@article {3672,
	title = {Effect of concurrent pregnancy on the persistency of lactation in dairy cows milked once a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {99-105},
	address = {Online},
	abstract = {Persistency of lactation is a trait of economic importance in any dairy production system. The objective was to investigate the effect of concurrent pregnancy on the persistency of lactation in a commercial herd of dairy cows milked once a day. The data set included 1962 monthly herd-test records (total 8-9 tests per cow) of milk, fat, protein and lactose yield from 219 pregnant cows and 23 non-pregnant cows of different breeds and lactation number. The records were used to model lactation curves for pregnant and non-pregnant cows using random regression with a linear model (Wilmink function). This was not an experiment initially designed to examine the effects of pregnancy on persistency of lactation in dairy cows. Rather, in the course of normal farm operations, some cows became pregnant during lactation and others did not. Pregnancy did not affect the persistency of lactation of cows milked OAD. After conception, there was no difference in total yields between the two groups, but there was a trend that pregnant cows produced lower yields of fat (P=0.0519) and lactose (P=0.0884). This difference between our results and those of previous studies was probably because our cows were only milked once a day or because the data set was not suitable for testing the hypothesis. Further study is required to investigate persistence of lactation in pregnant and non-pregnant cows milked OAD.

Keywords: pregnancy; lactation persistency; cows milked once a day},
	issn = {1176-5283},
	author = {Fu Y and Peterson SW and Lopez-villalobos N}
}
@article {3672,
	title = {Temperament of hand-reared beef-cross-dairy cattle does not influence production traits},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {81},
	year = {2021},
	month = {01/2022},
	pages = {57-62},
	address = {Online},
	abstract = {Abstract
Evaluation of temperament of calves early in life is associated with growth and meat quality in extensively farmed beef cattle. However, the relationship between temperament and performance is unclear for hand-reared beef-cross-dairy calves. This experiment analysed temperament of 1077 Angus- and Hereford-sired cattle born to dairy-breed cows and hand-reared, and evaluated the value of these measurements as predictors of growth and meat quality traits. Cattle in this study were calm, with mean exit velocity (EV) between 0.76 and 1.15 m/s from 200 d to 800 d, crush score (CS) between 1.38 and 1.79 from 200 d to slaughter (1-5 scale), and measurements were highly correlated at all ages (P<0.05). Temperament at 200 d and 400 d was not related to growth, but CS was related to growth from 600-800 d (-0.011 kg/d for a 1-point increase in CS at 600 d, P<0.05). Temperament at 800 d or before slaughter was not related to meat ultimate pH or colour score. The small variation in temperament among animals was probably the consequence of cattle being acclimatised to the presence of humans due to hand-rearing and frequent handling. Therefore, temperament is unlikely to be an issue in hand-reared beef-cross-dairy cattle and should not influence growth and meat quality traits.
Keywords: Artificial rearing; beef-on-dairy; beef production; crush score; exit speed; exit velocity; flight time},
	issn = {1176-5283},
	author = {Martin NP and Schreurs NM and Morris ST and Lopez-villalobos N and McDade JL and Hickson RE}
}
@article {3672,
	title = {Genetic evaluation for farm profitability in a commercial grazing dairy herd of Uruguay},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {55-59},
	address = {Online},
	abstract = {The objective of this study was to develop a genetic evaluation model for farm profitability in a seasonally calving pasture-based
dairy herd in Uruguay using crossbred cows. Total lactation yields of milk (MILK), fat (FAT) and protein (PROT) were calculated
for each cow-lactation using the test-interval method. Somatic cell score (SCS) was calculated as the average of log2 (somatic cell
count) for each cow-lactation. Mating records were used to calculate days from start of mating to conception (SMCO). Cow live
weight (LWT) was recorded once per lactation. Cows were scored annually for udder depth (UD), udder support (US), front and
rear teat placement (FT and RT). In total there were 4,081 lactations from 2,371 cows recorded from 2015 to 2017. The cows were
the progeny of 97 sires. Breeding values (BV) for MILK, FAT, PROT, LWT, SMCO, SCS, UD, US, FT and RT were estimated
with a multi-trait repeatability animal model that included the fixed effects of contemporary group (year-lactation number) and
deviation from median calving date, and the random effects of animal, cow permanent and residual error. Estimates of BVs for
these traits were combined in a selection index to rank cows for farm profitability. The index was calculated as I= {\textendash}0.074{\texttimes}BVMILK
+2.13{\texttimes}BVFAT +7.25{\texttimes}BVPROT {\textendash}1.48{\texttimes}BVLWT {\textendash}3.60{\texttimes}BVSMCO {\textendash}36.84{\texttimes}BVSCS +30.86{\texttimes}BVUD +19.67{\texttimes}BVUS +21.10{\texttimes}BVFT +20.07{\texttimes}BVRT.
