@article {3672, title = {Effects of a daily dose of zeolite on rumen ammonia of lactating dairy cows consuming fresh-cut ryegrass pasture}, journal = {New Zealand Journal of Animal Science and Production}, volume = {78}, year = {2018}, month = {07/2018}, pages = {137-141}, address = {Lincoln}, abstract = {Zeolites are aluminosilicates that can be safely fed to ruminants on a daily basis. They have a strong affinity for cations, including ammonium (NH4 +), which creates the potential to adsorb excess ammonium released in the rumen and reduce urinary nitrogen (N) excreted. The main objective of this proof-of-concept study was to evaluate the effect of a single dose of 300 g of zeolite, deposited into the rumens of cannulated dairy cows before the main morning meal of fresh-cut ryegrass pasture, on changes in rumen ammonium concentrations over the following 8 h. The two-week trial was a cross-over design with 12 cows, either fed ryegrass as a sole diet (Control) or with zeolite (Zeolite). There was a consistent trend for rumen ammonium concentrations in the zeolitetreated cows to increase more slowly over time, and were lower than control cows 8 h after the zeolite was given (P = 0.08). This study provides some indications that a daily dose of zeolite, fed at the onset of the morning meal, may have a moderating effect on rumen ammonium concentration, and reduce plasma urea N concentrations in lactating dairy cows fed a ryegrass-dominant diet.}, issn = {1176-5283}, author = {Beukes PC and Gregorini P and Waghorn GC and Selbie PB} } @conference {75884, title = {Are high breeding worth index cows more feed conversion efficient and nitrogen use efficient?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {109-113}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {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.}, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Bryant MA and Mandok K} } @conference {75895, title = {Can livestock production be increased without increasing greenhouse gas emissions?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {156-162}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {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.}, issn = {1176-5283}, author = {Waghorn GC} } @conference {75928, title = {Effect of condensed tannins from Pinus radiata bark on Trichostrongylus colubriformis larvae and adult worms in sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {304-308}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {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 {\textmu}g 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.}, issn = {1176-5283}, author = {Chan J and Waghorn GC and Molan AL and Brookes IM} } @conference {75923, title = {Feeding behaviour differs between dairy calves selected for divergent feed conversion efficiency}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {71}, year = {2011}, month = {Jan}, pages = {281-285}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Invercargill}, abstract = {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 (r{\texttwosuperior} = 0.29), fewer meals/day (r{\texttwosuperior} = 0.05), less time spent eating/day (r{\texttwosuperior} = 0.03), and slower eating rates (r{\texttwosuperior} = 0.03). The 30 most efficient animals consumed less (mean {\textpm} standard error of difference; 6.15 vs 7.46 {\textpm} 0.20 kg cubes/day), had fewer meals (4.03 vs 4.85 {\textpm} 0.29 meals/day), and spent less time feeding (2.68 vs 2.93 {\textpm} 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.}, issn = {1176-5283}, author = {Green TC and Waghorn GC and Beausoleil NJ and MacDonald KA} } @conference {69506, title = {Composition and in sacco degradation characteristics of winter growth of Lolium perenne, Lolium multiflorum and Lolium perenne x multiflorum ryegrasses}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {206-212}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {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.}, issn = {1176-5283}, author = {Sun XZ and Waghorn GC and Clark H} } @conference {69474, title = {Evaluation of sensors for monitoring rumen pH, temperature and pressure}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {71-76}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Electronic intra-ruminal sensors and telemetry offer new opportunities for remote monitoring of the rumen environment. Sensors capable of measuring pH, temperature and pressure were subjected to laboratory and intra-ruminal evaluation in rumen-fistulated cows offered baleage indoors or hay with pasture outdoors. Each bolus underwent a testing sequence consisting of i) bench-top calibration against certified devices, ii) testing in the rumen to validate sensor measurement against actual measurement, and iii) monitoring the rumen environment of cows under contrasting feeding conditions for periods up to 72 hours. Bolus efficacy was evaluated from the accuracy of temperature and pressure measurements, stability of pH measurements over several days and the data capture rate being the actual number of data transmissions received as a proportion of the number expected based on transmission frequency setting. Intra-ruminal records show clear relationships of pH with diet and feeding bouts, whilst temperature records indicated drinking. Pressure changes were more difficult to interpret but may indicate satiety. These devices provide non-disruptive monitoring of rumen parameters and would be useful for studies of nutritional manipulation and rumen digestion efficiency, and for monitoring aspects of animal health.}, issn = {1176-5283}, author = {Lin X and Pacheco D and Kemp PD and Waghorn GC and Cosgrove GP} } @conference {69470, title = {Ryegrass to lucerne-effects of dietary change on intake,milk yield and rumen microflora bacteria of dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {57-61}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {The value of legumes for milk production has been attributed to higher intakes by cows and a higher nutritive value compared to ryegrass. However, abrupt changes in diet can adversely affect production, even when the change is to feed with a higher feeding value. A 13-day indoor experiment compared the responses of 12 cows that were changed from ryegrass to lucerne (Medicago sativa L.) (L) on Day 4, with 12 cows remaining on ryegrass (R). Immediately after the change to lucerne there was a 24\% decrease in milk yield; this was temporary, as from four days after the change these cows averaged 20\% more milk than those fed ryegrass (L = 15.7, R = 13.1 kg milk/cow/d; P <0.001). The temporary decrease in milk yield was not due to decreased intake as lucerne-fed cows had higher intakes (L = 16.5, R = 14.8 kg dry matter/cow/d; P <0.001). Only small differences in the rumen microbial populations were apparent on the day diets changed. The temporary decrease in milk yield was more likely associated with a change in metabolism of the resident bacteria. Improved understanding of the microbial consequences of an abrupt dietary change will enable better management decisions to be made on-farm.}, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Attwood GC and Li D} } @conference {69515, title = {Variation in feed conversion efficiency in Holstein-Friesian heifer calves}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {70}, year = {2010}, month = {Jun}, pages = {250-252}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Feed conversion efficiency (FCE) is a measure of an animal{\textquoteright}s ability to convert feed into product and is a major determinant of profitability in livestock production. This study evaluated two determinants of FCE in Holstein-Friesian heifer calves, growth rate and residual feed intake (RFI). The improvement in FCE, measured as feed intake per unit of liveweight gain (kg/kg), associated with increased growth rate is well known (see Archer et al., 1999). It is measured when the energy costs of maintenance are relatively small compared to the energy intake that is partitioned into growth of animal tissues or lactation.