important to commercial farmers, as ewes that are culled prematurely from the flock represent a considerable cost. The greater the number of replacements retained, the fewer the number of animals available for sale, and the greater proportion of the farm that must be allocated to rearing replacements at the expense of carrying more productive ewes. As selection occurs in stud flocks, Sheep Improvement Ltd. (SIL) developed an exit fate recording system that distinguishes between commercial culls of unsound sheep and the culling of sound sheep based on knowledge such as pedigree or genetic merit that would not usually be available to commercial breeders. Ewes culled for commercial ... continued

Genetic and phenotypic relationships among flystrike indicator traits in the Earnscleugh stud Merino flock - Scobie DR; Hickey SM; Campbell AK; Maslen DP (Proceedings of the New Zealand Society of Animal Production, 2012)
Increases in breech wrinkles, breech cover and dags have been shown to increase flystrike susceptibility of Merino sheep. At shearing at approximately 320 days of age in 2007, 2008 and 2009, breech wrinkle (1 to 5), dag score (1 to 5) and breech cover (1 to 5) were scored on 736, 806 and 866 yearlings that were the progeny of 31, 38 and 36 sires respectively. It was hypothesised that flystrike would become worse with an increasing score, where 5 indicated a very wrinkly, very daggy or very woolly breech. Fleece weight was recorded at shearing and fleece midside samples were collected and measured for washing yield. Breech wrinkle score (h² = 0.25 ± 0.07), breech cover (h² = 0.33 ± 0.08) and dag score (h² = 0.10 ± 0.04) were found to be heritable. Breech wrinkle score and breech cover were phenotypically (0.39 ± 0.02, P < 0.05) and genetically correlated (0.40 ± 0.16, P < 0.05). Clean fleece weight was heritable (h² = 0.33 ± 0.06) and showed a strong significant negative genetic correlation (-0.52 ± 0.14, P < 0.001) with breech cover. There was no evidence of flystrike during the three years of investigation, but this stud could decrease susceptibility by decreasing breech cover, breech wrinkles and dag score

Genetic parameters for lactose and its relationship with concentrations and ratios of other milk components - Sneddon NW; Lopez-Villalobos N; Hickson RE; Shalloo L (Proceedings of the New Zealand Society of Animal Production, 2012)
The objective of this study was to estimate genetic parameters for milk yields, milk concentrations and ratios of milk components. Herd-test records from 268 Jersey cows from a Waikato dairy farm were obtained along with pedigree information. Genetic and phenotypic (co)variances for daily yields of milk (MY), fat (FY), protein (PY), milksolids (MSY; FY + PY) and lactose (LY), percentages of fat, protein, and lactose, and ratios of protein to fat (P:F) and protein to protein plus lactose (P:PL), and somatic cell score, were obtained with single trait and bivariate animal models using a restricted maximum likelihood methodology. The models included the fixed effects of month of calving and days in milk, modelled using an exponential curve, lactation number and the random effects of animal and cow permanent environment effects were also included in the model. Heritability estimates were 0.50 ± 0.12 (standard error) for MY, 0.25 ± 0.10 for FY, 0.30 ± 0.12 for PY, 0.27 ± 0.11 for MSY, 0.50 ± 0.12 for LY, 0.24 ± 0.04 for P:F ratio and 0.53 ± 0.04 for P:PL ratio. The genetic correlations for daily yields were high and positive. The genetic correlation between MSY and P:F ratio was -0.35 indicating that increases in MSY under the current breeding objective will decrease the P:F ratio, thus departing from an optimal ratio for whole milk powder processing.

Genetically, Merino ewes that lose less live weight during joining have a higher chance of having lambs but the total weight of the born lambs is not affected - Rose G; Mulder HA; van der Werf JHJ; Thompson AN; Ferguson MB; van Arendonk VAN (Proceedings of the New Zealand Society of Animal Production, 2012)
Sheep in many areas of Australia and New Zealand experience periods of variable feed supply. Merino sheep can be bred to be more resilient to this varying feed supply. Resilient sheep lose less live weight when grazing poor quality pasture. However, we do not know if breeding for live weight change genetically affects reproduction. To estimate genetic correlations between live weight change and reproduction we used information from 6,870 fully pedigreed Merino ewes aged two- to four-years-old. Liveweight change was measured during joining (42 days) on low quality pasture and during lactation (130 days) on high quality pasture. Reproduction traits were total weight of lambs born and weaned and binary traits of whether or not a ewe gave birth to, or weaned, a lamb. Genetic correlations between live weight change and reproduction within age were estimated. There were moderate to high genetic correlations between live weight loss during joining and the chance of having and weaning a lamb. All other correlations were low. Therefore, change in live weight during joining affects the chance of having a lamb but not the weight of those lambs.

"Grass to milk" and beyond - Macmillan KL; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2012)
Dr C.P. McMeekan’s book, "Grass to milk", has been used as the basis of this paper. It is an historical account of a dairying system based on cows harvesting improved pastures in situ following a seasonally concentrated calving in the late winter. It was published in 1960, not as a text book, but as McMeekan’s "complete philosophy of New Zealand dairy farming". The book’s contents present an opportunity to compare "performance" statistics for the described dairying system with those recently published in the peer reviewed literature and elsewhere. Commendable advances have been made in cow yield per lactation and feed conversion efficiency as well as in dry matter harvested per hectare. However, these advances have been partly offset by an increase in cow wastage, largely due to lower reproductive performance, even in research herds, in spite of interventions such as induced calving and treating anoestrous cows. What should be obvious from reviewing the seminal publication of McMeekan is that most of the management concepts described by McMeekan have stood the test of time and are as relevant today as they were 50 years ago.

Grazing behaviour of dairy cows on simple and diverse swards in summer and autumn - Bryant RH; Miller ME; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2012)
Increasing the proportion of dicotyledonous species such as herbs and legumes in dairy pastures may increase herbage dry matter intakes through ease of prehension. Simple swards consisting of either standard perennial ryegrass, high sugar ryegrass or tall fescue cultivars with white clover were established at the Lincoln University research dairy farm. Diverse swards were created by adding chicory and plantain to all mixtures, plus prairie grass and red clover to the perennial ryegrass, and praire grass and lucerne to the tall fescue. Grazing behaviour of cows during a two hour grazing session was monitored in summer and autumn. In summer, Diverse swards had a greater compressed sward surface height, lower mass and bulk density. Cows grazing Simple swards achieved a greater bite rate (49.3 vs 43.8 bites/min respectively (P < 0.05)). In autumn, all pasture swards had lower mass and contained a higher proportion of grass species than in summer. Bite rate was greater on Diverse compared with Simple swards (60.3 vs 54.3 bites/min respectively (P < 0.05)). Lower bite rate on Simple swards was compensated for by increasing grazing duration (P < 0.001). Sward type influenced bite rate adaptations.

Heritability and repeatability of resistance to nematode parasites in commercial beef cattle - Morris CA; Amyes NC (Proceedings of the New Zealand Society of Animal Production, 2012)
Faecal egg count (FEC) is used commonly as a guide to nematode parasite burdens in animals in vivo. The objective of this study was to estimate the heritability and repeatability of FEC in commercial beef calves, along with breeding values for FEC in the calves and their sires, for future quantitative and molecular analyses. In 2008-2011, faecal samples from 4,621 weaned beef calves were obtained for FEC1 from 11 herds (mainly Angus or Hereford). FEC1 represented the first sample after weaning generally between May and July); a second sample (for FEC2) was taken by September from all calves in some herds, with FEC1 and FEC2 samplings separated by an effective anthelmintic drench. Calves were sired by a total of 325 and 57 separate Angus and Hereford sires, respectively. Heritability estimates for loge(FEC+50) in Angus at Times 1 and 2 were 0.28 ± 0.05 (standard error) and 0.11 ± 0.09, respectively, with a genetic correlation of 0.89 ± 0.22 between them. Treating FEC1 and FEC2 as repeated measurements of the same trait, the repeatability estimate for loge(FEC+50) was 0.38 ± 0.04. The parameters estimated for loge(FEC+50) in weaned beef calves under commercial grazing conditions were similar to those from experimental beef calves.

Host-defence related bioactive proteins in cows’ milk during mastitis and after drying-off - Backmann EC; Hine BC; Broadhurst; Kim K; Smolenski GA; Stelwagen K; Wheeler TT (Proceedings of the New Zealand Society of Animal Production, 2012)
Besides the caseins and major whey proteins, cows’ milk contains a wide range of less abundant proteins that have functions associated with host defence, and are thought to play a role in protection against microbial infections (Stelwagen et al. 2009; Wheeler et al. 2007). Microarray analysis has shown that complex changes in gene expression occur in the bovine mammary gland in response to drying-off, including up-regulation of host-defence associated genes (Singh et al. 2008). The abundance of at least some proteins encoded by these genes can be altered in response to milking frequency and at different stages of the lactation cycle.

Identification of cost-effective management options for reducing greenhouse gas emissions by 10% on a dairy farm in Waikato, New Zealand - Adler AA; Doole aj Romera GJ; Beukes PC (Proceedings of the New Zealand Society of Animal Production, 2012)
An optimisation model of a dairy farm was built to estimate the cost of mitigation of greenhouse gas emissions (GHG-e). First, the Farmax and Overseer models were used to describe production, profitability, and emissions to the environment of a medium-input dairy farm system for the Waikato-Bay of Plenty region of New Zealand. This process allowed generation of a valid and consistent set of input data for a detailed nonlinear programming model able to optimise resource use. The optimisation model was then used to investigate how producers may best respond to the introduction of a 10% restriction on GHG-e, with and without the use of strategic changes to their farm system to mitigate GHG-e. Profit decreased by 8% when the restriction was introduced without the availability of strategic mitigation options. The variables that changed most to achieve the reduction were nitrogen fertiliser input, which was reduced by 58%, and stocking rate which was reduced by 7%. In contrast, profit increased by 5% when strategic mitigation options were used under GHG-e restrictions. Using high genetic merit cows was enough to achieve this increase in profit under the emissions constraint.

Impacts of different forages and packaging conditions on colour and lipid oxidation stability of lamb loins - Kim YHB; Stuart AD; Rosenvold K; Maclennan G (Proceedings of the New Zealand Society of Animal Production, 2012)
Fresh meat colour is one of the most important quality attributes that affects the consumer’s meat purchasing decisions (Renerre & Labas 1987). A number of factors such as feed type, animal breed, age, sex, display and packaging conditions influence the rate of metmyoglobin formation. Metmyoglobin is the pigment responsible for brown colour on meat surface during retail display ... continued

In vitro evaluation of the antimicrobial effects of chitosan against bacteria involved in ovine footrot - Mros S; Ali MA; Ghosh A; El-din Bekhit A; McConnell M (Proceedings of the New Zealand Society of Animal Production, 2012)
Virulent footrot of ovines is caused by a mixed infection of Dichelobacter nodosus and Fusobacterium necrophorum; anaerobic, non-spore forming Gram negative bacilli. Footrot has a significant economic impact on the farming industry within New Zealand (Hickford et al. 2005). When the interdigital skin of the ovine foot is damaged, or wet for a prolonged period, it may be infected by F. necrophorum, a member of the gut flora, which causes ovine interdigital dermatitis. The skin becomes red and swollen and bacterial toxin production results in necrosis in the upper layers of the skin enabling D. nodosus to establish if the organism is present in the flock or the environment. ... continued

In vitro fermentation of [15N-] ryegrass and ruminal digesta of sheep grazing a ryegrass-based pasture in the morning or in the afternoon - Vibart RE; Tavendale MH; Burke JL; Pacheco D (Proceedings of the New Zealand Society of Animal Production, 2012)
Sheep in many areas of Australia and New Zealand experience periods of variable feed supply. Merino sheep can be bred to be more resilient to this varying feed supply. Resilient sheep lose less live weight when grazing poor quality pasture. However, we do not know if breeding for live weight change genetically affects reproduction. To estimate genetic correlations between live weight change and reproduction we used information from 6,870 fully pedigreed Merino ewes aged two- to four-years-old. Liveweight change was measured during joining (42 days) on low quality pasture and during lactation (130 days) on high quality pasture. Reproduction traits were total weight of lambs born and weaned and binary traits of whether or not a ewe gave birth to, or weaned, a lamb. Genetic correlations between live weight change and reproduction within age were estimated. There were moderate to high genetic correlations between live weight loss during joining and the chance of having and weaning a lamb. All other correlations were low. Therefore, change in live weight during joining affects the chance of having a lamb but not the weight of those lambs.

Maintenance energy requirements of non-lactating, pregnant dairy cows - Mandok KS; Greenwood SL; Kay JK; Crookenden M; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2012)
A number of estimates of metabolisable (ME) and net energy (NE) requirements for maintenance, activity, reproduction and productive purposes have been published (AFRC 1995; ARC 1980; CSIRO 2007; NRC 2001). The most appropriate recommendations for New Zealand systems have been compiled by Nicol & Brookes (2007).

Milk somatic cells are not suitable biomarkers of lactating ruminant mammary gland function - Sciascia Q; Pacheco D; Senna Salerno M; Blair HT; McCoard SA (Proceedings of the New Zealand Society of Animal Production, 2012)
Understanding the molecular regulation of milk production by the ruminant mammary gland may help farmers meet increasing production milestones. Investigating these mechanisms currently relies upon invasive sampling by post-mortem or biopsy. The objective of this study was to determine if milk somatic cells, shed by the gland during milking, could be used as a non-invasive source of cells to measure these mechanisms. To answer this we employed two widely used molecular techniques, biochemical indices and quantitative polymerase chain reaction (qPCR). Experiment 1: Biochemical indices as measures of cell size, protein production capacity and efficiency were determined in milk somatic cells and mammary tissue harvested from six lactating dairy goats. Results showed protein production capacity (P = 0.03) and cell size (P = 0.03) were higher in mammary tissue compared to somatic cells while protein production efficiency was unaffected (P = 0.55). Experiment 2: Milk protein and ribosomal RNA gene expression were measured using qPCR in milk somatic cells and mammary tissue collected from three lactating dairy cows treated with growth hormone and four treated with saline. Results showed expression of all genes differed between milk somatic cells and mammary tissue. Taken together, these results indicate milk somatic cells are not suitable for measuring biochemical indices or gene expression in the lactating ruminant mammary gland.

Once-daily milking during a feed deficit improves energy status in early lactating dairy cows - Kay JK; Phyn CVC; Rius AG; Morgan SR; Grala TM; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2012)
The aim of this study was to determine the effect of once-daily (1X) milking during a feed deficit on energy status of grazing dairy cows. Multiparous cows (n = 120), grazing to residuals of 1,600 kg DM/ha, and milked twice-daily (2X) from calving until approximately 35 days-in-milk, were allocated to one of four treatments in a 2 x 2 factorial arrangement. Cows were adequately fed (14 kg DM/cow/d) or underfed (8 kg DM/cow/d) and milked 2X or 1X for three weeks, after which all cows were milked 2X and grazed to residuals of 1,600 kg DM/ha for 20 weeks. During the three-week treatment period, plasma concentrations of glucose, insulin and insulin-like growth factor-I (IGF-I) were less in underfed compared with adequately cows, while non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHBA) and liver enzymes were greater. An interaction existed and the increase in liver enzymes with underfeeding only occurred in cows milked 1X. Cows milked 1X had greater plasma glucose, insulin and IGF-I and less NEFA and BHBA than those milked 2X. Data indicate that milking cows 1X during an acute feed deficit improves energy status.

Is placentome size more important than morphologic type in relation to fetal weight in sheep? - van der Linden DS; Sciascia Q; Sales F; McCoard SA (Proceedings of the New Zealand Society of Animal Production, 2012)
In sheep, placental exchange of nutrients between the ewe and her fetus occurs at sites called placentomes (Ford 2000). Placentomes are comprised of cotyledons on the chorioallantoic membrane which attach to discrete caruncles on the uterine wall (Ford 2000). Ovine placentomes can be classified into four types on the basis of their gross morphological appearance (Vatnick et al. 1991). The distribution of placentome type and size of individual placentomes can be influenced by many factors such as, nutritional state, placental blood flow and oxygen availability (Gardner et al. 2002; Osgerby et al. 2004). In general, previous work has shown that adverse intrauterine conditions early in pregnancy lead to a shift to more everted placentomes (more C and D types) (Osgerby et al. 2004; Vonnahme et al. 2006).

Potential for genomic selection of bovine embryos - Fisher PJ; Hyndman DL; Bixley MJ; Oback FC; Popovic L; McGowan LT; Berg MC (Proceedings of the New Zealand Society of Animal Production, 2012)
Sexual reproduction is a genetic lottery. There is no guarantee that offspring receive a favourable combination of genes from their parents to form their genotype. For animal breeding, the conventional way of selection has been based on phenotyping adults or their progeny. Increasingly, however, dairy cattle breeding schemes are integrating the use of genomic selection of juvenile and adult candidates (Hayes et al. 2009; Pryce et al. 2010). To further increase the intensity of selection and accelerate the rate of genetic gain, we aim to genomically select bovine embryos within one week after in vitro fertilisation (IVF) using gametes from elite parents. The generation of multiple embryos from multi-factorial ... continued

Preliminary examination of wastage in Thoroughbred and Standardbred horses in New Zealand using training milestones - Tanner JV; Rogers CW; Bolwell CF; Gee EK (Proceedings of the New Zealand Society of Animal Production, 2012)
The production of Thoroughbred and Standardbred horses to race is a multi-million dollar industry in New Zealand. However, wastage studies have shown that as many as 50% of foals born fail to race (Wilsher et al. 2006; Jeffcott et al. 1982; Perkins et al. 2004a; Perkins et al. 2004b). Wastage, defined as losses that occur during the production of horses to race, is a major cause for concern in the racing industry and has both animal welfare and economic implications. Wastage may be caused by several factors including lack of ability, physical injury or financial decision by owners and can occur at any stage from conception through to competing at the races. ... continued

Prenatal maternal effects on daughter milk production in New Zealand dairy cattle - Gudex BW; Johnson DL; Singh K (Proceedings of the New Zealand Society of Animal Production, 2012)
The impact of a cow's live weight and body condition score (BCS) during pregnancy on the milking performance of a resulting daughter was investigated using 4,021 Jersey and 9,329 Holstein Friesian dam-daughter pairs from the Livestock Improvement Corporation Sire Proving Scheme. Although the estimated maternal heritability of each trait in each breed was small (< 0.02), a l kg increase in dam weight was associated with 1.19 (± 0.25) and 0.43 (± 0.15) litres increase in daughter milk volume, a 61 (±11) and 15 (±6) gram increase in fat and a 55 (± 8) and 14 (±5) gram increase in protein in Jersey and Holstein Friesian cows respectively. A one unit increase in BCS was associated with an increase in volume by 32 (± 19) litres in Jerseys and a 14 (± 14) litre decrease in Holstein Friesians. Fat increased by 1.91 (± 0.84) kg and 0.56 (± 0.55) kg and protein increased by 1.64 (± 0.63) kg and 0.06 (±0.42) kg per unit BCS in Jersey and Holstein Friesian respectively. All daughter responses are per lactation. Although small changes in the daughters milking traits were observed, the lack of significant variation in the maternal heritability indicates that the sample size of the dataset may not be sufficient to detect if prenatal maternal effects truly exist.

Presidential Address 2011 - The changing face of agriculture - Greer AW (Proceedings of the New Zealand Society of Animal Production, 2012)
Agriculture is continually changing. For a large part change is essential, from the seasonal changes in animals and plants through to the inevitable changes in land use and labour requirements as technological improvements and market forces take effect. Indeed, things have changed somewhat since I was a young boy growing up on a farm in rural Southland. In my youth I would have had to travel for nearly an hour to the nearest dairy farm. But by the time I was at university, about ten years ago, the district had started to ... continued

Productivity and financial characteristics of herds that produce milkfat with different concentration of unsaturated fatty acids using a stochastic farm model - Silva-Villacorta D; Lopez-Villalobos N; Blair HT; Hickson RE; MacGibbon AKH (Proceedings of the New Zealand Society of Animal Production, 2012)
The objective of this study was to describe the characteristics of dairy farms with different concentrations of unsaturated fatty acids (UFA) in milkfat using a stochastic farm model. Daily phenotypic cow performance was simulated using an exponential function including terms for milk, fat, protein and live weight, and a third order orthogonal polynomial of milkfat UFA concentration. Daily and yearly feed requirements were estimated from metabolisable energy requirements for maintenance, lactation, pregnancy and growth. Two groups of farms were simulated: (1) Average UFA farms (30 farms, milkfat UFA concentration = 30.04 g/100g milkfat) and (2) High UFA farms (30 farms, milkfat UFA concentration = 35.99 g/100g milkfat). Each farm was 140 ha and had 386 cows, a replacement rate of 18% and a spring calving between 20 July and 10 September. The simulation was replicated 1,000 times. High UFA farms produced significantly (P < 0.05) less milkfat (338 vs 502 kg/ha) and milksolids (692 vs 927 kg/ha) than Average UFA farms. This resulted in High UFA farms having lower (P < 0.05) gross farm income ($3815 vs $5075 /ha) and cash operating surplus ($-331 vs $598/ha) than Average UFA farms. This highlights the need to develop a payment system that rewards concentration of UFA in milkfat.

The random bouncing ball - Nicol AM (Proceedings of the New Zealand Society of Animal Production, 2012)
A retrospective, biased, personal review of a contribution to animal production research. The review covers aspects of animal behaviour; maternal behaviour, and deer behaviour. It recalls studies on the effect of the heat of warming feed on the lower critical temperature of ruminants and summarises more recent studies on analgesia of the antlers of yearling stags. A significant proportion of the review revolves around work in grazing ecology mainly mixed animal species grazing. Deer are equivalent to sheep in grazing around cattle dung pats; goats have a similar dietary preference for clover as sheep unless the clover is short; cattle are disadvantaged when continuously grazed with sheep, but not with rotational grazing; diet composition is markedly affected by mixed grazing.

The relationship between milk synthesis and intracellular profiles of amino acids in the bovine mammary gland - McCoard SA; Pacheco D; Treloar BP; Wards N; Swanson K; Singh K (Proceedings of the New Zealand Society of Animal Production, 2012)
There is a growing body of evidence that amino acid (AA) signalling in the mammary gland may play a key role in milk production of ruminants through modulation of translational regulation (Moshel et al. 2006; Toerien & Cant 2007). It has been postulated that the effect of nutrient signalling on elements of translational control of milk protein synthesis may contribute to the variable responses of milk protein yield observed following nutritional perturbations (Hanigan et al. 1998). Consistent with this hypothesis, we have reported that changes in the mean and variance of intracellular free AA (FAA) in the bovine mammary gland are associated with ... continued

Relationship between profiles of free amino acids in fetal and maternal plasma with those in skeletal muscle, in twin and single fetuses from ad-libitum fed ewes in late gestation - Sales FA; Treloar BP; Pacheco D; Blair HT; Kenyon PR; Nicholas G; Senna Salerno M (Proceedings of the New Zealand Society of Animal Production, 2012)
Skeletal muscle growth depends on amino acid (AA) availability, not only as building components, but also as regulatory signals for protein accretion (Wu 2009). However, their signalling role for muscle growth in ruminants is poorly understood. We have previously reported that lower muscle weight in twin compared to single fetuses in late gestation, is associated with changes in the profile of specific intracellular muscle free AA (FAA), when ewes are fed a maintenance plane of nutrition during gestation (Pacheco et al. 2010a). This suggests that some AA may regulate muscle growth during fetal life.

Relative performance of Wiltshire and Perendale sheep - Sumner RMW; Scobie DR; O’Connell D; Henderson HV (Proceedings of the New Zealand Society of Animal Production, 2012)
Performance data are reported for flocks of Wiltshire and Perendale sheep grazed together for four years on a North Island hill country property (Whatawhata) and for four years on a South Island breeding/finishing property (Winchmore). Wiltshire ewes were lighter than Perendale ewes post-joining at Whatawhata, and at weaning at Winchmore. Greasy fleece weights of the Wiltshire and Perendale yearlings were 0.8 and 2.2 kg respectively, and 0.5 and 3.3 kg respectively for the ewes. As a result of a confounding effect of fibre shedding between day length and date of shearing, Wiltshire ewes exhibited a linear decrease in harvested fleece weight from the yearling stage whereas Perendale ewes showed a curvilinear age effect, with a maximum fleece weight at three to four years of age. Wiltshire ewes had a significantly lower reproductive rate, and lamb survival than Perendale ewes at both locations, with reproductive rate, fertility and litter size increasing significantly following the transfer of the flocks from Whatawhata to Winchmore. While there was no significant difference in the total weight of lambs weaned by the two breeds at each location, the loss in wool production would be compensated by lower shearing and management costs for Wiltshire sheep that shed completely.

Rumen fermentation characteristics are influenced by feeding frequency in sheep fed forage chicory and perennial ryegrass at two feeding levels - Sun XZ; Pacheco D; Hoskin SO; Luo DW (Proceedings of the New Zealand Society of Animal Production, 2012)
The objective of this study was to investigate the effects of feeding frequency and level of intake on rumen fermentation parameters of sheep fed chicory or perennial ryegrass. Fresh, vegetative chicory or perennial ryegrass were fed twice daily at 0900 h and 1630 h in the first period, and hourly in the second period to eight rumen-fistulated wethers at 1.3 and 2.2 times their maintenance metabolisable energy requirements. Rumen fluid pH, ammonia and volatile fatty acid (VFA) concentrations at 0900, 1000, 1100, 1200, 1300 and 1500 h were determined. When fed hourly (P < 0.05), but not twice-daily, forage type and feeding level significantly affected rumen pH. Differences in total VFA concentrations between forages and feeding levels were influenced by feeding frequency. Ammonia concentrations were always lower in sheep fed chicory than ryegrass (P = 0.001). Differences in rumen pH, ammonia and total VFA concentrations attributed to either forage species, level of intake or their interactions and were more likely to be detected when sheep were fed hourly, compared to twice-daily, as a result of the reduction in diurnal variation of these parameters. Manipulation of feeding frequency and/or feed intake can modulate the responses of ruminal metabolism to fresh forage diets.

The use of milking intervals of individual cows in assessing herd test milk production data - Molenaar AJ; Henderson HV; ML Burgess; Burgess WG; Johnson DL; Singh K (Proceedings of the New Zealand Society of Animal Production, 2012)
Herd testing is a significant expense for dairy farmers but it gives important information about individual cow yields and contributes to the genetic worth status of the cows. While every effort is made to maximise the value of the tests to the farmer there are still opportunities to increase this value further. Estimations of milk yield from herd tests, whether from one or two milkings, rely on the generally held assumption that animals come in to the parlour in a similar order at each milking (DairyNZ 2011) and so the values obtained reflect a nominal 24 hour yield. ... continued

Use of progesterone profiling to investigate factors affecting conception rates in a large, pasture-grazed dairy herd - Burke CR; Meier S; Pellow R (Proceedings of the New Zealand Society of Animal Production, 2012)
A study was conducted at the Lincoln University Dairy Farm to investigate factors influencing conception rate (CR). Relative to the planned start of mating date (Day 0), milk progesterone (MP4) concentrations were determined weekly from Day -20 to 0, twice weekly from Day 0 to 42, and then weekly to Day 70 in 666 cows. Trough-like patterns among individual profiles were identified and defined as periovulatory events. Pre-mating ovulatory status was a predictor (P < 0.01) of first service CR (FSCR), with anovulatory cows having a lower FSCR (37.4%) compared with ‘late’ (47.3%) and ‘early’ (56.4%) ovulating cows. In turn, interval from calving to Day 0 was a significant determinant for pre-mating ovulatory status. Oestrus detection was performed to a high standard, even though 5% of the 850 artificial inseminations were coincident with a lack of ovulation. MP4 profiles also indicated that 4% of cows that conceived during the 37-day artificial breeding period subsequently lost these pregnancies. A 2.6% error rate for diagnosing pregnancies on Day 78 was detected, mostly due to incorrectly attributing pregnancies following artificial breeding. Findings indicate the critical importance of managerial strategies that promote a high prevalence of cows having ovulated at least 21 days before mating starts.

Validation of a bio-economic dairy production model - Visser A; Lopez-Villalobos N; Morel PCH (Proceedings of the New Zealand Society of Animal Production, 2012)
DairyMax is an internet-based bio-economic dairy production model that uses a deterministic cow model to establish response curves of milksolids (MS; fat plus protein) production to energy intake at different stages of lactation and nutrient requirements for different levels of production. Another component in DairyMax is a linear programming module that uses farm-related constraints, market prices for supplements, cost of pasture and silage production and cow-related constraints to optimise a feeding strategy based on a maximum profit algorithm. The objective of this study was to validate the cow model of DairyMax against published field work conducted in New Zealand. In DairyMax, the stocking rate was adjusted to get the same MS production as in the experiment. The dry matter intake (DMI) associated with the different production levels were compared assuming energy content of 11.2 MJ ME/kg dry matter, similar to that reported in a three-year field experiment. The ability of the model was satisfactory in predicting yearly DMI per cow (Concordance correlation coefficient = 0.98). Productive performance, DMI and feed conversion efficiency (ratio between DMI and MS) of dairy cows under different stocking policies can be predicted by DairyMax with satisfactory accuracy.

Variation of milk composition traits among Holstein-Friesian-sired cows - Cullen NG; Hickey SM; Morris CA (Proceedings of the New Zealand Society of Animal Production, 2012)
A pooled afternoon and morning milk sample was obtained from each of 3,789 cows of known pedigree during a standard herd-test carried out in 21 North Island spring-calving herds between November and February. The cows were all sired by one of 11 Holstein-Friesian bulls, in a sampling design intended to sample milk from many daughters per sire, for segregation studies. Routine herd-test data consisted of 24 hour milk yield, protein %, fat % and somatic cell count. Samples were measured at Ruakura for fatty acid composition, fat melting point, and the concentrations of the following components, lactoferrin, β-lactoglobulin, β-casein, κ-casein, and total carotenoids. After liaison between AgResearch Ruakura staff and each dairy farmer a variate describing the current grazing groups of cows were included in analyses. Coefficients of variation were calculated for each milk component, and ranged from 0.04 to 0.35. Phenotypic correlations among components were estimated. The correlations were negative between the percentage of mono-unsaturated fatty acids present in milkfat and both the protein % (-0.26 ± 0.03 (standard error)) and fat % (-0.38 ± 0.02) of the milk. Some implications of selection mainly for yield from cows at pasture are discussed in terms of likely effects on milk composition.

Weight management considerations prior to mating to control litter size in Inverdale ewes - Smaill B; Juengel JL; Davis GH; Demmers KJ (Proceedings of the New Zealand Society of Animal Production, 2012)
Nutritional flushing of ewes prior to mating is a routine component of many commercial farming operations to maximise profitability by increasing the number of lambs born per ewe. In the 1990s, the Inverdale mutation ... continued

Animal welfare policy and science - keeping up with a changing world - O’connor CE; Littin KE (Proceedings of the New Zealand Society of Animal Production, 2011)
New Zealand’s animal welfare laws and policies are backed by sound animal welfare research that is internationally recognised for its quality. Indeed, the Animal Welfare Act 1999 requires scientific knowledge to be considered in the development of animal welfare standards in codes of welfare. Research needs are identified and prioritised to meet the requirement for scientific knowledge. However, animal welfare also requires a consideration of societal views, good practice and available technology. Can research also help in the consideration of these other factors? Here we consider these issues in the wider context of applying science to policy development under changing societal expectations.