}, issn = {1176-5283}, author = {Carnie KR and Davis SR and MacDonald KA and Waghorn GC and Obolonkin VV and Spelman RL} } @conference {60972, title = {Feeding birdsfoot trefoil (Lotus corniculatus) reduces the environmental impacts of dairy farming}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {179-183}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {An indoor feeding experiment using 16 late lactation Friesian dairy cows measured effects of increased proportions of birdsfoot trefoil (Lotus corniculatus; Lotus) in the diet on the partitioning of nitrogen (N) between milk, faeces and urine. Cows were housed in metabolism stalls for 12 days and fed diets containing 0\%, 15\%, 29\% or 45\% Lotus (\% Lotus dry matter (DM) per DM intake (DMI)) with the remainder perennial ryegrass pasture. Increasing the proportion of Lotus in the diet did not affect DMI but increased milk (P <0.001) and milksolids yields (P <0.01). The percentage of N intake partitioned to milk increased from 16\% (0\% Lotus) to 21\% (45\% Lotus) (P <0.01) with an increasing proportion of Lotus in the diet. The percentage of N intake excreted as faecal N also increased from 29\% (0\% Lotus) to 38\% (45\% Lotus) (P <0.001) while the percentage excreted as urinary N was reduced from 49\% (0\% Lotus) to 34\% (45\% Lotus) (P <0.01). Partitioning of N towards faeces has a favourable environmental impact since faecal N is largely retained in soils whereas urinary N is subject to volatilisation as ammonia, losses as nitrous oxides (a greenhouse gas) and leaching into groundwater. }, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Watkins KA and Bryant MA} } @conference {60971, title = {The variation in methane emissions from sheep and cattle is not explained by the chemical composition of ryegrass}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {69}, year = {2009}, month = {Jun}, pages = {174-178}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {A data base of over 3,000 ruminant methane emission records from individual animals used to compile New Zealand{\textquoteright}s greenhouse gas inventory, shows substantial variation in CH4 yields (g/kg dry matter intake (DMI)) within and between forage types. Multiple regression analyses were undertaken using datasets from sheep and cattle fed fresh ryegrass to determine the extent to which variation in CH4 yields could be explained by ryegrass chemical composition. Methane was measured using the SF6 marker dilution technique with sheep and cattle, and also directly by respiration calorimetry from sheep. Data from sheep showed a similar average CH4 yield from both techniques, but there was more variation in SF6 data (23.4 {\textpm} 5.73) than from calorimetry (23.1 {\textpm} 2.89). Cattle CH4 yields averaged 19.1 {\textpm} 3.70 g/kg DMI. Multiple regression analysis of sheep data showed pasture chemical composition accounted for <2\% of the variation determined by SF6 and 20\% of the variation from calorimetry. Only 13\% of the variation in yield from cattle was explained by ryegrass composition, so the majority of variance (>80\%) was not explained. We suggest the variation in CH4 emissions is affected by digestive characteristics of individual animals, and interactions with forage physical and chemical components. }, issn = {1176-5283}, author = {Hammond KJ and Muetzel S and Waghorn GC and Pinares-Patino CS and Burke JL and Hoskin SO} } @conference {41780, title = {A versatile sheep respiration chamber system for measurement of methane emission}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {68}, year = {2008}, month = {Jan}, pages = {29-30}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Brisbane, Australia}, abstract = {Globally, the single most important source of greenhouse gas emissions from grazing systems is enteric methane (CH4) arising as a by-product of the fermentation of feed in the reticulo-rumen of ruminants (Clark et al., 2005). Methane is implicated in global warming and in countries where livestock constitutes a major emission source such as New Zealand, international commitments are driving research to develop emission reduction technologies, for which accurate measurements of CH4 emissions are ...Continued }, issn = {1176-5283}, author = {Pinares-Patino CS and Lovejoy P and Hunt C and Martin R and Molano G and Waghorn GC and Clark H} } @conference {41739, title = {Monensin controlled release capsules for improved production and mitigating methane in dairy cows fed pasture}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {67}, year = {2007}, month = {Jan}, pages = {266-271}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Wanaka}, abstract = {Mitigation of ruminant methane is an important component of New Zealand{\textquoteright}s strategy to lower greenhouse gas emissions. Methods for mitigation must be profitable, easily achievable for producers and be applicable to a wide range of farming systems and topography. The rumen ionophore monensin, is potentially capable of meeting these requirements, but its effects on both production and methanogenesis have been variable with forage diets.A trial was undertaken with 60 lactating Friesian/Holstein dairy cows in early {\textendash} mid lactation and fed pasture over a 3 month period, to measure effects of a commercially available monensin controlled release capsule (CRC) on milk production, rumen metabolites and methane production. Monensin had no effect on fat or protein yield and therefore milksolids yield, 1.68 kg/day for both groups of cows, was unaffected. Rumen volatile fatty acid ratios, measured in 10 animals, were not affected by monensin treatment and average methane production (323 g/day) was similar for both groups (P=0.961). The absence of benefits from monensin for either production or methane mitigation in dairy cows fed forages as a sole diet are in line with other published data. Monensin CRCs will not provide a profitable route for methane mitigation in ruminants grazed on pasture.}, issn = {1176-5283}, author = {Waghorn GC and Clark H and Taufa V and Cavanagh A} } @conference {41613, title = {In vitro production of volatile fatty acids from forages}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {50-54}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Volatile fatty acid (VFA) production from a range of fresh forages was measured in vitro over 24 hours (h). The forages comprised temperate and tropical grasses, legumes (including some containing condensed tannins; CT), herbs and silages, all of which were minced to resemble chewed forage and incubated in buffered media. Volatile fatty acid concentrations were measured in triplicate for each feed at 0, 6, 12 and 24 h. On average, VFA yields were 131, 226 and 311 mg/g dry matter (DM) between 0 - 6, 0 - 12 and 0 - 24 h, and the highest yields were from legumes (384 mg/g DM) and lowest from plantain (176 mg/g DM) after 24 h. Legumes containing CT produced 28\% less VFA than other legumes. The acetate + butyrate:propionate (A+B:P) ratio showed a substantial difference between forage types, ranging from an average of 2.5 (legumes) to 3.5 (tropical grasses) after 6 h, but differences between forage types diminished after 24 h. Multiple regression analysis showed a weak inverse relationship with NDF (neutral detergent fibre) after 6 h, but there was no clear relationship with particle size, chemical composition or digestion rates at 12 and 24 h. }, issn = {1176-5283}, author = {Burke JL and Waghorn GC and Brookes IM and Chaves AV and Attwood GT} } @conference {41890, title = {Supplementing dairy cows with oils to improve performance and reduce methane ? does it work?