The apparent digestibility of palm kernel expeller (PKE) consumed by pasture-fed sheep - Burke JL; Dias FN; Pacheco D; Lopez-Villalobos N; Holmes CW (Proceedings of the New Zealand Society of Animal Production, 2011)
Palm kernel expeller (PKE) usage in New Zealand has increased despite little being known about its nutritional role as a supplement in pasture based diets. The chemical composition of PKE is often reported in New Zealand, but the digestibility is not. A digestibility study was conducted with twenty four lambs fed one of four different amounts (0, 15, 30 or 45%) of their dry matter (DM) intake as PKE, plus molasses pellets (PKEM; 90% PKE and 10% molasses) with the remainder of the diet being fresh pasture. Sheep were fed at either maintenance or ad libitum during two experimental periods, that differed in pasture quality. Digestibilities were extrapolated linearly to estimate digestible energy concentration and the apparent digestibility of DM, crude protein, neutral detergent fibre and gross energy at any intakes for a diet consisting of 100% PKEM. Overall, the estimated apparent digestibility of DM, crude protein, neutral detergent fibre and gross energy for PKEM at intakes of 670 and 1,214 gDM/lamb/day were 63.0, 52.0, 67.0 and 64.0%, respectively. The values estimated for digestible energy concentration (MJ/kgDM) of PKEM ranged between 12.4-12.7, from which values for metabolisable energy concentration of 10.2 and 10.5 MJME/kgDM could be calculated.

Are high breeding worth index cows more feed conversion efficient and nitrogen use efficient? - Woodward SL; Waghorn GC; Bryant MA; Mandok K (Proceedings of the New Zealand Society of Animal Production, 2011)
Future dairy farming in New Zealand will require increases in milksolids production and reduced impact on the environment. Cows which are more feed conversion efficient (FCE) and nitrogen use efficient (NUE) will help achieve these targets. In March 2010, eight High breeding worth (BW = 198), High production worth (PW = 319) and eight Low BW (57) PW (10) cows were housed in metabolism stalls and fed low quality perennial ryegrass-based herbage (metabolisable energy = 9.87 MJ/kg DM; crude protein = 15.2 g/100g DM). High BW cows had higher dry matter intakes (DMI) (16.0 vs 14.8 kg DM/cow/d, P <0.05) and produced more milksolids (1.32 vs 1.03 kg MS/cow/d, P <0.001). Due to their higher DMI, the High BW cows also had a higher feed N intake than the Low BW cows (388 vs 360 g N/cow/d, P <0.05), and partitioned more of their intake N to milk (22.0 vs 18.5 %, P <0.01) and less to urine (39.7 vs 46.2%, P <0.01). Overall, the High BW cows were more FCE (82.7 vs 70.2 g MS/kg DMI, P <0.01) and more NUE (22.0 vs 18.5 %, P <0.01) when fed low quality herbage in late lactation.

The association of ewe body condition score with weight of lamb weaned - Mathias-Davis HC; Shackell GH; Greer GJ; Everett-Hincks JM (Proceedings of the New Zealand Society of Animal Production, 2011)
Data from 1,301 ewes lambing in 2009 were analysed to investigate the association of body condition score (BCS) with total lamb weaned (TLW). BCS was assessed on a scale of 0-5 at mating (BCSM), scanning (BCSS), pre-lambing (BCSL) and weaning (BCSW) and categorized as <3, 3-3.5 and >3.5. Ewe age, flock, live weight at mating (LWM) and date of lambing (DOB) had significant effects on TLW (P <0.05). Ewes having triplets at birth with >3.5 and 3-3.5 BCSM had a higher TLW (63.2, 63.0 kg respectively; P<0.05) than ewes with triplets at birth and <3 BCSM (56.1 kg). Ewes with 3-3.5 BCSS had higher TLW than ewes with >3.5 BCSS for all birth ranks (49.8 kg, 47.2 kg respectively, P <0.05). There was no association between BCSL and TLW. Ewes with <3 or 3-3.5 BCSW had a significantly higher TLW than ewes with >3.5 BCSW (>3.5 = 43.8 kg, 3-3.5 = 48.9 kg, <3 = 50.9 kg; P <0.001). This study indicates ewes with 3-3.5 BCSS or <3 or 3-3.5 BCSW outperform ewes with >3.5 BCSS or >3.5 BCSW.

BRIEF COMMUNICATION: Arapawa: a novel New Zealand sheep breed of distinct origin - Young EA; Kijas JW; Mcculloch R; Scobie DR; Mcrae KM; Pickering NK; Dodds KG; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2011)
Arapawa sheep are a feral breed found on Arapawa Island in the Marlborough Sounds, New Zealand. Their origin is not documented, but it is thought to be one of the oldest feral flocks in New Zealand dating back to approximately mid 1800s (Orwin et al., 1984). There are numerous... Continued

BRIEF COMMUNICATION: Comparison of the performance of dairy cows offered energy supplements prior to drying off and kale at high and low allowance during the dry period in winter - Greenwood SL; Dalley DE; Purdie NG; Rugoho I; Bryant RH; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2011)
Forage availability and body condition score (BCS) of the dairy cow are important aspects of dairy livestock management during the dry and peripartum period. New Zealand guidelines recommend a target BCS of 5.0 at calving (1-10 scale where 1 = Emaciated and 10 = Obese, Roche et al., 2009). Providing adequate forage to meet... Continued

BRIEF COMMUNICATION: DNA methylation patterns in bovine blastocysts suggest that only limited epigenetic reprogramming has occurred in the early embryo - Couldrey C; Wells DN; Lee RSF (Proceedings of the New Zealand Society of Animal Production, 2011)
Epigenetics is the study of changes in phenotype caused by mechanisms other than changes in the underlying DNA sequence. In agriculture, epigenetics largely resides in the environment component of the equation; Phenotype = Genotype + Environment. Epigenetic mechanisms include but are not limited to, DNA methylation, acetylation and... Continued

BRIEF COMMUNICATION: Effect of gender and prior exposure on the intake and preference of sheep for plantain post-weaning - Pain SJ; Kenyon PR; Morris ST; Kemp PD (Proceedings of the New Zealand Society of Animal Production, 2011)
Animals are exposed to a sensory learning environment both pre- and post-birth birth (Nicolaidis, 2008). Numerous experiments with rats (Smotherman, 1982), chickens (Porter & Picard, 1998; Sneddon et al., 1998) and sheep (Nolte et al., 1992; Schaal et al., 1995; Simitzis et al., 2008) have demonstrated prenatal... Continued

BRIEF COMMUNICATION: Effect of milking frequency and concentrate supplementation on milk production during an extended lactation in grazing dairy cows - Rius AG; Phyn CVC; Kay JK; Morgan SR; Grala TM; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Extending the lactation for longer than 300 days can be used to maintain a high level of milk production, improve reproductive function, and animal welfare. Extended lactations of ~600 days in milk (DIM) in pasture-based systems could benefit the dairy industry by maintaining a relatively constant milk supply throughout the season, improving labour conditions, and reducing on-farm costs (Kolver et al., 2007). Milk production during an extended lactation is dependent... Continued

BRIEF COMMUNICATION: Effect of red wine lees on lamb meat quality - Bekhit AED; Richardson A; Maclennan G; Lindsay S; Grant C (Proceedings of the New Zealand Society of Animal Production, 2011)
Oxidative processes in fresh red meat can cause detrimental effects on the keeping and eating qualities of meat as well as its nutritional value (Bekhit ± Faustman, 2005; Bekhit et al., 2007). Several supplement feeding strategies have been shown to improve the colour stability of fresh meat during display such as Vit E (Faustman et al., 1989) and condensed... Continued.

BRIEF COMMUNICATION: Effects of handling during calf rearing on behavioural and physiological responses of one year-old dairy heifers - Stewart M; Worth G; Webster JR; Schütz KE (Proceedings of the New Zealand Society of Animal Production, 2011)
Interaction with humans is a daily part of most farm animal’s lives. The nature of these interactions is an important factor contributing to animal welfare and productivity. Exposure to negative handling can increase fearfulness in animals, which can cause problems such as increased handling time, poor meat quality and... Continued

BRIEF COMMUNICATION: Evaluating rumen fluid from sheep and cattle as inoculum in a newly developed automated in vitro rumen batch culture system - Muetzel S; Hunt CL; Tavendale MH (Proceedings of the New Zealand Society of Animal Production, 2011)
In vitro rumen batch culture systems are widely used to rank feeds according to their rate of fermentation, potential gas production and in vitro digestibility. Their main advantage is that the analysis is quick and... Continued

BRIEF COMMUNICATION: Genomic selection in the New Zealand Sheep industry using the Ovine SNP50 Beadchip - Auvray B; Dodds KG; McEwan JC (Proceedings of the New Zealand Society of Animal Production, 2011)
The Illumina OvineSNP50 BeadChip is a single nucleotide polymorphism (SNP) microarray targeting 54,241 evenly spaced SNPs on the sheep genome, developed by Illumina in collaboration with AgResearch, Baylor, UCSC, CSIRO, and the USDA as part of the International Sheep Genomics Consortium. It was used to genotype key... Continued

BRIEF COMMUNICATION: Liveweight gain of grazing dairy calves in their first season subjected to a targeted selective anthelmintic treatment (TST) regime - McAnulty RW; Gibbs SJ; Greer AW (Proceedings of the New Zealand Society of Animal Production, 2011)
For some time now it has been recognised that suppressive anthelmintic regimes select strongly for resistance (Jackson & Miller, 2006). However, despite widespread anthelmintic resistance on beef properties in New Zealand (Waghorn et al., 2006), little attention has been paid to the sustainability of anthelmintic practices in... Continued

BRIEF COMMUNICATION: Phenotypic selection of cows for lactation persistency - Hickey SM; Singh K; Morris CA; Henderson HV; Molenaar AJ (Proceedings of the New Zealand Society of Animal Production, 2011)
Lactational persistency is the degree to which early lactation yield persists during the lactation season. Though this is a desired dairy performance trait, it has not been directly selected for in New Zealand dairy populations. In spring-calving pasture-fed cows, peak lactation is reached soon after calving and then declines by about 10% per month (Davis et al., 2000) until the cows are... Continued

BRIEF COMMUNICATION: The effect of dam age and lamb birth rank on the growth rate, faecal egg count and onset of puberty of single and twin female offspring to 12 month of age - Loureiro MFP; Paten AM; Asmad K; Pain SJ; Kenyon PR; Pomroy WE; Scott I; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2011)
Breeding ewe lambs at eight to nine months of age has gained popularity on New Zealand sheep farms in recent years. This is predominantly because of the many production advantages it offers: greater net profits, increased number and weight of lambs produced per ewe productive lifetime, better use of spring herbage, early recognition of fertility potential, increased rates of genetic gain and... Continued

BRIEF COMMUNICATION: The effects of dam nutrition during pregnancy on the postnatal growth and puberty attainment of ewe progeny - Paten AM; Asmad K; Loureiro MFP; Kenyon PR; Pain SJ; Peterson SW; Pomroy WE; Scott I; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2011)
In New Zealand’s pastoral sheep-production systems, feed can become limiting during winter, when breeding ewes are pregnant. Ewes are often restrictively fed during early-gestation (Kenyon & Webby, 2007) to enable greater levels of nutrition in late-gestation. Many studies have demonstrated that dam nutrition during various stages of pregnancy can program the...

BRIEF COMMUNICATION: The effects of dam nutrition during pregnancy on the growth of male offspring - Asmad K; Paten AM; Loureiro MFP; Kenyon PR; Pain SJ; Parkinson TJ; Pomroy WE; Scott I; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2011)
During pregnancy, nutritional status of the ewe is crucial because of its potential effect on fetal development, subsequent lamb survival and reproduction post-birth (Rhind et al., 2001). Manipulation of the progress of fetal development can affect the structure and physiology of adult offspring through the process of fetal programming (Barker et al., 1993). Epidemiological data... Continued

BRIEF COMMUNICATION: The effects of different forage types on lamb performance and meat quality - Campbell AW; Maclennan G; Judson HG; Lindsay S; Behrent MR; Mackie A; Kerslake JI (Proceedings of the New Zealand Society of Animal Production, 2011)
Meat quality is made up of a number of traits, with colour at the point of purchase, being perceived as the main indicator of freshness. The traits of aroma, flavour, succulence, and texture influence the eating experience and the probability of repurchase. A number of factors influence meat quality traits, including environmental factors such as... Continued.

BRIEF COMMUNICATION: The influence of a herb and legume sward on maternal behaviour and lamb colostrum intake and thermoregulation - Hutton PG; Kenyon PR; Bedi MK; Kemp PD; Stafford KJ; West DM; Morris ST (Proceedings of the New Zealand Society of Animal Production, 2011)
Nutrition of the ewe in late pregnancy is known to affect colostrum production, lamb live weight, survival to weaning (Kenyon & Webby, 2007; Kerslake et al., 2009), and maternal behaviour (O’Connor et al., 1985). Kenyon et al. (2010) reported that offering a mixed herb sward containing... Continued

BRIEF COMMUNICATION: Voluntary food intake of pregnant and non-pregnant red deer hinds during the gestating period - Scott IC; Barrell GK; Asher GW; Yuan JV (Proceedings of the New Zealand Society of Animal Production, 2011)
Efficient venison production systems rely on maximum growth of deer calves before their first winter. This is facilitated by an early conception in March for an October/November calving so that the nutritional demands of lactating hinds and their offspring are better aligned with pasture growth and quality under New Zealand lowland farming conditions. However, Scott et al. (2008) have...

Can livestock production be increased without increasing greenhouse gas emissions? - Waghorn GC (Proceedings of the New Zealand Society of Animal Production, 2011)
More efficient farming practices will increase livestock production without increasing greenhouse gas (GHG) emissions. GHG emissions of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) have always been part of agriculture, but national and international concern about global warming has focused research towards their mitigation. CH4 production represents a loss of about 9% of metabolisable energy in feed, whilst N2O production represents a loss from excessive nitrogen (N) application. Mitigation should therefore provide benefits for farming by conserving dietary energy and reducing fertiliser costs. Unfortunately there are limited options for reducing CH4 loss. Nevertheless, by ensuring animals are productive and fertile and adopting management systems that ensure a high utilisation of feed grown, it is possible to lower CH4 emissions per unit of product. There are more opportunities for reducing N2O emissions, because these originate in large part from N fertiliser application, and more prudent use will lower costs, minimise nitrate leaching into waterways as well as lowering GHG emissions. Emissions per unit of product are termed emissions intensity. Application of current and new knowledge to agricultural systems will increase livestock production and lower emissions intensity whilst sustaining our ecosystem, but farmers will always need to address environmental issues.

The challenges of animal wintering from a sustainability perspective - Dalley DE (Proceedings of the New Zealand Society of Animal Production, 2011)
Winter represents an important time for South Island dairy herds. The task of improving body condition of cows during winter poses a number of challenges in this environment. Under current forage crop based wintering systems, many cows fail to achieve body condition score targets and there is increased potential for nutrient leaching and the loss of soil structure and health. In addressing the poor cow performance and to minimize the environmental impact of current systems, farmers are looking to alternative wintering systems. Consequently off-pasture systems to manage feed supply and provide shelter in winter are becoming more common to remove the need for grazing forage crops and limit effluent discharges into the environment. While many farmers have viewed such systems as a solution to their wintering issues, rapid implementation and lack of readily available information on best practice management has resulted in sustainability issues unique to these new systems. This paper examines the challenges of wintering in the southern South Island and outlines how the dairy industry is working to provide sustainable options for the future.

Continuing to increase productivity while maintaining our clean green image. Introductory remarks - Kerslake JI (Proceedings of the New Zealand Society of Animal Production, 2011)
An increase in intensive livestock farming can help our agricultural industry increase the production of more affordable food products. Unfortunately it can also have a negative impact on our environment and consequently the overall acceptance of our food products by the international consumer. To retain our position as leaders of premium quality agricultural food products, the New

Dairy goat production systems in Waikato, New Zealand - Solis-ramirez J; Lopez-Villalobos N; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2011)
Thirteen dairy goat farmers from the Waikato region of New Zealand were surveyed to describe and quantify the main features of their production systems. Twelve herds were maintained indoors and one herd was under grazing conditions, the latter farm was excluded from further analyses. All farms supplied milk to the Dairy Goat Cooperative (NZ) Ltd which produces milk powder for export. A total of 11 breed groups were identified. Out of the total milking does, Saanen was 88%, Toggenburg x Saanen 8%, Toggenburg 2% and others 2%. The average herd comprised 20% replacement kids, 17% does between 7 to 12 months-of-age, 59% does 1 to 10 years-old and 4% bucks. Culling of milking does was due to low production (35%), poor fertility (14%), leg problems (6%), mastitis (6%) and other reasons (13%), while 27% died between 1 to 10 years-old. Daily milk yield ± standard deviation per doe and per hectare were 2.8 ± 0.2 and 34.0 ± 3.7 kg respectively; while milk-solids were 0.32 ± 0.02 kg/doe and 4.10 ± 0.43 kg/ha, respectively, over a standardised 270 day lactation. Expenses were mainly feed concentrates (21.5%), dairy wages (20.3%), overheads (14.0%), family labour (14.5%) and other expenses (21.5%). The rates of return on investment were 10.2% and 10.7%, per milking doe and per hectare, respectively.

An economic appraisal of sex-sorted semen in New Zealand dairy herds - McMillan WH; Newman MG (Proceedings of the New Zealand Society of Animal Production, 2011)
An economic appraisal was undertaken of female enriched dairy semen in New Zealand commercial dairy cattle. Artificial insemination (AI) scenarios were evaluated in cows (C) and yearling heifers (H) with normal (N-) or sex-sorted semen (S-) with a female enrichment ratio leading to 75% (S75) or 90% (S90) heifer calves at birth. In-calf rates with S-semen were 0.75 of normal. Scenarios examined were: cows inseminated with N-semen and yearling heifers naturally mated (CN); cows inseminated with S-semen (CS75 and CS90); cows and yearling heifers inseminated with N-semen (CN-HN); and cows inseminated with N-semen and yearling heifers with S-semen (CN-HS75) and (CN-HS90). These scenarios required 29, 24, 19, 20, 19, and 17 days of AI in cows, respectively. S-semen reduced six-week in-calf rate and final calving rate. The total costs, including reproduction losses, semen and insemination, of producing a four-day old AI heifer replacement calf in a herd of 400 milking cows were $70, $262, $292, $69, $129 and $143. Maximum genetic gain in the milking herd is achieved using S90 semen in the highest genetic merit cows, although this is uneconomic at current semen prices. S-semen has a limited role in New Zealand dairy herds.

Economic evaluation of management strategies for a model Waikato farm to achieve a herd average body condition score of 5.0 at calving - Douglas RJ; Bryant JR; Hedley P; Smeaton DC; Brazendale R; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Industry advisers advocate a herd average body condition score (BCS) of 5 at calving to optimise profitability and system sustainability. However, the full value and cost of achieving the industry target has not been evaluated. Using the Farmax Dairy Pro model, the value of increasing the herd average BCS at calving from 4.0 to 5.0 was evaluated. A representative Waikato farm with a single dry off date in mid-May, with a herd average BCS of 4.0 at calving was modelled as the Base scenario. The profitability of seven alternative scenarios that achieved average herd BCS of 5.0 at calving were examined. Strategies that traded off autumn production to attain target BCS maintained a similar operating profit (OP) of -$46/ha to $3/ha, relative to the Base scenario. Partial season once-a-day milking increased OP by $220/ha to $269/ha, as long lactations and BCS targets were able to be achieved while reducing operating expenses. Additional supplements fed to dry cows to achieve target BCS increased OP by $43/ha. Additional mid-late lactation feeding increased OP by $139/ha to $269/ha, but only effected BCS by 0.15 units during lactation. These simulations indicate there is value in achieving recommended BCS targets, with multiple profitable strategies to do so.

The effect of carbohydrate type on milk and milk component yields in early lactation dairy cows - Higgs RJ; Sheahan AJ; Mandok K; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Providing additional energy to dairy cows in early lactation can increase energy intake, and improve production; however, different energy types may elicit different types of responses. The current study assessed the effect of supplementary feeding of starch, fibre, or sugar on milk and milk component yield. Sixty-eight dairy cows, due to calve over a 21-day period, were randomly assigned to one of four treatments at parturition (n = 17). Treatments consisted of a pasture-only control and pasture with starch, fibre or sugar based supplements. Supplements were formulated using the Cornell Net Carbohydrate and Protein System v6.1 and fed at an isoenergetic rate to supply sufficient metabolisable energy and protein to support a target of 30 kg of potential milk production, assuming cows would consume 13 kg of pasture DM/day; 11 MJ ME/kg DM. The study ran for eight weeks, and data were analysed on a week of lactation basis. Relative to the control, milk and milk protein yields were higher for the starch- and fibre-based supplements, but similar for the sugar (P <0.01). Protein yields were highest in cows supplemented with starch (P <0.001), while fat yields were numerically highest in cows supplemented with fibre. These data confirm that the form of carbohydrate fed affects the types of responses seen when supplementing concentrates in early lactation.

Effect of condensed tannins from Pinus radiata bark on Trichostrongylus colubriformis larvae and adult worms in sheep - Chan J; Waghorn GC; Molan AL; Brookes IM (Proceedings of the New Zealand Society of Animal Production, 2011)
A trial was undertaken to investigate the effect of condensed tannins (CT) extracted from pine (Pinus radiata) bark on gastrointestinal (GI) nematodes. Gastrointestinal parasitism is a significant cost to the sheep industry affecting health and productivity. Previous research has shown CT from some forage species can inhibit parasite egg hatching, larval development and reduce worm numbers in the GI tract. However, the forages containing CT tend to be less productive than ryegrass pasture, so this research investigated pine bark extract (PBE) which contains CT and is abundant in New Zealand, on Trichostrongylus colubriformis nematodes. In the in vitro incubations, 150 µg CT/ml prevented larval development and halved egg hatching. Effects of CT in vivo (35g/day) were evaluated using 12 wether sheep, fitted with abomasal cannulae and infected with T. colubriformis larvae. The sheep were either drenched at six hourly intervals or the PBE was infused into the abomasum over four days. Neither treatment affected faecal egg count (1,700/g faeces), egg hatching or development of eggs to L3 larvae. Lambs were slaughtered after four days of treatment. Nematode numbers were similar for all treatments (average 21,100/animal). Despite inhibitory effects on hatching and development in vitro, PBE had no anthelmintic benefits for the sheep and may reduce intakes.

Effect of lactation stage and breed on the concentration of unsaturated fatty acids in milkfat of New Zealand dairy cattle - Silva-Villacorta D; Lopez-Villalobos N; Blair HT; Hickson RE; Spelman RJ; Melis J; Davis SR; Berry SDK; Lehnert K; Snell RG (Proceedings of the New Zealand Society of Animal Production, 2011)
Milkfat composition influences the nutritional value and manufacturing characteristics of milk. This research studied the influence of: 1) stage of lactation on the concentration of unsaturated fatty acids (UFA) in milkfat of Holstein-Friesian, Jersey and Crossbred cows, 2) segregation of cows according to their UFA concentration in milkfat. The concentration of UFA in milkfat was predicted with a calibration equation using Fourier transform infrared spectroscopy. The data (21,757 test-day records) were analysed using a mixed model with a third-order orthogonal polynomial. In the three breeds studied, after early lactation the concentration of UFA in milkfat decreased steadily as the lactation progressed, but in Holstein-Friesian cows it increased slightly at the end of lactation. Throughout lactation, Holstein-Friesian cows produced milkfat with a higher concentration of UFA than Jersey and Crossbred cows. In each herd, cows were split into a high and a low group according to the average UFA concentration of the herd. The high UFA group had higher (P <0.001) milk yield, but lower (P <0.001) yields and concentrations of fat and protein than the low UFA group. This study indicates that concentration of UFA in milkfat is affected by breed and stage of lactation in New Zealand dairy cattle.

Effect of milking frequency and nutrition in early lactation on milk production and body condition in grazing dairy cows - Kay JK; Phyn CVC; Rius AG; Morgan SR; Grala TM; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Multiparous Holstein-Friesian cows (n = 120), grazing pasture and milked twice-daily (2X) from calving until ~35 days in milk, were allocated to one of four treatments. Treatments consisted of 2X or once-daily milking (1X), and UnRes (15 kg dry matter (DM)/cow/day) or Res (9 kg DM/cow/day) pasture intake for three weeks. Following treatment, all animals were milked 2X and offered pasture (residuals of 1,600kg DM/hectare) for 20 weeks. During the treatment period (Weeks 1-3), yields of milk, fat, protein and lactose decreased with reduced milking frequency and feeding level. Interactions existed for milk, protein and lactose yields and the decrease due to 1X milking was greater in the UnRes than Res cows. During the post-treatment periods (Weeks 4-12 and Weeks 13-23) no interactions were present. Restricted cows produced less milk, fat, protein and lactose compared with UnRes cows during Weeks 4-12, but no difference existed during Weeks 13-23. During Weeks 4-12, cows milked 1X produced less milk, fat, protein and lactose than those milked 2X and these differences remained during Weeks 13-23. During the treatment period, body condition score was less in Res than UnRes cows, however there was no effect of milking frequency on body condition score. Neither feeding level nor milking frequency altered post-partum anoestrus interval.

Effect of pre-grazing herbage mass on grazing behaviour, grass dry matter intake and milk production of dairy cows - Tuñon G; Lopez-Villalobos N; Kemp PD; Kennedy E; Hennessy D; O’donovan M (Proceedings of the New Zealand Society of Animal Production, 2011)
Identifying the optimum level of pre-grazing herbage mass (HM) across the grazing season is critical to maximising dry matter intake (DMI) and milk production from dairy cows. From 27 April to 17 October 2010, in Moorepark, Ireland, 45 Holstein-Friesian dairy cows (mean calving date 23 March 2010) were randomly assigned to Low (L), Medium (M) or High (H) pre-grazing HM treatments (targets 800, 1,500 or 2,200 kg DM/ha, above 4 cm, respectively) using perennial ryegrass-based pastures. Pre-grazing HM was determined twice weekly. Grazing behaviour was measured once and herbage DMI twice. Milk production was recorded daily. The experiment was divided into Period 1 (Mid-season; 27 April to 25 July) and Period 2 (Autumn; 26 July to 17 October). In the autumn, cows on L HM swards grazed for 90 minutes more and had 15% more grazing bites on a daily basis than did the cows on the other treatments. Cows grazing M HM swards tended to have highest DMI (L-15.2, M-16.5, H-15.7 kg DM/cow/day); while cows grazing H HM swards tended to have lowest milksolids yields (L-1.43, M-1.43, H-1.31 kg milksolids/cow/day). Pre-grazing HM levels of 2,200 kg DM/ha may impair DMI and milksolids production per cow, most likely due to decreased sward quality.

Effect of sub-clinical uterine infection on plasma amino acid concentrations in early lactation dairy cows - Lopdell T; Berg MC; Green MP; Back PJ (Proceedings of the New Zealand Society of Animal Production, 2011)
This study examined the effect of sub-clinical endometritis (scEndo) in early lactation on plasma amino acid (AA) concentrations of dairy cattle (n = 46). On D21 and D42 postpartum cows were classified as having scEndo or Clean based on uterine cytology; >18% polymorphonuclear (PMN) cells amongst uterine nucleated cells. On D21 and D42, 35% and 7% of cows respectively were classified as having scEndo, with a large proportion of scEndo cows having self-resolved the infection by D42. Plasma serine concentrations were higher (P <0.03) in scEndo compared to Clean cows irrespective of day postpartum. Independent of uterine status, three AA altered (P <0.05) in concentration between D21 and D42. The effect of change in uterine status from D21 to D42 resulted in decreased (P =0.05) concentrations of three AA in cows that resolved infection. The use of a lower cut-off to define scEndo (4% vs 18%PMN) identified four AA, instead of three AA at 18% that differed over time. Thus, during the early postpartum period, the concentrations of a number of AA change (P <0.05) irrespective of uterine health. However, scEndo is associated with an increase in plasma serine and a decrease in the concentration of several AA when a uterine infection is resolved.

Effect of temporary alterations to milking frequency during the early post-partum period on milk production and body condition score in grazing dairy cows - Phyn CVC; Kay JK; Rius AG; Morgan SR; Roach CS; Grala TM; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
This study investigated the immediate and long-term effects of temporary alterations to milking frequency post-partum in grazing cows. Multiparous Holstein-Friesian cows (n = 150) were assigned to one of five groups at calving: milked twice daily (2X, Control), or either once daily (1X) or thrice daily (3X) for three or six weeks, and 2X thereafter. During Weeks 1-6 post-calving, 1X for six weeks resulted in greater decreases in milk, fat, protein and lactose yields (P <0.05) relative to 2X than 1X for three weeks. Furthermore, 1X for three or six weeks reduced fat, protein and lactose yields (P <0.05), and tended to reduce milk yields (P = 0.08), for the remainder of lactation (Weeks 8-32). Body condition was greater for 1X cows at Weeks 6 and 8 (P <0.05) and tended to be greater during Weeks 8-32 (P = 0.09). Milking 3X for three or six weeks increased milk yield (P <0.05) relative to 2X during Weeks 1-6 and milk yields were numerically greater during Weeks 8-32 (P = 0.17); however, fat and protein yields were not affected. Once-daily milking for three or six weeks postcalving had lactation-long negative effects on milk production, whereas 3X increased milk yield but did not result in short- or long-term benefits in fat and protein yields.

The effect of three techniques of rumen pH assessment on measured pH of rumen fluid and digesta in an in vitro artificial rumen system - Broomfield AM; Gibbs SJ (Proceedings of the New Zealand Society of Animal Production, 2011)
Rumen pH assessment by three techniques was compared using an in vitro, artificial rumen system. Rumen digesta from dairy cows fed kale, fodder beet or ryegrass and clover pasture was used in an in vitro artificial rumen system. The digesta pH was measured by obtaining rumen fluid by centesis, by direct probe insertion, and by removal and filtration of fluid through cloth. This was done at different time intervals and at different heights from the base of the artificial rumen. There were significant differences in mean diet group pH. There was a significant difference between mean pH of all three techniques at the first time interval, and similarly between centesis and both the other techniques at the second and third time intervals. There was no significant difference between collection site height at any time interval. For dairy cows fed these forage diets, the technique of pH assessment of in vitro rumen digesta significantly influenced the pH measured, with centesis associated with higher mean pH than direct probe assessment. Given the importance of accurate rumen pH assessment, and the implications of differences between rumen fluid and rumen digesta pH in forage based ruminants, further research using the methodology with in vivo models is warranted.