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {66}, year = {2006}, month = {Jan}, pages = {176-181}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Napier}, abstract = {Oil supplements can be used in dairy rations to increase dietary energy density (and energy intake) and reduce methane (CH4) emissions from rumen fermentation. Trials at Dexcel measured effects of oil supplementation on dry matter intake (DMI), milk yield and methane production after lactating dairy cows were fed pasture-based diets for short (14-day) and long (12-week) periods. In the short-term trial, 32 cows received either no oil or three mixtures of sunflower and fish oil at 500g/d. In the long-term trial 20 cows grazed pasture and received either no oil or 300g linseed and fish oil for 11 weeks prior to methane measurements. The type of oil in the short-term trial did not affect methane production and oils had no effect on DMI or milk yield but reduced total methane emissions by 27\% (176 vs. 242g CH4/cow/d, sed=10.6) and CH4/kg DM (13.5 vs. 18.5g CH4/kg DM, sed=0.88). In the long-term trial, oil had no effect on methane emissions (353 (oil) vs. 323g CH4/cow/d (control), sed=17.0 and 21.7 vs. 23.0g CH4/kg DM, sed=1.01). These trials did not show benefits of oils for milk production and emphasize the need for longterm studies when developing on-farm strategies for methane mitigation. }, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Thomson NA} } @conference {41835, title = {Condensed tannins in birdsfoot trefoil (Lotus corniculatus) affect the detailed composition of milk from dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {283-289}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Feeding birdsfoot trefoil (lotus, Lotus corniculatus) to dairy cows increases milk solids production and reduces methane production relative to ryegrass pasture. This study has measured the affect of lotus and lotus condensed tannins (CT) on milk protein and lipid composition. The trial involved 32 Friesian dairy cows offered either good quality perennial ryegrass pasture or lotus. Half of the cows given each diet were drenched with polyethylene glycol (PEG) to inactivate the CT. A daily milk sample was collected from all cows prior to and towards the end of the treatment period. Gross milk fat and milk protein concentrations were similar for cows fed lotus or ryegrass. Neither feed, nor CT affected individual proteins in the milk with the exception of lactoferrin (Lf) where the CT in lotus increased concentrations (138 vs 76 mg/l; P < 0.01). Forage type affected the composition of fatty acids (FA) in the milk with cows gazing lotus having higher concentrations of de novo synthesised (C4:0-C15:0; 28.3\% vs 26.7\%; P < 0.01) and lower concentrations of pre-formed (C17:0 and longer; 34.5\% vs 39.0\%; P < 0.05) FA than those grazing ryegrass. The CT in lotus appeared to affect ruminal biohydrogenation of FA, decreasing the concentration of saturated FA in the milk fat, and increasing in the concentrations of the omega-3 FA (1.5\% vs 1.1\%; P < 0.01). Changes in the saturation and proportions of FA may affect processing characteristics and functionality of milk from cows fed lotus. CT in lotus may also provide potential new avenues for increasing milk value on-farm. KEYWORDS: detailed milk composition; Lotus corniculatus; condensed tannins. }, issn = {1176-5283}, author = {Turner S-A and Waghorn GC and Woodward SL and Thomson NA} } @conference {41851, title = {Feeding maize silage to dairy cows : implications for methane emissions}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {356-361}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Maize silage was used on 25\% of New Zealand dairy farms in 2003/2004, with 26\% of these farms feeding 2 t DM/ha as maize silage. The nutritional value and animal responses to maize silage fed with pasture are well defined, but its impact on rumen methane emissions is not. In an 11-day indoor feeding trial, 32 Friesian dairy cows in mid lactation were fed ad libitum pasture with 0, 12, 24 and 36\% of the dry matter (DM) intake supplied by maize silage. Pasture and maize silage intakes, milk production and methane emissions were measured. Half of the cows in each treatment group were given intra-ruminal slow release monensin capsules. Total DM intakes were similar for all feed treatments. As maize silage intake increased, milksolids (MS) production decreased linearly from 1.73 (pasture only) to 1.46 kg/day (P = 0.0043, SED = 0.09) and methane emissions increased from 16.3 to 19.0 g/kg DMI (P = 0.0061, SED = 1.03). Increasing proportions of maize silage in a pasture-based diet increased methane emissions from lactating dairy cows. These effects were alleviated by monensin. KEYWORDS: dairy cows; methane emissions; milk production; perennial ryegrass; maize silage. }, issn = {1176-5283}, author = {Waugh CD and Clark DA and Waghorn GC and Woodward SL} } @conference {41852, title = {Impact of monensin on methane production and performance of cows fed forage diets}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {65}, year = {2005}, month = {Jan}, pages = {362-366}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Monensin is an ionophore used to increase the efficiency of feed utilisation when grain-based rations are fed to beef cattle, but it can also lower energy losses to methane. A series of feeding experiments has been undertaken to measure the impact of monensin on methane production by dairy cows fed ryegrass-dominant pastures alone or with white clover, or maize silage. Methane production measured from 15 sets of identical twin cows fed indoors was reduced by 9\%, from 16.9 to 15.3 g/kg dry matter (DM; P < 0.01), and remained 10\% lower (P < 0.05) than Controls 72 days after the monensin capsule was given. When pasture was substituted with maize silage at 12, 24 and 36\% of DM intake, monensin reduced methane (g/kg DM) by 1, 6.5 and 10.5 \% respectively (P = 0.05). However, methane emissions were not affected in cows fed pasture with white clover at 15, 30 or 60\% of DM intake. Although monensin provides an important opportunity for methane reduction, the data demonstrate a need to understand reasons for variable responses to treatments under differing nutritional regimes. The added benefits of improved feed efficiency and reduced bloat suggest further investigation of monensin for forage fed ruminants is warranted. Keywords: monensin; dairy cows; methane; pasture; white clover; maize silage. }, issn = {1176-5283}, author = {Van Vugt SJ and Waghorn GC and Clark DA and Woodward SL} } @conference {41496, title = {Condensed tannins in birdsfoot trefoil (Lotus corniculatus) reduce methane emissions from dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {64}, year = {2004}, month = {Jan}, pages = {160-164}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {Ruminant methane production contributes 34\% of New Zealand greenhouse gases, but emissions are affected by feed type. A trial conducted at Dexcel measured methane production by 32 Friesian dairy cows grazing either good quality perennial ryegrass pasture or birdsfoot trefoil (lotus, Lotus corniculatus), a legume with high nutritive value that contains condensed tannins (CT; 2.62 g CT/100 g DM). Half the cows on each diet were drenched with polyethylene glycol (PEG) to inactivate the CT and allow the effect of CT on methane production to be determined. Total methane production, measured using the SF6 tracer technique, was similar for the lotus and ryegrass cows (343.2 vs 360.6 g CH4/cow/d; ns), however, methane production per unit DMI was lower from cows fed lotus (19.9 vs. 24.2 g CH4/kg DM, P<0.001). The CT in lotus reduced methane production by 13\% relative to lotus when the CT had been inactivated by PEG, and was responsible for 66\% of the difference between lotus and ryegrass. Cows fed lotus produced 32\% less methane/kg milksolids compared to good quality ryegrass. The feasibility of feeding lotus as a methane mitigation option should now be assessed at a farm systems level to investigate effects on other greenhouse gases, productivity and profitability. }, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Laboyrie PG} } @conference {41413, title = {Empirical assessment of the CNCPS model to predict performance of dairy cows fed pasture with silage supplements}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {91-95}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {The goal of this work was to determine the accuracy and utility of the Cornell Net Carbohydrate and Protein System (CNCPS) model to predict milk production from diets based on pasture and forage supplements. Data were obtained from studies in which pasture was complemented with contrasting silages including maize, pasture, sulla, lotus and forage mixtures, comprising 30-40\% of dry matter intake (DMI). Twelve diets were used in this evaluation. DMI, live weight (LW), days in milk, and diet composition were determined during the trials and used as inputs in the model. Across all diets, a significant (P<0.01) relationship existed between predicted and actual values for DMI (r2=0.63), milk yield (r2=0.64) and LW change (r2=0.57) but there were still large unexplained sources of variation and the slopes of the regression lines were significantly (P<0.01) different than 1. No significant mean bias was observed for any of the variables, but the slope of residual differences against predicted values was significantly different from zero (P<0.01 for milk yield and LW change; P<0.06 for DMI). The results indicate a satisfactory prediction of milk production when cows are neither gaining nor losing weight, but that a systematic bias exists probably because of the CNCPS model{\textquoteright}s failure to account for nutrient partitioning. }, issn = {1176-5283}, author = {Chaves AV and Brookes IM and Burke JL and Waghorn GC and Woodward SL} } @conference {41421, title = {Methane and carbon emissions from conventional pasture and grain-based total mixed rations for dairying}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {63}, year = {2003}, month = {Jan}, pages = {128-132}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Queenstown}, abstract = {Comparisons between cows grazing pasture or fed total mixed rations (TMR) show on average less milk production from pasture but a higher methane yield per milk or milksolids production from the pasture diet. The implication that TMR are associated with relatively lower greenhouse gas (GHG) emissions than pasture required an assessment of all production costs associated with both systems because TMR requires extensive cultivation and processing of grains and silages which form the bulk of the diet. A partial life cycle analysis of GHG (excluding nitrous oxides) was carried out for separate 250 cow herds located in Waikato (pastoral grazing) and Canterbury (cropping land for the TMR). This demonstrated much higher methane and carbon dioxide emissions, (kg CO2 equivalents/kg milk) from cows fed TMR (1.53) relative to pasture (0.84). The principal cause of the high value for TMR were carbon losses from soil cultivation which accounted for 64\% of emissions, expressed as CO2 equivalents compared to 24\% from pasture. Enteric methane accounted for 28\% of GHG from TMR and 64\% from pastoral systems. The remaining 8\% and 12\% from TMR and pastoral grazing respectively, were attributed to fertilisers, cultivation and processing.}, issn = {1176-5283}, author = {van der Nagel LS and Waghorn GC and Forgie VE} } @conference {41319, title = {Ammonia and urea utilisation in lambs infected with Trichostrongylus colubriformis and fed fresh lucerne (Medicago sativa)}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {77-80}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {The effect of a Trichostrongylus colubriformis infections on ammonia and urea fluxes across the mesenteric-drained viscera (MDV), portal-drained viscera (PDV), and liver was investigated using an arterio-venous preparation in lambs fed fresh lucerne (Medicago sativa). The lambs were infected with 6000 T. colubriformis L3 larvae per day for 6 days (n=5) or kept as parasite free controls (n=5). On day 48 of the experiment, the lambs were infused continuously for 8 hours with r-aminohippuric acid (688 mg/h) into the mesenteric vein in order to measure plasma flow across the MDV, PDV and liver. Blood was continuously collected from the mesenteric artery and vena cava for consecutive two hour periods throughout the infusion period and plasma was harvested. Plasma concentrations of ammonia and urea were unaffected by the presence of intestinal parasites. Ammonia fluxes across the MDV, PDV, and liver were similar between treatment groups. Urea fluxes were also similar between treatment groups with the exception of the PDV, which showed a net release of urea in the parasite group and a net uptake by the control group (P=0.03). This suggests that the presence of a sub-clinical T. colubriformis infection does not increase the demand on the lamb for amino acids for ureagenesis. }, issn = {1176-5283}, author = {Bermingham EN and Roy NC and Reynolds GW and Sinclair BR and Peters JS and Sutherland IA and Waghorn GC and Revell DK and McNabb WC} } @conference {41364, title = {Can forages match concentrate diets for dairy production?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {261-266}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Comparisons have been made between concentrate based total mixed rations (TMR) and grass dominant pasture for dairy production. Limitations to further improvement in cow performance have been indicated by the very high reticulo-rumen fill in New Zealand cows fed pasture, exceeding 22\% of live weight, relative to United States cows fed either TMR or forage diets. The importance of high concentrations of structural fibre in ryegrass dry matter, moisture content of fresh forages and the very rapid eating associated with high utilization of pasture on New Zealand dairy farms will limit increases in feed intake and cow performance. Responses to ryegrass supplementation with high quality forages have been summarised together with suggestions for future research and farming systems to improve performance and profitability of cows fed forage diets.

}, issn = {1176-5283}, author = {Waghorn GC} } @conference {41353, title = {Dairy industry perspectives of methane emissions and production from cattle fed pasture or total mixed rations in New Zealand}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {213-218}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

This paper examines the significance of ruminant methane emissions for the NZ dairy industry at a time when NZ is about to ratify the Kyoto Protocol. We consider factors for practical methane mitigation, and a broad based research strategy for the development of measures to reduce methane emissions. A key factor in the process is the integration of methane mitigation research into existing research programs. We were able to incorporate methane measurements into a trial evaluating the performance of two dairy cow genotypes fed contrasting diets. Overseas genotypes produced 8-11\% less methane, as a percentage of gross energy (GE) intake, compared to New Zealand genotypes and total mixed rations (TMR) resulted in similar energy losses to methane (\% of GE) as pasture.