Effect of wine lees on faecal egg count and lamb performance - Bekhit AED; Richardson A; Grant C (Proceedings of the New Zealand Society of Animal Production, 2011)
The potential anti-parasitic of lees from several wine varieties was investigated using an in vitro anthelmintic assay using Haemonchus contortus eggs. The most effective lees variety was further investigated in lambs in two trials. In Trial 1, 60 sheep was pasture grazed as one mob and allocated to one of three groups (n = 20): water drenched; drenched with the anthelmintic Matrix, and daily drenched with 100 mL/animal Pinot noir (PN) lees. In Trial 2, 80 lambs were grazed as one mob and assigned to four treatments (n = 20): Pasture only (Control); Pasture plus lucerne pellets; Pasture, lucerne pellets and drenched with Matrix; Pasture, lucerne pellets and wine lees. In both trials, fecal egg count (FEC) and live weight were measured weekly. PN lees displayed positive in-vitro anthelmintic activity. In Trial 1, lees provided insignificant (7%) increase in cumulative liveweight gain relative to Control (P >0.05). In Trial 2, the overall mean daily gain (g/day) was not different with lees feeding but slight increased (26.6%) following drenching with Matrix (P >0.05). Lees, at the concentration used in this trial of 460 mg tannin/day/animal, did not offer a reliable stand-alone anthelmintic control.

Efficiency, cheese yield and carbon emissions of Holstein-Friesian, Jersey and crossbred cows: an overview - Sneddon NW; Lopez-Villalobos N; Baudracco J (Proceedings of the New Zealand Society of Animal Production, 2011)
This paper provides an overview on differences between Holstein-Friesian (HF), Jersey (J) and crossbred cows, for feed conversion efficiency (FCE), dry matter intake (DMI), cheese yield and carbon emissions. It was found that J cows have significantly higher DMI per kilogram of live weight (LWT) compared to HF and F1 HFxJ cows (3.64, 3.81 and 3.23 g DMI/kg LWT, respectively). A higher DMI per kilogram of LWT can result in more energy available for milk production, assuming that the maintenance requirements per unit of LWT are equal between the breeds. Estimates of FCE measured as grams of milksolids (milkfat plus milk protein) per kilogram of DMI were higher in J than HF cows (112 vs 97 g MS/kg DMI) in the reviewed papers. For grazing cows, a higher proportion of feed consumed is converted into milk production than used to cover maintenance energy requirements in J cows. This may result in lower greenhouse gas emission intensity from J than HF cows. Opportunities for the utilisation of breed differences to increase FCE and reduce carbon footprint and increase overall farm profitability in grazing dairy systems requires further farming system research to elucidate the relative efficiencies of the most common dairy breeds.

Feeding behaviour differs between dairy calves selected for divergent feed conversion efficiency - Green TC; Waghorn GC; Beausoleil NJ; MacDonald KA (Proceedings of the New Zealand Society of Animal Production, 2011)
Feeding behaviour and efficiency of feed utilisation, measured as residual feed intake (RFI; defined as actual feed intake minus predicted feed required), were measured in dairy calves aged six to seven months-old, and associations between the two variables were determined. The intake, feeding behaviour, and live weight of 219 female Holstein-Friesian calves were recorded for 46 days. Animals were housed in an outdoor facility comprising 28 pens, each with a single-access feeder containing dried, cubed lucerne. Efficient animals were associated with lower intakes (r² = 0.29), fewer meals/day (r² = 0.05), less time spent eating/day (r² = 0.03), and slower eating rates (r² = 0.03). The 30 most efficient animals consumed less (mean ± standard error of difference; 6.15 vs 7.46 ± 0.20 kg cubes/day), had fewer meals (4.03 vs 4.85 ± 0.29 meals/day), and spent less time feeding (2.68 vs 2.93 ± 0.11 hours/day) compared to the 30 least efficient animals (all P <0.05). Rate of liveweight gain, eating rate, amount eaten per meal, and meal duration did not differ between the 30 most efficient and 30 least efficient animals (P >0.05). In conclusion, differences in feeding behaviour were found between dairy calves selected for divergence in efficiency which may have implications for their management.

Fenbendazole as a possible marker of supplement intake in sheep - Fishpool FJ; Kahn LP; Tucker DJ; Nolan JV; Leng RA (Proceedings of the New Zealand Society of Animal Production, 2011)
This study aimed to determine the dose-dependent relationship between oral doses of fenbendazole (FBZ) and the plasma concentration of its metabolites, oxfendazole (OFZ) and fenbendazole-sulphone (SUL). Twenty five, two year-old, Merino wethers were equally allocated to treatment groups of different oral dose rates of FBZ (n = 5) and housed in individual pens. Treatment groups were designed to provide daily oral doses of 0.25, 0.5, 1.0, 2.0 and 4.0 mg/kg live weight of FBZ, suspended in water, for six days. Blood samples were collected from each animal at 48, 96, and 144 hours after administration of FBZ. Plasma was equally combined within each animal and analysed to determine concentrations of FBZ, OFZ and SUL. There was a positive linear relationship between FBZ dose rate and FBZ metabolite plasma concentration (R2 = 0.991, P <0.001). Mean separation of plasma concentrations indicated significant differences (P <0.05) between treatments designed to provide 1.0, 2.0 or 4.0 mg/kg/day FBZ. Plasma concentrations of animals which received 0.25 or 0.50 mg/kg/day FBZ were significantly lower than other treatments (P <0.05). The results from this experiment provide preliminary support for the investigation of FBZ as a useful marker to estimate supplement intake of grazing animals.

Flexibility and climate risk management in high stocking rate dryland sheep farming systems - Bywater AC; Logan CM; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2011)
A trial unit of 87.8 ha with conventional grass-based pastures and one of 85.1 ha with high legume-content pastures were used to investigate the impact of climate-risk management strategies on production and profitability of dryland sheep farming systems. The target stocking rate of both units was 14 stock units (SU)/ha, which is markedly higher than the regional monitor farm at 8.8 SU/ha. Information on the feed supply and animal feed requirement of the two units for 2008/09 and 2009/10 are presented, along with differences in weather patterns, soils moisture, climate-risk responses used, and stock sales between the two years. Results from the grass-based unit indicated that the flexible livestock policies used and climate-risk management responses imposed were able to increase farm profitability and reduce its variability between years in comparison to the local Ministry of Agriculture and Forestry monitor farm model. However, the same was not true for the high legume-content unit, which encountered a number of problems with high lamb deaths and poor lamb finishing in 2008/09. Soil moisture level in the top 25 cm proved to be a simple, inexpensive and effective indicator for making appropriate farm management decisions in response to changes in the climate.

The future for animal welfare science: Is there a clear direction or are we just responding to issues? Introductory remarks. - Stewart M (Proceedings of the New Zealand Society of Animal Production, 2011)
Animal welfare has emerged as a major factor that must be considered in order to maintain access for New Zealand’s pastoral products into overseas markets. Increasing consumer interest and concern is placing pressure on our animal-based agricultural industries to provide "welfare friendly" products. Although, on the positive side, due to our pasture-based systems compared to indoor systems overseas, New Zealand is... Continued

Genetic analysis of incidence of recorded clinical lameness in New Zealand dairy cattle - Chawala AR; Lopez-Villalobos N; Margerison JK; Spelman RJ (Proceedings of the New Zealand Society of Animal Production, 2011)
Herd records from 76,357 cows, collected during the 2005/06 to 2008/09 milking seasons from 155 herds in the Livestock Improvement Corporation (LIC) young sire progeny test scheme, were used to estimate genetic parameters and breed effects for incidence of recorded clinical lameness (RCL) in Holstein-Friesian, Jersey and crossbred dairy cattle. RCL was coded "1" for cows that presented at least one event of RCL at any day during the season and "0" for cows without RCL. Genetic parameters were estimated with a repeatability animal model across breeds. The average incidence of RCL per herd was 6.3% and ranged from 2% to 34%. Jersey cows had significantly (P <0.05) lower incidence (6.0%) than Friesian cows (6.8%) but similar to crossbred cows (6.1%). The heritability estimate for incidence of RCL was 0.016 ± 0.003 (standard error) while the repeatability was 0.071 ± 0.005. Sire estimated breeding values for RCL ranged between -5 and 8% with Jersey sires showing the lowest values. These results suggest that selection for resistance to lameness will result in a low rate of genetic gain but using Jersey sires can be an alternative to increase genetic resistance to lameness in New Zealand dairy cattle.

Genetic and phenotypic relationships between flystrike indicator traits in a stud Merino flock - Scobie DR; Hickey SM; Maslen DP; Black GM (Proceedings of the New Zealand Society of Animal Production, 2011)
Increasing breech wrinkles, breech cover and dags increase flystrike susceptibility of Merino sheep. Urine stain has been implicated in flystrike, although there is a paucity of data. At tail docking in 2007, 2008 and 2009 on a property breeding Merino rams, breech wrinkle (1 to 5) was scored on 238, 202 and 337 lambs that were the progeny of 12, 9 and 9 sires respectively. Dag score (0 to 5), urine stain (0 to 5) and breech cover (1 to 5) were scored at 100 days of age. Breech wrinkle score (h² = 0.51 ± 0.11) and breech cover (h² = 0.27 ± 0.08) were heritable, and phenotypically (0.16 ± 0.04, P <0.05) and genetically correlated (0.77 ± 0.14, P <0.05). Dag and urine stain scores were skewed towards low scores and the heritability estimates for these traits were low (h² = 0.08 ± 0.07 and 0.04 ± 0.06 respectively). Yearling clean fleece weight was heritable (h² = 0.28 ± 0.13) and genetically correlated with breech cover (-0.62 ± 0.26, P <0.05). There was no evidence of flystrike during the investigation, but there was potential to decrease susceptibility by decreasing breech cover and breech wrinkles in this flock.

Heat stress in farm animals - Schütz KE (Proceedings of the New Zealand Society of Animal Production, 2011)
Heat stress affects production and welfare in farm animals. In warm weather animals will change their behaviour in order to cool down, for example by seeking shade or other cooler microclimates, and by altering activity patterns, body postures and feed intake. In addition to behavioural changes, physiological mechanisms will occur, such as increased respiration and body temperature. There is consistent evidence that the reduced productivity in association with heat stress can be alleviated by providing different types of cooling. However, more research is needed in order to explore how to best cool farm animals and appropriate cost benefit analyses of providing different types of cooling in New Zealand conditions needs to be carried out to improve profitability and welfare. Animals change their behaviour before changes in production can be detected, therefore animal behaviour can provide insight into when and how to cool animals.

The importance of sustainable food production for our markets - Brown M; Butler D (Proceedings of the New Zealand Society of Animal Production, 2011)
New Zealand market advantage is at the "top-end" of value, in the production of sustainable, superior quality, highly valued protein. Enhancing our image as the "garden of the pacific", will lead to greater opportunities for economic growth and a prosperous red meat industry, while at least maintaining, if not improving, our natural resources. This paper discusses what sustainable food production means and identifies some of the expectations of our international markets. The paper also briefly describes how Alliance Group Limited is responding to improving sustainable food production. Strategies outlined include improving farm practices, processing capabilities and improving quantity and quality of product.

In vitro digestion of ryegrasses harvested in the morning and afternoon to manipulate water soluble carbohydrate concentration - Burke D; Pacheco JL; Cosgrove GP (Proceedings of the New Zealand Society of Animal Production, 2011)
The concentration of water soluble carbohydrate (WSC) increases during the day and the difference between morning and afternoon is greater and more consistent than the difference between cultivars. An in vitro batch culture system was used to compare the fermentation of ryegrass cultivars that differed in WSC, after harvesting samples in the morning (08:00 h) and afternoon (16:00 h). Bottles were placed in a shaking incubator at 39°C and removed at 0, 2, 4, 6, 8, 12 and 24 hours to measure pH and concentrations of ammonia and volatile fatty acids (VFA). Ryegrasses harvested in the afternoon had 81-114 g/kg dry matter more WSC, 3-12 g/kg dry matter less neutral detergent fibre and 14-25 g/kg DM less crude protein than morning samples. Compared to morning harvested ryegrass cultivars, afternoon harvested ryegrass cultivars had the lowest yields of VFA. Afternoon-harvested ryegrass cultivars, especially high sugar ryegrass, were rapidly fermented and after four hours the pH of high sugar ryegrass decreased to less than 5.8, which has been reported to cause suboptimal fibre digestion. It may be possible to manipulate the WSC concentration of a pasture diet by altering grazing management practices. Further research is required to characterise the optimum concentration of WSC for efficient rumen fermentation.

The incidence of goitre in newborn lambs from ewes fed fodder radish, rape or Italian ryegrass with or without iodine supplementation - Judson HG; Barrell GK (Proceedings of the New Zealand Society of Animal Production, 2011)
Brassicas are an important forage species on many New Zealand sheep farms. However, glucosinolates present in some brassicas can cause iodine deficiency in lambs when pregnant ewes are fed such crops during gestation. To investigate the effect of differences in glucosinolate profile of fodder radish and a brassica on ewe thyroid function and incidence of goitre in lambs born to ewes grazing these crops during pregnancy, a 3 x 2 factorial study utilising three diets (Italian ryegrass, fodder radish, rape) and two rates of iodine (I) supplementation (with, without) was conducted. Thyroid hormone (T3, T4) response to a thyroid releasing factor (TRF) challenge in ewes and incidence of goitre in newborn lambs was determined. A mild goitre, based on thyroid weight:lamb weight ratio (g/kg) of >0.4, was recorded only in newborn lambs from ewes fed rape and the incidence was higher (75% vs 11%) in those without I supplementation. Pregnant ewes grazing radish or rape had the lowest T3 and T4 responses to TRF, except in the case of T4 where there had been I supplementation. Differences in glucosinolate content and composition may explain the differing results for sheep fed radish or rape.

Legend session: Forage secondary compounds; past, present and future - Barry TN (Proceedings of the New Zealand Society of Animal Production, 2011)
Forages contain plant secondary compounds. These are primarily produced to protect the plant from attack by micro-organism, insects and herbivores. Research during the last 40 years has produced an insight into the biochemistry, metabolism and interaction of these compounds, specifically the unique amino acid S-methyl cysteine sulphoxide (SMCO) and condensed tannins (CT). Both occur within forage consumed by farmed livestock. SCMO induces anaemia in herbivores. Through plant breeding and effective management brassica crops can now be fed to livestock as a supplement without restricting growth rate. A wide range of plants contain CT. CT have been shown to have the capacity to bind to soluble proteins in the rumen enabling increased absorption of essential amino acids from the small intestine. This benefits body growth, milk production, wool growth and ovulation rate. CT have also been shown to have a direct effect on gastrointestinal parasites inhibiting their growth and fecundity, particularly in sheep. As a result of this detailed research we are now able to exploit the unique attributes of some plant secondary compounds and use them to our advantage to benefit animal production and the performance of our farmed livestock. Ways in which we able to do this are discussed.

Life cycle assessment - a tool for evaluating resource and environmental efficiency of agricultural products and systems from pasture to plate - Ledgard SF; Lieffering M; Zonderland-thomassen MA; Boyes M (Proceedings of the New Zealand Society of Animal Production, 2011)
Life cycle assessment is a useful tool to evaluate the resource use and environmental efficiency of agricultural systems and products, and to account for these along the whole supply chain or life cycle. Its application to agricultural products is most evident with carbon footprinting, where it is being used at industry, policy and consumer levels including for eco-labelling. Research in dairy, sheep and beef systems has shown that the farm-related stage is the main contributor to product carbon footprints and that in New Zealand they have been gradually reducing over time with increasing productivity. While the carbon footprints of New Zealand pastoral agricultural products are generally low compared to overseas products, there can be up to a two-fold variation between individual farms, illustrating the potential for on-farm efficiency gains. Fossil fuel and total energy use on New Zealand farms are low compared to overseas but are increasing with greater use of high energy-demanding nitrogen fertiliser. Water footprinting is likely to become an important resource indicator with the global focus on fresh-water scarcity. A key benefit of life cycle assessment is that it enables evaluation of the potential impacts of products on multiple resource use and environmental indicators for system optimisation.