}, issn = {1176-5283}, author = {Robertson LJ and Waghorn GC} } @conference {41338, title = {Digestion kinetics of ryegrass}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {157-162}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Changes in ryegrass maturation, with accompanying decreases in nutritive value and feed intake, have significant consequences for the dairy industry. Thus digestion kinetics of ryegrass were measured in samples differing in both physiological age (days after cutting) and calendar date to form a database that can be used as a guide to calculate the extent and type of supplement needed to match nutrient supply with requirements of grazing dairy cattle. Ryegrass pasture was mown on 21 August, 11 September, and 21 September and samples of approximately 2 kg were harvested from those dates at 7-14 day intervals for chemical analyses by cutting to 5 cm above soil level. These samples were used for in sacco and in vitro incubations to determine rate of digestion and proteolysis. The principal finding was a rapid decline in crude protein content from about 22.5\% of DM harvested at 21 days to 7.2\% for that harvested after 67 days. These changes were associated with increases in the neutral detergent fibre (NDF) fraction of the DM (42.1\% to 56.3\%) and in lignin concentration (2.49\% to 3.07\%). Changes were more rapid in late-cut than early cut forages. The principal consequences of increased maturity were slower degradation rates of DM (k= 0.067 to 0.038/hour) and CP (k= 0.122 to 0.052/hour) and less degradation of crude protein to ammonia. This data can be used in conjunction with dairy cow models (e.g., CNCPS) to predict animal performance. }, issn = {1176-5283}, author = {Chaves AV and Waghorn GC and Brookes IM and Hedderley D} } @conference {41356, title = {Does feeding sulla (Hedysarum coronarium) reduce methane emissions from dairy cows?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {227-230}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

Most of New Zealand\’s methane is generated as a by-product of feed fermentation in the rumen of livestock and is released through the mouth and nose. An experiment conducted in late summer using Friesian and Jersey dairy cows investigated whether feeding sulla (Hedysarum coronarium), a condensed tannin (CT)-containing legume, reduced methane emissions without compromising milksolids production. Cows grazing sulla had higher intake (DMI; 13.1 vs. 10.7 kg DM/cow/d, P\<0.001) and milksolids production (1.07 vs. 0.81 kg MS/cow/d, P\<0.001) than cows grazing perennial ryegrass pasture. Total daily methane emissions were similar (253.9 vs. 260.0 g CH4 /cow/d, ns). However, cows fed sulla produced less methane production per unit DMI (19.5 vs. 24.6 g CH4 /kg DM, P\<0.05) and per unit milksolids yield (243.3 vs. 327.8 g CH4 /kg MS, P\<0.01) than those fed ryegrass due to the higher nutritive value of sulla compared with the ryegrass, and possibly the presence of CT. Further research will determine whether feeding alternative, high quality forages is a viable methane mitigation option for New Zealand dairy farm systems, but results of this study clearly indicate that CT-containing legumes, such as sulla, do effectively reduce methane emissions from dairy cows without compromising milksolids production.

}, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Lassey KR and Laboyrie PG} } @conference {41337, title = {An evaluation of sulla (Hedysarum coronarium) with pasture, white clover and lucerne for lambs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {152-156}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {Pasture-based diets restrict animal performance, due to limitations in voluntary feed intake and release of nutrients during digestion failing to meet nutrient requirements. Opportunities for improving the efficiency of pasture utilisation include the addition of a soluble carbohydrate source to enable an improved capture of ammonia by rumen bacteria, or the inclusion of condensed tannins (CT) to reduce protein degradation. A feed evaluation trial was conducted at AgResearch Grasslands to investigate the ability of sulla, a forage containing high concentrations of soluble carbohydrate and CT, to complement pasture and legume species. Fifty-six weaned ram lambs were allocated to seven diets: pasture (80\% ryegrass and 20\% white clover), white clover, lucerne, sulla, and 50:50 mixtures (DM basis) of pasture:sulla, white clover:sulla and lucerne:sulla. Lambs fed sulla, white clover, white clover:sulla and lucerne:sulla had the most rapid daily gains (256-263 g/day) while lambs fed pasture gained 105 g/day, respectively. Wool growth was influenced by diet. Sulla added to pasture, white clover and lucerne diets significantly reduced rumen ammonia concentrations and acetate:propionate ratios in lambs. Lamb performance can be improved by combining sulla with pasture and lucerne, and rumen parameters can be used to explain animal performance differences. }, issn = {1176-5283}, author = {Burke JL and Waghorn GC and Brookes IM} } @conference {41365, title = {Improving animal performance using forage-based diets}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {62}, year = {2002}, month = {Jan}, pages = {267-272}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Palmerston North}, abstract = {

New Zealand livestock systems are based on ryegrass dominant pastures, but they are unable to maximise animal production. Limitations of ryegrass-based pastures are reviewed, and opportunities for using alternative forage species to complement pasture and improve animal production are discussed. Ryegrass pastures have low dry matter contents and high fibre concentrations which restrict feed intake so animal energy requirements are often not met. High crude protein (CP) concentrations in spring and rapid proteolysis in the rumen produces excess ammonia which must be excreted, whereas summer pastures contain insufficient CP. Chicory, red clover, lotus species, sulla, lucerne and maize silage are examples of forages that can complement ryegrass to improve animal performance. More information is needed to define digestion and fermentation of fresh forages in the rumen, but in vitro and in sacco techniques have been used to evaluate these parameters for grasses, legumes, herbs and silages. This information with feed composition data will be used in computer simulations to predict forage mixtures able to complement pasture at different times of the year. The challenge will be to complement the changing ryegrass pastures with other forages to improve animal welfare, productivity and profit.