Methane output and rumen microbiota in dairy cows in response to long-term supplementation with linseed or rapeseed of grass silage- or pasture-based diets - Martin C; Pomiès D; Ferlay A; Rochette Y; Martin B; Chilliard Y; Morgavi DP; Doreau M (Proceedings of the New Zealand Society of Animal Production, 2011)
The long-term (>12 months) effect of fat supplementation on methane (CH4) output and rumen microbiota was measured in dairy cows. Twenty lactating dairy cows were fed indoor with grass silage/hay (Period 1), then outdoor with pasture-based diets (Period 2), and allocated to three dietary treatments for two consecutive entire lactations. Diets were not supplemented (C) or supplemented with 2-3% dry matter of extruded linseed (EL) or extruded rapeseed (ER). Individual intake, milk and CH4 production (sulphur hexafluoride tracer technique) were measured on five consecutive days in both periods. Rumen pH, volatile fatty acid (VFA) concentrations and microbial numbers were measured on rumen fluid samples collected before feeding. For both periods, CH4 yield (g/kg dry matter intake) was lower for EL (-15%; P <0.001), and numerically higher for ER (+14%) compared to C. The unexpected effect of ER on CH4 emissions remains difficult to explain. Measured as g/kg fat corrected milk, CH4 output remained lower for EL (-26%, P <0.05) than for C and ER, for both periods. Diet EL did not modify rumen VFA profiles and microbial numbers compared to C. Our work highlights the long term efficacy of EL supplementation of grass-based diets as a CH4 mitigation option.

Modelling farm management scenarios that illustrate opportunities farmers have to reduce greenhouse gas emissions while maintaining profitability - Dynes RA; Smeaton DC; Rhodes AP; Fraser TJ; Brown MA (Proceedings of the New Zealand Society of Animal Production, 2011)
Farmer focus groups have been involved in a range of learning exercises and farm system modelling exercises to determine the effect that alternative farm management scenarios would have on greenhouse gas (GHG) emission profiles on-farm. Annual GHG emissions from the current livestock farming policies for the sheep and beef property were estimated to be 4.91 tonnes of carbon dioxide equivalents per hectare (t CO2-e/ha) or 14.3 kg CO2-e per kg of meat and fibre produced. All of the alternative farm management options had a small impact on total GHG emissions, ranging from a reduction of 0.67 t CO2-e/ha to an increase in 0.42 t CO2-e/ha (-13% and + 8% of the whole farm emissions per hectare, respectively). Most exposed the business to greater risk due to market and climate variability. The Canterbury dairy farm annual GHG emissions from the current farm were estimated to be 13.1 t CO2-e/ha or 9.9 kg CO2-e per kg of milk solids. Across the mitigation scenarios investigated total GHG emissions were up to 14% lower than the baseline farm while emissions intensity ranged from 33% higher to 9% lower than the baseline farm. Opportunities which decreased emissions intensity and increased profit were identified; these require consideration of multiple risks around climate and market variability.

Painful husbandry procedures and methods of alleviation: a review - Sutherland MA (Proceedings of the New Zealand Society of Animal Production, 2011)
Painful husbandry procedures are routinely performed on farms in New Zealand for various reasons. Tail docking is routinely carried out on sheep to prevent flystrike and on pigs to prevent tail biting. In some countries this procedure is still performed on dairy cows to improve udder hygiene and worker comfort. Castration is commonly performed on lambs and calves to reduce aggressive and sexual behaviours, prevent unwanted breeding, and modify carcass characteristics. Dehorning is performed on cattle to reduce the risk of injury to stock people and other animals and antler removal in deer is carried out for commercial reasons. All of these procedures cause behavioural and physiological changes indicative of pain, but are commonly performed without pain relief on farms. This review will cover the rationale and the behavioural and physiological responses caused by these common husbandry procedures. Possible methods of pain relief or alternative strategies to these procedures will then be discussed as well as the implications for New Zealand and where future research needs to be focussed.

Pasture growth and quality, and lamb growth rates in high stocking rate dryland sheep farming systems - Bywater AC; Logan CM; Edwards GR; Sedcole JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Pasture growth and quality, and lamb growth rates were measured on a conventional grass based trial unit of 87.8 ha and a high legume unit of 85.1 ha, established to investigate climate-risk management strategies within high stocking rate dryland sheep farming systems. There was no difference between the units in total pasture production with a pasture utilization of 71.7% and 74.3% on the grass and legume units, respectively. Metabolisable energy values remained close to, or above, the target values throughout the growing season. Preweaning lamb growth rates averaged 304 g/day on both units. There were significant differences between singles (342 g/day), twins (300 g/day) and triplets (254 g/day) and between lambs from first cycle (294 g/day) and main mob ewes (315 g/day). There were some differences in lamb growth rates between different pastures types but these were not consistent between years. Post-weaning growth rates averaged 137 g/day with significant differences attributable to litter size, mob and year. Growth from birth to sale averaged 295 g/day, slightly less than the target of 300 g/day. Thus high lamb growth rates are possible on a range of pasture types on dryland at low pasture covers of high quality.

Physical and physiological factors associated with twin- and triplet-born lamb heat production at 24 to 36 hours of age - Kerslake JI; Kenyon PR; Morris ST; Stafford KJ; Morel PCH (Proceedings of the New Zealand Society of Animal Production, 2011)
This study attempted to identify physical and physiological factors of twin- and triplet born lambs within the first 24 to 36 hours of life which are associated with maximum heat production on a per lamb basis (W/lamb) and a per kg of birth weight basis (W/kg). Multiple regression analyses revealed that lamb birth weight accounted for 34 percent of the variation in maximum heat production on a per lamb basis (P <0.001), whereas, inclusion of plasma non-esterified fatty acids (NEFA; P <0.01), tri-iodothyronine (T3; P <0.05) and glucose concentrations at 24 to 36 hours of age (P <0.05) increased the accountability to 59 percent. Multiple regression analyses also revealed that plasma NEFA concentrations at 24 to 36 hours of age accounted for 15 percent of the variation in maximum heat production on a per kg of birth weight basis (P <0.01), whereas, inclusion of plasma T3 at 24 to 36 hours of age increased the accountability to 22 percent (P <0.05). Overall these results suggest that having greater lamb birth weights, plasma thyroid hormone, glucose and NEFA concentrations at 24 to 36 hours of age is beneficial for twin- and triplet-born lamb thermoregulation during periods of cold stress.

Predicting the benefits of two stage genomic selection in young breeding rams - Sise JA; Linscott EM; Amer PR (Proceedings of the New Zealand Society of Animal Production, 2011)
A two stage selection index model was developed to assess the cost effectiveness of using genomic technologies to assist in selection decisions for retention of ram lambs for breeding within a ram breeder flock. The principle of two stage selection is that many of the benefits of an expensive, but more accurate, measure of genetic merit can be captured while drastically reducing measurement costs. This paper describes the two stage model used, and some of the potential benefits of testing the top 6–50% of selection candidates ranked according to estimated breeding values, prior to ranking on a combined score using genomic breeding values. The model assumes a hypothetical panel of markers and trait predictive accuracies to explore the benefits of selection using both types of breeding values. The value of genetic progress is assessed using selection index theory to predict trait changes according to a selection index recently revised for implementation as the recommended index for dual purpose sheep in New Zealand. Results suggest that maximum benefits were obtained when the top 10-20% of selection candidates were tested, with the level of benefits dependent on both the prediction accuracy and price of the test.

Presidential Address 2010 - What will it take to feed the world and what is the role of New Zealand animal production in this? - Back PJ (Proceedings of the New Zealand Society of Animal Production, 2011)
A recent United Nation’s report stated that the world’s growing population will require twice as much food in 40 years time. What opportunities and challenges does this present for agricultural product producing countries? How will researchers meet the challenge of feeding a world population that is estimated to grow to 9 billion people by 2050? This is not an area that... Continued

Production variables influencing the auction sales price of New Zealand Thoroughbred yearlings - Waldron K; Rogers CW; Gee EK; Bolwell CF (Proceedings of the New Zealand Society of Animal Production, 2011)
Data were obtained from the New Zealand Thoroughbred studbook and the online sales results for the 2004 National Yearling Sales Series. Across the three sales categories, 477, 523, and 354 yearlings were offered at the Premier, Select and Festival sales, respectively. There were significant differences in the representation of yearlings across the three sales categories based on: sire service fee, vendor category, purchaser country of origin, and dam age. There were fewer fillies catalogued in the Festival sale compared to Select or Premier sales (P <0.05). Within the general linear model, auction price (log10) was significantly influenced by sales category: Premier ($71,285, 95% Confidence interval (CI), $61,801-$82,224), Select ($24,831, 95% CI, $22,233-$27,733) and Festival ($9,462, 95% CI, $8,072-$11,091, P <0.001). Sales price (log10) was also significantly influences by sire service fee, vendor category, purchaser country of origin, and mare age. Colts sold for more than fillies ($29,040, 95% CI, $26,668-$31,695 vs. $22,542, 95% CI, $20,370-$24,945, P <0.001) across all sales categories with an interaction of sales category and gender (P = 0.003). These results indicate that in order to optimize gross returns, vendors require colts that are marketed through the Premier sale, from older established broodmares, with a pedigree that appeals to Australian buyers.

Raising lambs with intact tails to meet retailer welfare requirements: on farm feasibility and farmer perspectives - Rogers AR; Dowling SK; Webster JR (Proceedings of the New Zealand Society of Animal Production, 2011)
The aim was to study the practical feasibility of raising lambs with intact tails to satisfy welfare concerns over tail-docking. On four farms, two groups of ewes were bred with either a farm ram (Normal) or a Dorper ram (Dorper). Lamb body weight and dag scores were monitored at weaning and before transport to slaughter. Tail length was measured at weaning. Dorper-sired lambs were not tail-docked. Farmers recorded all management procedures and participated in a post-trial questionnaire. On average, the number of handling and health treatments, farm labour and measurements at weaning and transport were similar for the Normal and Dorper-sired lambs. Dag scores averaged 1.2 and 1.3 at weaning, and 0.6 and 0.8 at transport for Normal and Dorper-sired lambs, respectively. Three farms returned a higher value/head for their Dorper-sired lambs. Three farmers stated they would not raise lambs with intact tails in the future unless they received a higher premium. One farmer reported that he would continue to raise undocked Dorper-sired lambs. These results suggest that while it is possible to meet retailer demands for higher welfare standards by raising lambs with intact tails, industry uptake may be dependent on higher premiums that satisfy the perceived extra costs of the farmers.

The role of breeding in reducing sheep GHG intensity - Ludemann CI; Byrne TJ; Sise JA; Amer PR (Proceedings of the New Zealand Society of Animal Production, 2011)
Historic and potential future greenhouse gas (GHG) emission reductions resulting from genetic selection decisions in sheep have been quantified. Historic genetic trends in number of lambs born in maternal breeds and growth in terminal sire breeds were estimated to have reduced GHG emissions per kilogram of lamb carcass weight by 0.45% and 0.09% per year of genetic change, respectively. The implications of future selection using different indexes were also examined. Selection based solely on farm profits could lead to emission reductions per unit of product by 0.185 kg CO2-e/kg carcass weight, or a 0.59% reduction in lamb carcass weight emissions per annum. Selection of sheep ignoring profit and solely targeting reduced GHG emissions per kilogram of lamb carcass weight could lead to emission reductions of 0.242 kg CO2-e/kg lamb carcass weight, equivalent to a 0.77% reduction in total emissions per annum. However, doing this would come at a cost of 26.6 cents per breeding ewe reduction of 23.7% per annum in annual genetic progress. An alternative index that provides a balance between reducing GHG emissions and improving farm profits was estimated to produce an annual 0.193 kg CO2-e/kg carcass weight or a reduction of 0.62% reduction in emissions per annum in GHG emissions with minimal sacrifice in genetic improvement of farm profitability.

The role of legislation in improving farm sustainability and how the New Zealand Government intends to incentivise the agricultural industry - van Reenen EH; Pickering AH (Proceedings of the New Zealand Society of Animal Production, 2011)
The New Zealand Government has put in place a number of mechanisms aimed at improving farm sustainability and incentivising action. In relation to climate change, the key mechanism is the New Zealand Emissions Trading Scheme (ETS), which has been designed to put the New Zealand economy on a path to lower greenhouse gas (GHG) emissions and to respond to the country’s international obligations. Although all developed countries that have ratified the Kyoto Protocol are responsible for their agricultural emissions, New Zealand is the only country in the world to include agriculture in an emissions trading scheme. With the inclusion of agriculture there are three key ways to incentivise a reduction in GHG emissions on-farm. These are through the point of obligation, the emission factor methodologies, and the allocation of "New Zealand Units" to the sector. Introducing agricultural GHG emissions into a New Zealand emissions trading scheme brings with it challenges and opportunities in a country that is heavily reliant on primary production for the health of the economy.

Is rumen retention time implicated in sheep differences in methane emission? - Pinares-Patiño CS; Ebrahimi SH; McEwan JC; Dodds KG; Clark H; Luo D (Proceedings of the New Zealand Society of Animal Production, 2011)
Breeding ruminants for low methane (CH4) emissions is an attractive mitigation approach for this greenhouse gas. During the last three years research has progressed at AgResearch to accurately identify individual sheep with contrasting low (Low) and high (High) methane yields. A study was conducted using these animal resources in order to explore the animal factors responsible for the observed differences between rankings. For this, the sheep were fed first on fresh pasture forage (pasture) and then on pellets containing lucerne hay and wheat grain (pellet). Methane emissions were measured in respiration chambers over two consecutive days. Feed dry matter digestibility (DMD) was estimated from a total faecal collection, whereas ruminal retention times of feed particles (PRRT) and solutes (SRRT) were estimated by single dosing of external markers. Methane yields from the High sheep were higher (P >0.05) than from their Low counterparts both the pasture and pellet diets. High emission ranking sheep had higher (P <0.05) DMD and SRRT than their Low counterparts, whereas PRRT was only numerically higher for the High sheep than for the Low sheep. Results of this study align with previous findings that retention time of digesta is implicated in animal differences in CH4 emission.

Ruminal fermentation characteristics from sheep offered a fresh grazing allocation of a ryegrass-based pasture either in the morning or in the afternoon - Vibart RE; Burke JL; Pacheco D (Proceedings of the New Zealand Society of Animal Production, 2011)
Eight rumen-fistulated wethers were used to examine the effects of PM (16:00 h) versus AM (08:00 h) allocation of spring herbage from pasture on aspects of ruminal metabolism that lead to increased utilisation of nutrients. The experimental period consisted of two phases; adaptation to diets and intensive sampling. During the adaptation phase, total volatile fatty acids (VFA) and ammonia concentrations were greater for the PM group, whereas the ratio of non-glucogenic to glucogenic VFA did not differ. These results suggest greater fermentation from forage that had similar concentrations of crude protein, neutral detergent fibre, and water soluble carbohydrates, but greater organic matter digestibility (84.1 vs. 82.3%). During the intensive sampling phase, the mean total VFA and ammonia concentrations did not differ among groups, but the 24-hour pattern varied considerably for all variables measured. Unseasonal weather conditions during the trial were associated with smaller differences in water soluble carbohydrate accumulation than expected. Based on our results, at least four hours of sunshine were needed to obtain diurnal differences greater than 20 g per kg herbage DM. The implication of these findings on the implementation of nutritional management strategies warrants further investigation.