}, issn = {1176-5283}, author = {Burke JL and Waghorn GC and Chaves AV} } @conference {41231, title = {Digestion kinetics of mature grasses}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {61}, year = {2001}, month = {Jan}, pages = {8-12}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Digestion kinetics were measured for mature (green and non-senescent) components of five grass species using in sacco and in vitro incubations to define rates of degradation and nutrient release. The data will be incorporated into a dairy nutrition simulation model to identify limitations in nutrient supply to cows grazing mature pasture in late spring. Perennial ryegrass, tall fescue, Yorkshire fog, phalaris and paspalum were hand separated into leaf, stem and inflorescence for incubations. Percentages of fibre (NDF) in DM fractions ranged from 50-69\% (leaf), 63-75\% (stem) and 50-68\% (inflorescence). Crude protein concentrations in the DM of the respective fractions were 7.5-23.7\%, 3.8-8.3\% and 7.9-12.3\%. Soluble DM (\% of the total) determined after mincing accounted for 31-53\% of leaf, 26-55\% of stem and 20-48\% of inflorescence, and fractional (h-1) degradation of the insoluble DM was very slow, ranging from 0.034-0.113 (leaf), 0.025-0.036 (stem) and 0.033-0.072 (inflorescence). After 24 hours of in vitro incubation plant nitrogen content become limiting for fermentation in most instances. }, issn = {1176-5283}, author = {Chaves AV and Waghorn GC and Brookes IM and Burke JL} } @conference {41235, title = {Early indications that feeding Lotus will reduce methane emissions from ruminants}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {61}, year = {2001}, month = {Jan}, pages = {23-26}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Christchurch}, abstract = {Ruminant livestock produce at least 75\% of New Zealand{\textquoteright}s total methane emissions and are a major contributor of greenhouse gas emissions. Most ruminant methane arises from microbial activity in the rumen (methanogenesis) and is released through the mouth and nose. Methane production per unit feed intake or per unit production can be reduced by improving diet quality, for example, including legumes in a pasture diet. A preliminary investigation with wether sheep showed lower daily methane outputs per unit dry matter intake (DMI) when fed Lotus pedunculatus (a condensed tannin-containing legume) than ryegrass-based pasture or lucerne (14.5 vs. 20.4 vs. 19.0 gCH4/kg DMI). Friesian dairy cows fed either Lotus corniculatus silage or perennial ryegrass silage had similar total methane outputs (376.7 vs. 344.4 g CH4/cow/day; ns). However, methane emissions were lower from cows fed Lotus silage when expressed per unit DMI (26.90 vs. 35.13 g CH4/kg DMI; P<0.001) and per unit production (378 vs. 434 g CH4/kg milksolids; P<0.05) as a result of the higher intake and milksolids yield. The mitigation of methane emissions from animals fed Lotus species was due in part to a higher nutritive value relative to pasture but effects of condensed tannins on methanogenesis warrants further investigation. }, issn = {1176-5283}, author = {Woodward SL and Waghorn GC and Ulyatt MJ and Lassey KR} } @conference {41147, title = {Formulating total mixed rations from forages - defining the digestion kinetics of contrasting species}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {9-14}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {The work described here is the first step in formulating forage-based TMR rations for dairy cows, based on digestion kinetics derived from in vitro and in sacco incubations. Kinetic information has been obtained from 23 contrasting fresh and conserved forages species, including temperate and tropical grass species, legumes (including Lotus spp. containing condensed tannins), herbs, silages, lucerne hay and maize grain. All forages were minced to a particle size similar to chewed material. Estimates of DM solubility (\% DM) and fractional dry matter degradation rates (h-1) determined by in sacco incubations include: white clover (39\%, 0.195), perennial ryegrass (45\%, 0.114), tall fescue (46.8\%, 0.051), paspalum (27\%, 0.068), sulla (51.4\%, 0.121), chicory (41.8\%, 0.260), pasture silage (41\%, 0.083), maize silage (28\%, 0.042). In vitro incubations resulted in five-fold differences between forages in net ammonia release, 2-3 fold differences in volatile fatty acid yield and a three-fold difference in acetate:propionate ratio. The data will be used in simulation models to identify optimal forage mixtures for meeting the nutritional needs of high-producing dairy cows. }, issn = {1176-5283}, author = {Burke JL and Waghorn GC and Brookes IM and Attwood GT and Kolver ES} } @conference {41146, title = {Preparation of fresh forages for incubation and prediction of nutritive value}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {60}, year = {2000}, month = {Jan}, pages = {5-8}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, address = {Hamilton}, abstract = {In vitro and in sacco digestion offers a rapid and inexpensive method for evaluating nutritive value of ruminant feedstuffs. This study compared the conventional freeze dried and ground (FD) preparation with chopping to 6-mm lengths (C) and mincing (M) to represent chewed forage. In sacco and in vitro comparisons were made with perennial ryegrass (RG), white clover (WC) and Lotus corniculatus (LC). The mean proportions of large (>1.0mm) and soluble dry matter (DM) for the three forages were: M, 0.38 and 0.44; C, 0.76 and 0.21; FD, 0.35 and 0.34 respectively. Disappearance of DM and crude protein (CP) during the first 12 hours of rumen incubation was substantially lower for chopped forages. Minimal lag times before the onset of protein degradation were observed following mincing. Yields of ammonia from proteolysis in in vitro incubations were lowest for C and usually highest for M preparations. Preparation also affected yield but not proportions of VFA. These data show that ranking of forages for digestibility is affected by preparation and mincing appears to be a more suitable preparation for assays than chopping and freeze drying and grinding. }, issn = {1176-5283}, author = {Barrell LG and Burke JL and Waghorn GC and Attwood GT and Brookes IM} } @conference {41024, title = {Effect of pasture supplemented with methionine on wool growth and selected growth parameters}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {58}, year = {1998}, month = {Jan}, pages = {189-191}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {The effects of a supplemental oral drench of rumen-protected methionine (Mepron{\textregistered}) on wool growth and weight gain was studied in 2-3y non-mated Romney ewes during nine months from March to December. Three groups of 20 sheep received either 0, 4 or initially 8 (later 2) g of methionine daily. The ewes were rotationally grazed as a single mob on ryegrass-white clover pasture with winter restrictions. Pasture availability was monitored weekly. Mid-side wool samples were taken at two-monthly intervals and analysed for yield. Full fleece samples were collected during end of trial shearing and analysed for yield, fibre diameter, colour, staple length, crimp and style. Sheep were weighed weekly and herbage intakes estimated in August and November. Blood samples for plasma cysteine determinations were collected in June, August and November. There were no significant differences between the control and 4g/d groups in clean wool growth from mid-side patches (mean 1260 mg/cm{\texttwosuperior}/d), greasy fleece weight (4.12kg) or final live-weights (63.1kg). Average estimates of pasture intake were non-significantly lower in supplemented sheep in August but approached significance in November (P<0.11). There were no treatment effects on wool growth rate or wool characteristics even though Mepron increased (P<0.05) plasma cysteine concentrations (umolar) (control 40.5 vs 4g/d 45.3) in June and in August (25.9 vs 31.1) but not in November. Weight-adjusted back-fats depths were lower in both supplemented groups compared to controls (P<0.05). We conclude that simple deficiencies in sulphur-containing amino acids were not limiting for wool production in these grazing sheep. }, issn = {1176-5283}, author = {Purchas BJ and Waghorn GC and Wickham GA} } @conference {40800, title = {Effect of iodine supplementation on milk iodine concentrations and productivity of dairy cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {56}, year = {1996}, month = {Jan}, pages = {143-145}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Iodine (I) concentrations in New Zealand pastures are low and may be inadequate to meet the I requirements of lactating dairy cows. A trial was undertaken with 400 cows to determine the effects of a single intra-muscular injection of 2000 mg I (in popyseed oil) given at the beginning of lactation on cow performance. The pasture I concentration ranged between 0.17-0.26 mg I/kg DM during of the trial and the supplement increased serum thyroxine (T4) and milk I concentrations for 76 (P<0.05) and 170 (P<0.01) days respectively. Iodine supplementation did not affect milk yield milk composition or number of services per conception. To increase I status and maintain milk I concentrations at or above 40 }, issn = {1176-5283}, author = {Grace ND and Waghorn GC and Mills AR and Death AF} } @conference {40711, title = {The effect of six herbages on liveweight gain, wool growth and faecal egg count of parasitised ewe lambs}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {55}, year = {1995}, month = {Jan}, pages = {199-201}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Robertson HA and Niezen JH and Waghorn GC and Charleston WAG and Jinlong M} } @conference {40603, title = {The effects of condensed tannin in Lotus corniculatus upon nutrient metabolism and upon body and wool growth in grazing sheep.}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {54}, year = {1994}, month = {Jan}, pages = {219-222}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Lotus corniculatus containing 23 g/kg DM of extractable condensed tannin (CT) and 35 g total CT/kg DM was fed to sheep in two experiments. In both experiments half the sheep received supplementation with polyethylene glycol (PEG), which binds and inactivates CT, enabling the effects of CT to be quantified by comparing control sheep (CT operating) with PEG sheep (CT inactivated). Experiment 1 was conducted indoors, with sheep held in metabolism crates and fed hourly to determine the effects of CT upon apparent digestibility and upon plasma irreversible loss (IRL) rates of methionine, cystine and inorganic sulphate, using 35S labelling. Experiment 2 as a field trial with weaned lambs given a restricted allowance of either lotus corniculatus (CT-containing) or lucerne (non CT-containing), with or without PEG supplementation. In Experiment 1, CT slightly lowered the apparent digestibility of organic matter (0.77 vs 0.80; P<0.1), hemicellulose (0.61 vs 0.67; P=0.118) and markedly reduced nitrogen apparent digestibility (0.72 vs 0.80; P<0.01), but had no effect upon cellulose digestibility. CT increased the IRL of plasma cystine (13.1 vs 7.0 mmol/min; P<0.05) and reduced the IRL of plasma inorganic sulphate (36.8 vs 48.1 mmol/min; P<0.01) but had no effect upon plasma methionine IRL. In Experiment 2, live weight gain and wool growth were similar for sheep grazing lucerne (with and without PEG supplementation) and for sheep grazing lotus with PEG supplementation. In sheep grazing lotus, action of CT increased wool production (12.1 vs 10.9 g/d; P<0.05) and slightly increased live weight gain (203 vs 188 g/d; P=0.07). These experiments showed that CT in Lotus corniculatus increased the amount of cystine available for body synthetic reactions and increased wool growth.}, issn = {1176-5283}, author = {Wang Y and Waghorn GC and Douglas GB and Barry TN and Wilson GF} } @conference {40537, title = {A comparison of carcass and meat characteristics and organ weights of castrate and entire male buffalo and cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {407-412}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Research has shown that sheep from a Massey University flock selected for increased fleece weight (FW) for thirty-six years have higher faecal egg counts (FEC) than unselected controls (C). The purpose of this trial was to determine whether differences in FEC between FW and C sheep accurately reflected differences in adult worm burdens. In addition levels of mucosal mast cells, and their relationship with worm burden in each line were examined. Thirteen one year-old rams from each flock were housed indoors and artificially infected with larvae of three species of nematode parasite: Haemonchus contortus, Ostertagia circumcincta, and Trichostrongylus colubriformis. FECs were monitored and adult worm burdens, and levels of mucosal mast cells, determined following slaughter 28 days after infection. FECs were higher in FW than C sheep (4204 vs 300 epg, p<0.0001), as were numbers of adult Haemonchus (1151 vs 249, p<0.01) and Ostertagi (2268 vs 600, p<0.05). Numbers of Trichostrongylus (5838 vs 5266) and total worm burden (9257 vs 6115) were not significantly different between lines. A {\textquoteright}Total Pathogenic Index{\textquoteright}, calculated from the number of parasites of each species present in the total burden, was higher in FW than C sheep (3.8 vs 1.5, p<0.005). The regression coefficient relating FEC to worm burden was larger in FW than C sheep (0.35 vs 0.05 eggs per g faeces/worm, p<0.01). Levels of mucosal mast cells did not differ significantly between lines, but were inversely related to number of worms in FW sheep. There was no such relationship in C sheep. It is concluded that while the large differences in FEC between lines overestimates the difference in total worm burden, FW sheep do carry significantly more worms of the abomasal species H. contortus and O. circumcincta than C sheep. FW sheep are able to maintain superior wool production in spite of this potentially more pathogenic worm burden. The mucosal mast cell response to parasitic infection also appears to have been changed by selection. }, issn = {1176-5283}, author = {Purchas RW and Thomson NA and Waghorn GC and Death AF} } @conference {40497, title = {Internal parasites and lamb production - a role for plants containing condensed tannins?}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {53}, year = {1993}, month = {Jan}, pages = {235-238}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {An intensive evaluation of the hormones that are primarily involved in regulating reproductive function in cows treated with progestins was undertaken and comparisons were made to cows with a functional corpus luteum. Cows with a functional corpus luteum were found to have reduced circulating luteinizing hormone (LH) and oestradiol than cows treated with a single progesterone releasing intravaginal device (PRID), norgestomet (progestin used in Syncro-Mate-B synchrony) or melengestrol acetate (progestin used for oestrous synchrony in the USA). If greater doses of progesterone than that released from a single PRID are used, concentrations of LH and oestradiol are like those of control cows in the midliteal phase of their oestrous cycle. In addition, conception rates are significantly improved when greater doses of progesterone are used compared to that of cows in which oestrus is synchronised with a single PRID. We propose that one reason for reduced conception with oestrous synchrony programmes presently in use is the failure of the progestins to effectively mimic the function of the corpus luteum.}, issn = {1176-5283}, author = {Niezen JH and Waghorn TS and Waghorn GC and Charleston WAG} } @conference {40384, title = {The nutritive value of Lotus for sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {52}, year = {1992}, month = {Jan}, pages = {89-92}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A large-scale screening operation over two seasons by Landcorp Farming Ltd has established a terminal sire-breeding programme for sheep. Within the North and South Islands, screened hoggets were transferred to Huirimu Station and Kepler Station respectively. In 1989, 2,046 ewe hoggets (0.8\%) were screened on liveweight from 248,500 animals in 114 flocks. Mean pooled population weight (adjusted to 18 December) was 43.2 }, issn = {1176-5283}, author = {Waghorn GC and Shelton ID} } @conference {40199, title = {Nutritional partitioning of growth for productive gain}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {50}, year = {1990}, month = {Jan}, pages = {81-90}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Artificial insemination (AI) is widely used throughout New Zealand dairy herds because it is convenient and allows herd owners to utilise semen from intensively selected genetically superior sires. The future focus of AI use will be to synchronise oestrus in maiden heifers and cows to further concentrate seasonal calving patterns. There will also be continued use of progesterone-based treatments to stimulate ovarian activity in anoestrous cows and to increase pregnancy rates in inseminated cows. Aspects of behaviour and marked seasonality in red deer and fallow deer currently present challenges to increasing the use of AI and controlled breeding in these species. It would be preferable to have fawning/calving in spring instead of summer, with or without the use of AI. However, the semen production of stags is best from 4 weeks after the onset of the induced or normal rut. This potentially increases the dependence on deep frozen semen and increases the need for the uterine deposition of sperm to increase sire coverage and achieve satisfactory pregnancy rates. Controlled use of hormones will produce altered calving/fawning dates and developing semen collection/processing techniques will increase the use of AI in deer. }, issn = {1176-5283}, author = {Harris PM and Waghorn GC and Lee J} } @conference {40110, title = {Components of foam and liquor from the rumen of bloating and non-bloating cows}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {48}, year = {1988}, month = {Jan}, pages = {151-156}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {There is strong evidence that growth hormone (GH) does not enhance lactation through a direct effect on the udder but rather that the effect is mediated by insulin-like growth factors (IGF) -I an/or IGF-II produced by the liver. While plasma IGF-I concentrations rose following GH injection of dairy cows and goats, intravenous infusion of goats with IGF-I did not increase milk yield. However, GH treatment increased the relative binding of IGF-I to a high molecular weight binding protein in plasma. Plasma binding proteins may crucially affect the transport of IGF{\textquoteright}s from plasma to tissues. Plasma IGF-II concentrations doubled during GH treatment of lactating goats. In view of the increased presence of IGF-II receptors in mammary tissue during lactation it is possible that plasma IGF-II is involved in mediation of the GH effect on lactation. The increased partition of nutrients for milk synthesis achieved during GH treatment is facilitated by increased blood flow to the udder. There is little change in the plasma concentration of substrates for milk synthesis. It is likely that the increased blood flow occurs as a metabolic consequence of increased milk synthesis.}, issn = {1176-5283}, author = {Waghorn GC} } @conference {40045, title = {Nutritive value of Lotus corniculatus L. containing low and medium concentrations of condensed tannins for sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {47}, year = {1987}, month = {Jan}, pages = {25-30}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {A linear programming model has been developed which allows investigation of alternative dairy production systems. Simulation models used in conjunction with the linear programming model were then used to help set performance standards for on farm animal productivity. Information from these model sources is seen as an aid to decision making on farms and as an opportunity for managers to better understand the basic relationships that apply within their farming system.}, issn = {1176-5283}, author = {Waghorn GC and John A and Jones WT and Shelton ID} } @conference {39988, title = {The effect of different protein/energy intakes on nutritional and physiological parameters in young sheep}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {46}, year = {1986}, month = {Jan}, pages = {31-36}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Five Poll Dorset breeders have co-operated since 1982 in a progeny-testing programme to improve lean meat production in their respective flocks. Ram lambs were selected from each flock on their BV{\textquoteright}s for weaning weight (in 4 of the 5 flocks) and were then assessed for fatness (visually and tactually initially, and finally by ultrasonic probe), structural soundness, and muscling. The ram lambs selected for the progeny test were mated at random to Coopworth mixed-aged ewes on a commercial prime lamb property. The progeny were identified to sire and dam and their birthrank indicated by ear-tag. Only progeny born during a 6- to 7-day period were identified in this way. At slaughter in November, information on export grade, carcass weight, and GR measurement was obtained. Heritabilities of carcass weight (CWT) and GR measurement adjusted for carcass weight (AGR) were respectively 0.20 and 0.29 and the genetic correlation between them was -0.09 (based on 29 sires and 490 progeny). To rank the sires, data were analysed on 3 criteria: AGR: carcass lean index (CLI); and a selection index (SI) which included estimates of the relative economic values of carcass weight and GR measurement. Use of CLI was expected to produce the greatest gain in CWT, but least reduction in GR while AGR gave the largest reduction in GR but little gain in CWT. Use of SI would result in intermediate gains in both traits and would achieve the highest increase in financial return carcass.}, issn = {1176-5283}, author = {Waghorn GC} } @conference {39915, title = {Theoretical considerations for partitioning nutrients between muscle and adipose tissue}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {44}, year = {1984}, month = {Jan}, pages = {193-200}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, abstract = {Calorimetry apparatus was used to measure CO2 production and oxygen consumption in 2 Romney and 2 Southdown ewes. Each pair consisted of a long-lean ewe and a short-fat ewe as determined from previous records of height, length, weight and ultrasonic back fat thickness. The respiratory exchange ratio (RER) was calculated as the ratio of CO2 produced/d to O2 consumed/d. When the 4 ewes were fed, the RER remained about 1, characteristic of the oxidation of glucose and short chain fatty acids. When the ewes were fasted for 4 to 5 days the RER declined in a straight linear fashion with time. This is consistent with the mobilisation of long chain fatty acids. The ewes of fatter genotypes exhibited significantly steeper regressions of RER on time.}, issn = {1176-5283}, author = {Waghorn GC and Wolff JE} } @conference {39561, title = {Rumen motility in sheep and cattle as affected by feeds and feeding}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {37}, year = {1977}, month = {Jan}, pages = {176-181}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Waghorn GC and Reid CSW} } @conference {39454, title = {Progress in identifying sources of animal variation in susceptibility to bloat}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {35}, year = {1975}, month = {Jan}, pages = {13-20}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Reid CSW and Gurnsey MP and Waghorn GC and Jones WT} } @conference {39424, title = {Nutritive characteristics of maize silage and maize silage/grass rations for cattle}, booktitle = {Proceedings of the New Zealand Society of Animal Production}, volume = {34}, year = {1974}, month = {Jan}, pages = {78}, publisher = {New Zealand Society of Animal Production}, organization = {New Zealand Society of Animal Production}, issn = {1176-5283}, author = {Waghorn GC and Wilson GF} }