Selection decisions in Thoroughbred broodmares - Rogers CW; Gee EK (Proceedings of the New Zealand Society of Animal Production, 2011)
Using retrospective racing and breeding records the hypothesis was tested that in the last two generations there has been a significant increase in the proportion of race tested fillies entering breeding. During the 1998/99 breeding season there were 146 sires at stud, 92 had a Low cost service fee (<$5,000), 28 had a Medium cost service fee ($5,001-$10,000), 9 had an Expensive cost service fee (>$10,000) and 17 were Shuttle stallions. Of the 6,768 mares covered 46% were covered by Low cost, 22% by Medium cost, 12% by Expensive cost and 19% by Shuttle stallions. Three stallions from each of these four service fee categories were randomly selected and the opportunity for the female progeny sired by these stallions to enter yearling sales, race and enter the broodmare herd were examined. Significantly more 1999 born female progeny by Expensive (37%) and Shuttle stallions (34%) were presented for sale than those by Medium (1%) and Low cost sires (0%), and were more likely to race (85% and 82%) than those by Medium or Low cost sires (64% and 50%). Female progeny born in 1999 by Expensive sires were more likely to enter breeding (80%) than those by Shuttle (49%), Medium (43%) or Low cost sires (25%). The proportion of broodmares with race records decreased with each retrospective generation.

Sub-clinical uterine infection is associated with altered amino acid concentrations of follicular fluid in early lactation dairy cows - Back PJ; Lopdell T; Berg MC; Green MP (Proceedings of the New Zealand Society of Animal Production, 2011)
The effect of sub-clinical endometritis (scEndo) in early lactation on follicular amino acid (AA) concentrations was determined. On D21 and D42 postpartum cows were classified as having scEndo or Clean based on uterine cytology; >18% polymorphonuclear (PMN) cells amongst uterine nucleated cells. On D21 and D42, 35% and 7% of cows respectively were classified as having scEndo, with a large proportion of scEndo cows having self-resolved the infection by D42. Follicular histidine (P = 0.04), as well as alanine, aspartate and serine concentrations (P <0.1) were higher in scEndo compared with Clean cows. The effect of change in uterine status from D21 to D42 resulted in increased (P <0.1) follicular glutamate, ornithine and valine concentrations in cows that resolved infection. Correlation coefficients were determined to test the relationship between plasma and follicular AA concentrations. A greater number of AA in Resolved cows showed no relationship between plasma and follicular concentrations compared to Clean cows. Thus, scEndo is associated with an increase in follicular histidine and an increase in the concentration of several AA when a uterine infection is resolved. This study demonstrates that scEndo may be responsible for long-term alterations in follicular AA concentrations that could potentially result in altered oocyte viability.

Temporary alterations to milking frequency, immediately post-calving, modified the expression of genes regulating milk synthesis and apoptosis in the bovine mammary gland - Grala TM; Phyn CVC; Kay JK; Rius AG; Littlejohn MD; Snell RG; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2011)
Temporary changes to milking frequency during early lactation can elicit lactation-long changes in milk production. This study tested whether altered milking frequency, immediately post-calving, would affect mammary gene expression during and/or following treatment. Multiparous, grazing dairy cows (n = 150) were allocated to one of five treatments post-calving: milking thrice-daily (3X) for three or six weeks, and twice-daily (2X) thereafter; milking once-daily (1X) for three or six weeks, and 2X thereafter; or milking 2X for the entire lactation. Mammary tissue was biopsied from 12 cows per treatment at three, six and nine weeks postcalving and expression of milk synthesis and apoptosis genes measured using quantitative PCR. The milk fat, lactose and protein genes were down-regulated (P <0.05) in cows milked 1X compared with cows milked 2X. At nine weeks post-calving, cows milked 1X for three weeks had reduced mRNA levels of milk synthesis genes compared with cows milked 1X for six weeks (P <0.05). The expression of apoptosis genes was up-regulated (P <0.05) in cows milked 1X relative to 2X, during and post-treatment. There were no gene expression changes during 3X milking compared with cows milked 2X. Changes in gene expression observed in cows temporarily milked 1X reflect physiological changes consistent with longer-term reductions in milksolids yield.

Is there an association between dam live weight and litter structure in a flock of grazing Perendale sheep? - Sumner RMW; Henderson HV; Sheppard AM (Proceedings of the New Zealand Society of Animal Production, 2011)
Observational data from a grazing Perendale flock collected between 1985 and 2002 were analysed to investigate whether there was any association between variation in pasture availability over the summer, as reflected in live weight at joining and/or liveweight change between weaning and the subsequent joining, in association with litters of different sizes and sex structure, and the sex ratio of lambs born during the following spring, under pastoral farming conditions. The flock was managed at Whatawhata Research Centre until 1997 and thereafter at Winchmore Research Station. Data for a total of 3,516 lambs were analysed. Between year variation and variation associated with all the assessed factors, was consistent with chance variation. The proportion of males born was not significantly different from 0.50. Ewe age was significant at Winchmore when adjusted for lambing year, and litter size in both the previous and current lambings and liveweight change of the dam between weaning and joining, with more males born to mature ewes. Three percent more male than female lambs died between birth and weaning at both locations. It is unlikely sheep farmers can consistently influence the sex ratio of their lamb crop through changes in their flock management procedures.

Is there any advantage of early weaning of twin lambs born to yearlings? - Mulvaney FJ; Morris ST; Kenyon PR; Morel PCH; West DM (Proceedings of the New Zealand Society of Animal Production, 2011)
The objective of the current study was to investigate the effect of weaning twin lambs born to yearlings at 9, 11 or 13 weeks of age on the live weight of the yearling and her lambs. The yearlings and the lambs were allocated to one of three weaning treatment groups (9-week versus 11-week versus 13-week) on Day 1. Each treatment group was balanced for yearling and lamb live weight. At Week 13, all lambs were removed from the remainder of the experiment but the yearlings were monitored for a further six weeks. The yearlings and lambs were offered ad-libitum levels of herbage throughout the experimental period and the pre- and post-grazing mass was monitored weekly. The yearlings and lambs were weighed on Days 1, 7, 14, 21 and 28 while yearlings were weighed again on Days 35, 42 and 70. Pre- and post-grazing mass was monitored weekly. Yearling live weight did not differ (P >0.05) between treatment groups on Days 1, 35 or 70. Lamb live weight did not differ (P >0.05) on Days 1, 14 or 28. These results indicate that there is no advantage of early weaning of twin lambs born to yearlings on the live weight of the yearling or her lambs.

An update on genetic parameters for facial eczema susceptibility in New Zealand dairy cattle - Cullen NG; Morris CA; Hickey SM; Henderson HV (Proceedings of the New Zealand Society of Animal Production, 2011)
Resistance/tolerance to facial eczema (FE) is a heritable trait in New Zealand dairy cattle, as measured by genetic variation in liver enzyme levels. AgResearch has been collecting data from herds clinically affected by FE, by blood-sampling all cows in these herds, as a low cost method of phenotyping large numbers of animals. Over the past seven autumns, 66 herds and 14,799 cows were sampled. Breeding values for FE resistance were calculated for 238 sires. One complicating factor was the level of FE-protection provided by zinc sulphate administered through the farm water supply. Variable levels of serum zinc in cows were found, due to factors including water intakes and weather conditions. In zinc-treated herds there were three classes of cows: those still affected by FE, and others seemingly FE-tolerant either through genetics or having enough circulating zinc to provide protection. The zinc status of each herd was recorded at the time of blood sampling after a clinical outbreak. Data were analysed within zinc-treated and not zinc-treated herds to provide genetic parameters for each. Heritabilities in herds according to zinc status were very similar, regardless of zinc status.

The welfare implications of dystocia in sheep and cattle - Stafford KJ (Proceedings of the New Zealand Society of Animal Production, 2011)
Painful husbandry procedures are routinely performed on farms in New Zealand for various reasons. Tail docking is routinely carried out on sheep to prevent flystrike and on pigs to prevent tail biting. In some countries this procedure is still performed on dairy cows to improve udder hygiene and worker comfort. Castration is commonly performed on lambs and calves to reduce aggressive and sexual behaviours, prevent unwanted breeding, and modify carcass characteristics. Dehorning is performed on cattle to reduce the risk of injury to stock people and other animals and antler removal in deer is carried out for commercial reasons. All of these procedures cause behavioural and physiological changes indicative of pain, but are commonly performed without pain relief on farms. This review will cover the rationale and the behavioural and physiological responses caused by these common husbandry procedures. Possible methods of pain relief or alternative strategies to these procedures will then be discussed as well as the implications for New Zealand and where future research needs to be focussed.

The welfare of extensively farmed livestock - Fisher MW (Proceedings of the New Zealand Society of Animal Production, 2011)
Extensive farming involves husbandry of animals over a large area, animal performance, health and welfare dependent on ecology and farm management. Specific features providing both challenges and opportunities for good animal welfare include climatic, environmental and nutritional variation and extremes; infrequent human contact; greater freedom for animals to make choices affecting their well-being; a greater degree of natural selection; and fitter animals better able to cope with their environments. Stockmanship, in addition to drawing on personal experience and traits, requires an understanding of the constraints and opportunities afforded by the climate, the terrain and the biota. Intensification practices acting to increase productivity and efficiency need to be able to retain and enhance animal resilience to environmental changes. Animal welfare regulatory, monitoring and assurance expectations may need to acknowledge these distinctive features.

Why is clover better than ryegrass? - Nicol AM; Edwards GR (Proceedings of the New Zealand Society of Animal Production, 2011)
This review quantitatively compares the nutritive value of ryegrass and clover. It confirms that the animal performance on clover is on average 40% higher than on ryegrass. It establishes that although the digestibility of clover is less affected by stage of vegetative growth than ryegrass, the digestibility and metabolisable content of the two species is little different when compared at a young vegetative stage. Although the crude protein content of clover is often higher than that of grass the ratio of metabolisable protein to metabolisable energy supply is similar from the two forages. Despite a similar metabolisable energy content, the utilisation of metabolosable energy for growth is higher for clover than ryegrass. This may be due to a greater proportion of energy digestion in the small intestine. Most of the elements of ingestive behaviour, bite size, biting rate and intake rate are greater for clover than ryegrass and consequently the total gazing time and thus cost of harvesting clover are lower. The review concludes by estimating the relative contribution of increased efficiency of utilisation, reduced costs of ingestion and increased intake to the higher animal performance from clover.

Application of genomic information in a dairy cattle breeding scheme - Spelman RJ; Arias J; Keehan M; Obolonkin V; Winkelman A; Johnson D; Harris BL (Proceedings of the New Zealand Society of Animal Production, 2010)
Marker assisted selection has been applied in dairy cattle breeding schemes over the last decade with minor to moderate improvements in genetic gain. In most cases, the cost effectiveness of marker assisted selection has been neutral, at best. The completion of the sequencing of the bovine genome in 2006 has generated a large number of single nucleotide polymorphisms that has allowed the application of genomic selection. In addition, the cost of genotyping single nucleotide polymorphisms is considerably lower than microsatellite genotyping. Livestock Improvement Corporation has undertaken extensive genotyping of the sires that have been progeny tested in the last 20 to 30 years. Analysis of these data by Livestock Improvement Corporation researchers has identified combinations of markers that were used to obtain genetic evaluation of bulls from their DNA. By utilising this genomic information, semen from two-year-old sires has been sold to New Zealand dairy farmers. Over the past two years, the genomically selected bulls have accounted for approximately 15 to 20% of the inseminations. It is expected that selection based on genomic information, termed genomic selection, will increase the rate of genetic gain in New Zealand by 30 to 50%.

Application of resource allocation optimisation to provide profitable options for dairy production systems - Anderson WJ; Ridler BJ (Proceedings of the New Zealand Society of Animal Production, 2010)
A linear program (LP) model analysed resource use on a 100 ha dairy farm. A single optimum-profit combination was established for resources which were either optimised or constrained. It was found that, with a fixed herd of 320 milking cows, when production increased from 305 kg milksolids per cow (kg MS/cow) to 415 kg MS/cow, cash profit increased by 65%. This required additional supplements. If, however, feed demand and supply were optimised at 415 kg MS/cow, the LP reduced milking cow number rather than buy in feed to meet the increased feed demand from higher production per cow. At all production levels chosen between 305 and 415 kgMS/cow, it was most economic to dry off and cull cows early in dry summers to optimise feed demand vs. feed grown; use nitrogen (N) fertiliser to avoid a feed deficit only when response rates of better than 10 kgDM to 1 kg N could be expected; not use N for growing supplements to harvest. Pasture cover, within defined constraint levels, provided a buffer for feed demand and supply fluctuations. The study highlights the importance of assessing production, income and cost in an integrated framework to identify the point at which individual resources become limiting.

Asssociation among hormones and metabolites during the transition period and early lactation milk production - Edwards P; Mandok K; Lee JM; Burke CR; Kolver ES; Roche JR (Proceedings of the New Zealand Society of Animal Production, 2010)
The transition period is loosely defined as the period from three weeks pre-calving to three weeks post calving, and is regarded as a very important determinant of a cow’s lactation performance. Data were collated from three experiments in which blood was sampled repeatedly pre- and post-calving and milk production was recorded post-calving. Data were pooled within treatment and associations between blood hormones and metabolites, and milk production determined using regression analysis. Milk and milk solids (MS) yield were positively associated (P <0.05) with pre-calving plasma leptin and glucose concentrations and milk yield was negatively associated (P <0.05) with pre-calving non-esterified fatty acid (NEFA) and β-hydroxy butyrate concentrations. Milk yield was negatively associated (P <0.05) with plasma growth hormone, aspartate aminotransferase, and glutamate dehydrogenase concentrations in the first days of lactation, and with insulin like growth factor and glucose concentrations during the first five weeks post-calving. In comparison, plasma NEFA and albumin (ALB) concentrations post-calving and the ratio of NEFA to ALB were all positively associated (P <0.05) with milk and MS yield during the first five weeks of lactation. Data are consistent with a positive effect of calving body condition on milk production and an increased milk production with increasing condition score loss post-calving.

Automatic reading of Kamars for heat detection in dairy herds - Hempstalk K; Harris BL; Lopdell TJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Most existing heat detection systems for dairy cattle are labour-intensive requiring manual inspection of every animal to maximise submission rates. Our solution is to automate heat detection using Kamar HeatMount Detectors and a camera-based recognition system. The goal of our system is to obtain 99% sensitivity and specificity, ensuring that cows that are on heat are rarely missed and over-drafts are kept to a minimum. Trials of various camera prototypes have been undertaken over the past three years, most recently during the artificial breeding period in the Spring of 2009. Over 70,000 images from four farms were taken during the latest trials; these photographs were used to assess the system. When considering photo observations, the fully automated system had an error rate less than 1% across all sites in the latest trial, and reaches our goal of 99% sensitivity and specificity.

Blood metabolic profiles in Uruguayan Holstein and Uruguan Holstein x New Zealand Holstein-Friesian dairy cows - Periera I; Laborde D; Lopez-Villalobos N; Ruprechter G; Carriquiry M; Meikle A (Proceedings of the New Zealand Society of Animal Production, 2010)
Blood metabolic profiles were determined from 40 days prepartum to 60 days postpartum in Uruguayan Holstein (UH) (n = 13) and UH x New Zealand Holstein-Friesian first cross (UH-NZHF) (n = 13) cows with seven in each group experiencing their second lactation (L2) and six experiencing their third lactation (L3). Non-esterified fatty acids increased around calving and tended to be greater in UH-L3 cows as well as betahydroxybutyrate concentrations for 20 days after calving, consistent with the greater body condition score losses in this group. The UH cows had greater prepartum total protein concentrations than UH-NZHF cows. Concentrations decreased around calving and increased immediately thereafter. In UH-NZHF-L2 cows, total protein levels were consistently low throughout lactation. UH-NZHF L3 cows had greater albumin concentrations than UH L3 cows. Insulin concentrations were not affected by strain or lactation number and were diminished around calving. A similar pattern was found for IGF-1, although an interaction between strain and days-in-milk was found. Compared to UH cows, UH-NZHF cows had greater levels of IGF-1 at 35 days prepartum but lower levels of IGF-1 at calving. These data suggest that UH cows, especially L3 cows, had a more pronounced negative energy balance than UH-NZHF cows that may reflect a different pattern of nutrient partitioning possibly related to different pregnancy rates.

Can ultrasound eye muscle area scanning be used in the New Zealand deer industry? - Ward JF; Archer JA; Farmer RJ; Sweetman MF; Nicoll GB; JV Yuan (Proceedings of the New Zealand Society of Animal Production, 2010)
The New Zealand Deer Industry Productivity Strategy 2009-2014 (Deer Industry New Zealand, 2009) aims to increase deercarcass weight by 10% and introduce a carcass yield module to their performance recording database DEERSelect. In other livestock species real-time ultrasonography offers a non-invasive, non-destructive, standardised muscle measurement on live breeding stock (Faulkner et al.,1990). Ultrasound scanning allows eye muscle (M. longissimus dorsi)dimensions and cross-sectional area to be recorded as traits for genetic evaluation in the Sheep (SIL) and Beef (BREEDPLAN) performance recording databases.

Carcass linear measurements as predictors of meat yield in lambs determined by VIAscan - Bain WE; McEwan JC; McLean NJ; PL Johnson (Proceedings of the New Zealand Society of Animal Production, 2010)
Lambs yielding proportionally more lean meat are desirable to processing companies as they have a greater quantity of saleable product which also meets market demand withoutthe need for further processing. The quest for higher yielding lean lambs has seen a change in the lamb carcass grading system from classification on carcass weight and the GR measurement (total tissue depth above the 12th rib, 110 mm from the midline) (Kirton, 1989) to using imaging systems such as VIAscan®. VIAscan® is a two dimensional imaging system that estimates lean content of the carcass (Hopkins et al., 2004).

Cathelicidin levels in milk from cows infected with a range of mastitis causing pathogens - Pryor SM; Smolenski GA; Wieleczko RJ; Broadhurst; Stelwagen K; Wheeler TT; Haigh BJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Mastitis is an inflammatory condition of the udder that is highly prevalent in cows on New Zealand dairy farms. It results in reduced production, increased treatment costs and lower profitability (Petrovski et al.,2006). An elevated somatic cell count (SCC) in the milk, mainly due to recruitment of immune cells to the site of infection, is the most widely accepted standard for diagnosis of subclinical infection whereas bacteriological culturing is typically used for identification of the causative pathogen from clinical cases (Moyes et al.,2009; Schukken et al.,2003). At present, both tests require laboratory analysis and are not routinely performed on individual cows throughout lactation.

Circulating levels of C-type natriuretic petide (CNP) are strongly linked to pregnancy but not to liveweight change in ruminants - McNeill BA; Prickett TCR; Wellby M; Ridgway MJ; Espiner EA; Barrell GK (Proceedings of the New Zealand Society of Animal Production, 2010)
Marked increases in plasma C-type natriuretic peptide (CNP) during ovine pregnancy, and decline during periods of imposed caloric restriction, raise the possibility that CNP concentrations in ruminants are associated with changes in live weight (LWT) and metabolic demands. Accordingly we measured plasma concentrations of CNP and a related amino-terminal fragment of proCNP (NTproCNP) at weekly intervals in pregnant (n = 8) and non-pregnant red deer hinds (n = 4) and non-pregnant ewes (n = 8) run concurrently. Plasma CNP forms increased markedly during cervine pregnancy to achieve peak concentrations (NTproCNP 132 ± 9.5 pmol/L, CNP 2.14 ± 0.2 pmol/L) at 38 and 10 days pre-partum respectively, falling in the final week of gestation to reach pre-pregnancy levels immediately post-partum (P >0.05). There was no association between the concentration of CNP forms and change in LWT in either group of non-pregnant ruminants. We conclude that maternal concentrations of CNP forms are markedly raised in pregnant deer exhibiting similar changes to those found previously in pregnant ewes, and that the observed changes in plasma levels are likely to be independent of change in LWT. Maternal plasma concentration of CNP forms may be a useful marker of fetal well-being and maturation in ruminant livestock.

Comparison of breeding values between sheep ranked for resilience and resistance - de Lautour MB; de Lautour HB (Proceedings of the New Zealand Society of Animal Production, 2010)
The sheep industry has put considerable resources into studying selection for resistance by measuring faecal egg count (FEC). Resistance can also have reduced pasture larval challenge as an important spin off. Fewer resources have been put into selecting for increased resilience, animals which are able to grow under challenge, possibly because methods of selecting resilient animals are more labour intensive and difficult to standardise. Te Whangai, which has a flock of 9,000 ewes, 2,500 of which are recorded ewes for breeding industry rams, has been working with AgResearch monitoring resilience and resistance in their flock since 2001. An analysis using data from ram lambs born in 2007 and 2008 found the top ranked animals on resilience had higher than average breeding values for growth and wool weights, whereas the top ranked animals for resistance with a low FEC, had lower than average breeding values for growth and wool weights. In 2007, the average breeding value for eight month live weight for the top 60 resilient lambs was 6.55 kg greater than that for the top 60 resistant rams. These findings suggest caution is advised in selecting animals on FEC. Resilience is likely to be a better alternative.

Composition and in sacco degradation characteristics of winter growth of Lolium perenne, Lolium multiflorum and Lolium perenne x multiflorum ryegrasses - Sun XZ; Waghorn GC; Clark H (Proceedings of the New Zealand Society of Animal Production, 2010)
Nine ryegrass cultivars (3 perennial, 3 hybrid, 3 Italian types) were sampled during the winter of 2007 to measure chemical composition, degradation parameters and leaf morphology and to define differences that may be applicable to winter growth in dairy pastures. The grasses were harvested after seven and nine weeks of regrowth on June 18 and August 2. There were no differences between ryegrass types in the concentration (g/kg dry matter (DM)) of crude protein (227) but neutral detergent fibre was higher in perennial (468) than hybrid (435) or Italian (414) ryegrass types. Leaves were largest and widest for the Italian type, and shortest and narrowest for the perennials (P <0.001). Italian ryegrasses had the highest concentration of soluble DM. There were differences in the degradation rate (h-1) of insoluble DM; Italian (0.20), hybrid (0.18) and perennial (0.13) ryegrasses (P = 0.06). Ryegrass sampled after 9 weeks of regrowth, had a lower crude protein concentration than the earlier sampling (208 vs. 246) and a lower neutral detergent fibre concentration (392 vs. 486) but leaf characteristics, proportion of DM in the soluble fraction, and DM degradation rates were similar (P >0.05). The identification of differences in composition and degradation will assist with planning grazing management over winter.

Condensed tannins for priming innate immunity - Schreurs NM; Pernthaner A; Hein WR; Barry TN (Proceedings of the New Zealand Society of Animal Production, 2010)
The immune system of sheep, cattle and other ruminants contains unusually large numbers of gamma-delta () T lymphocytes. In lambs and calves, these cells may comprise more than 50% of the T cells circulating in blood while in rodents and primates, they typically account for less than 5% of blood-borne T cells. The T cells localise within mucosal surfaces of all species, particularly in the gastrointestinal tract. Compared to their rodent and human counterparts, ruminant T cells have a greatly expanded repertoire of antigen receptors (Hein & Dudler, 1993, 1997). They also express unique accessory molecules in their cell membrane which may reflect a differential capacity of the ruminant T cells to contribute to immune defence (Hein & Mackay, 1991).

Correlated responses following genetic selection to change age at puberty in Angus cattle - Morris CA; Amyes NC (Proceedings of the New Zealand Society of Animal Production, 2010)
Direct and correlated responses in a 23-year selection experiment to change puberty in heifers are reviewed. Selection was for age at first oestrus (AFO). It was applied in both sexes, using the genetic correlation (-0.25 ± 0.09) between scrotal circumference in juvenile males and AFO in female relatives. The main breeding lines were those selected for early AFO (AGE-), late AFO (AGE+), or unselected (Control). A 69-day difference (19% of the herd mean) was achieved between the two AGE lines, with a 3.0 cm (9.9%) difference in scrotal circumference. Relative to the AGE+ line, the AGE- line means were +10.8 ± 3.1 kg (3.9%) in yearling weight, -6.0 ± 3.0 kg (1.3%) in cow mature weight, -47 ± 6 kg (16%) in heifer weight at first oestrus, and +3.7 ± 1.5 percentage points for mixed-aged cow pregnancy rate. There were significantly fewer sub-fertile yearling bulls in the AGE- line (P <0.001), and maternal effects on autumn and winter weights on calves of this line were positive. For carcass composition, only depot fat differed significantly between lines (AGE- mean < AGE+ mean). No major unfavourable traits were observed in the AGE- line in this study.

Correlated responses following genetic selection to change faecal egg count in Romney - Morris CA; Wheeler M; Shaw RJ (Proceedings of the New Zealand Society of Animal Production, 2010)
Genetic studies of nematode parasite-related traits were carried out in New Zealand Romney sheep between 1979 and 2006. Breeding lines were selected for high or low faecal worm egg count (FEC), and managed alongside a control unselected line. FEC data were collected from lambs post-weaning, whilst exposed to continuous, natural, mixed-species, nematode parasite challenge under grazing conditions. Overall there were 33,314 records of lamb FEC, taken at ‘FEC1’ and ‘FEC2’ (first and second post-weaning sampling times, separated by a drench treatment). Genetic parameter estimates are reviewed, including correlations of FEC with lamb, anti-parasite antibody and ewe performance traits. The heritability of FEC in lambs was 0.26 ± 0.01 overall, with a repeatability of 0.40 ± 0.01. The genetic correlation between FEC1 and FEC2 was 0.85 ± 0.02. Trends were for low FEC to be associated genetically with slight reductions in post-weaning growth, and in ewe and lamb fleece weights, minimal change in autumn and yearling live weights, and increased weaning weight, dag score and anti-parasite antibody levels. In practice, ram breeders would normally use index selection procedures, to achieve higher production at the same time as a lower FEC, although a slower rate of change in FEC would be expected.

Crossing Angus cattle with Limousin as a method of increasing meat yield - Cullen NG; Morris CA; Taukiri KR; Hill SW (Proceedings of the New Zealand Society of Animal Production, 2010)
The myostatin mutation in Limousin cattle affects both dressing percent and meat yield, without a negative impact on calving difficulty. A trial was designed to introgress this mutation into Angus cattle, using double-copy Limousin bulls to produce F1 Limousin x Angus. Crossing the F1 individuals would produce F2 individuals with a quarter carrying two copies of the mutation. A pure-bred Angus herd was maintained as a Control, for breed and genotype comparisons. A total of 269 F1, 34 F2 and 129 Angus calves were born in the first four years of this trial, before a lack of funding led to early closure. A total of 112 surplus bulls were slaughtered, and measurements taken over three years, including a “butchers’ dissection” into saleable meat, fat and bone of one hind-quarter per animal. Limousin crosses were 9% heavier as yearlings, 7% heavier at slaughter and had 2.3% higher dressing percent (55.3% vs. 53.0%) than Angus. Hindquarters from Limousin crosses were 14% heavier than from Angus, and their meat yields were greater by 1.8% (77.0% vs.75.2%), due mainly to breed differences in bone weight. Overall, the Limousin-cross advantage was 6.5 kg (17%) of saleable meat per hind-quarter, with most of the extra meat in high-value cuts.

Daily water intake by individual cows on a pasture diet during mid lactation - Morris CA; Hickey SM; Thom ER; Waugh CD (Proceedings of the New Zealand Society of Animal Production, 2010)
Three small studies were undertaken in the Waikato involving daily measurements of water intake of individual mixed-age Holstein-Friesian and crossbred cows, mid lactation. In Trial 1 at Ruakura, cows were monitored whilst grazing and, in Trials 2 and 3 at DairyNZ, pasture was cut and fed to cows indoors. Mean daily water intakes by Trial were 41.3, 78.2 and 60.1 L/cow, respectively; standard deviations were 4.5, 8.3 and 7.2 L/cow, and between-cow repeatabilities averaged 0.56 ± 0.08. There were two days of rain in Trial 1; the greater of these rainfalls (26.4 mm) led to a 62% reduction in water intake. There was no rainfall above 2 mm in Trials 2 or 3. Daily feed intakes (and feed dry-matter percentages) of cows were also available (Trials 2 and 3), and combined daily water intake (calculated from actual-water intakes plus water content of the feed consumed) averaged 104.5 and 110.6 L/cow, respectively. At an average water intake from the trough of 60 L/cow, the 25% of cows drinking least are expected to drink ~8.4 L (14%) less than average. This knowledge is useful when planning management practices such as supplementing water with zinc sulphate for facial eczema protection.

Deer Improvement’s breeding scheme for venison production in red deer (Cervus elaphus) - Quinn-Walsh EG; Johnson DL; Chardon J; Spelman RJ (Proceedings of the New Zealand Society of Animal Production, 2010)
This paper describes the progress of the Deer Improvement breeding scheme that has been in place since 2004. The aim of the programme is to improve venison production through genetic selection for growth rate of lean meat with improved fertility, temperament and mature hind weight. The breeding programme currently comprises 500 hinds bred from stags selected for high growth rate with the intention of increasing hind numbers to over 1,000. This projected increase will be facilitated by the use of embryo transfer to multiply the genes of the top ranked yearling animals, thus shortening the generation interval. As part of the programme, all progeny are DNA parentage tested, weighed frequently during their first 12 months of life and temperament scored. Pregnancy and weaning rates are recorded in the nucleus and progeny testing herds. As a result of selection during the past six years, the average yearling weight has increased by 1.5 kg/yr over all farms involved in the breeding programme. In 2009, male fawns from the nucleus herd reached an average of 100 kg at seven months of age. This is greater than the current industry average of 75 to 78 kg for the same age.

Determining taste panel traits which contribute to the overall liking of New Zealand lamb as assessed by a British sensory panel - McLean NJ; PL Johnson; Charteris A (Proceedings of the New Zealand Society of Animal Production, 2010)
New Zealand is the world’s largest exporter of sheep meat with the United Kingdom being the single largest market (Meat & Wool New Zealand, 2009). Hence, the acceptance of sheep meat in international markets is an important economic issue (Prescott et al.2001). For retail purchasers of meat in the United Kingdom the visual appearance, the eating experience, and their interaction will influence how much the consumer is willing to pay for the product (Savellet al., 1989). To ensure repeat purchases of high quality New Zealand lamb by United Kingdom consumers, it is important that the consumer enjoys the overall eating experience of the product.

Differences in follicle dynamics and the importance of luteal support in young and old cohorts of genetically identical dairy cows - Green MP; Back PJ; Berg MC (Proceedings of the New Zealand Society of Animal Production, 2010)
There has been a documented decrease in fertility in the modern dairy cow selected for milk yield (Pryce et al.,2004). This emphasises the need for farmers in a seasonal grass-based system such as that in New Zealand to correctly manage herd genetics in conjunction with nutrition to optimise cow reproductive performance. The question remains however as to the relative influence and interdependence of these two factors in establishing a pregnancy, as an optimal size for the ovulatory follicle is directly related to successful conception and pregnancy (Perry et al., 2005).

Do fetuses from primiparous one-year-old ewes differ from those of multiparous mature ewes? - Loureiro MFP; Pain SJ; Kenyon PR; Blair HT (Proceedings of the New Zealand Society of Animal Production, 2010)
The number of ewe-lambs (8 to 9 months of age) mated in New Zealand has increased to approximately 33% over the last 15 years (Anon, 2009). There are many potential advantages to ewelamb breeding including higher net profits, more lambs produced per ewe productive lifetime, better use of spring herbage, increased efficiency, early recognition of fertility potential and increased rates of genetic gain (Hight, 1982). However, little is known about the long term impacts of selecting progeny born to these young ewes as replacement animals. There is some evidence from human studies to suggest that there may be negative impacts for both the offspring and to the first parity young mother (Lucas et al., 1999).