The index has been used to select the best cows as mothers of future replacements, cull the cows with the lowest selection index
value, and for the selection and culling of heifer replacements.
Keywords: genetic evaluation; genetic parameters; selection index; Uruguay},
	issn = {1176-5283},
	author = {Laborde D and Lopez-villalobos N}
}
@article {3672,
	title = {Genetic parameters, breed and heterosis effects for conformation scores in cows milked once a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {51-54},
	address = {Online},
	abstract = {The use of conformation traits to aid selection for functional cows becomes more important as once-a-day (OAD) milking for
whole or part season becomes more common. In 2013, Massey University Dairy 1 farm transitioned their mixed-breed herd milked
twice-a-day (TAD) to an OAD spring-calving system. All cows on the farm were scored for 14 inspector-scored type traits and
four farmer-scored traits, for a total of 1,617 lactation records over seven seasons (2013-2019, 168 to 258 cows per year). Genetic
parameters, breed and heterosis effects were obtained from an animal model that included the fixed effects of year of scoring and
cow age at scoring, and the covariates of proportion Holstein-Friesian, heterosis between Holstein-Friesian and Jersey, and the
random effects of permanent environment of cow and random additive genetic effect of animal. Stature and live weight were found
to have the greatest heritability estimates (0.46 and 0.41 respectively), while leg angle and body condition score had the lowest
(0.03 and 0.04 respectively). Breed had a significant effect on all type scores, with heterosis also having significant effects; this
is an important consideration with the increasing importance of type scores for cows in OAD milking systems. Jersey cows had
greater front udder and udder support scores than did Holstein-Friesians (P<0.05), while Holstein-Friesians had greater stature and
liveweight scores (P<0.05). From this study, genetic selection for improved udder conformation would see beneficial gains over
time, whilst body condition score is heritable, would not be similarly improved.

Keywords: Traits other than production; once-a-day milking; genetic parameters},
	issn = {1176-5283},
	author = {Sneddon NW and Donaghy DJ and Lopez-villalobos N}
}
@article {3672,
	title = {Milk composition and productive and reproductive performance of cows from A1 and A2 β-casein variants, milked once or twice a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {137-142},
	address = {Online},
	abstract = {Protein is an important component of milk and it plays an essential role in all living organisms. β-casomorphins-7 (BCM-7) is
derived from A1 β-casein and has been implicated in some human health issues. This A1 β-casein is produced by cows with the
A1A1 or A1A2 genotype, whilst cows with the A2A2 genotype produce A2 β-casein, which has not been implicated in the same
human health issues. Given the potential importance of A2 milk for public health and its apparent commercial potential, selection
based on the A2 genotype and its impact on production and reproduction traits should be investigated. The objective of the current
study was to compare the productive and reproductive performance of dairy cows based on A2 genotype in two different dairy
farms. From July 2017 to May 2018, 206 cows (including 122 A2A2 genotype; {\textquotedblleft}A2 cows{\textquotedblright}) were milked once a day at Dairy 1
and 451 cows (including 217 A2 cows) were milked twice a day at Dairy 4. Records of lactation yields of milk, fat and protein,
fat percentage, protein percentage, days from start of mating to conception, pregnancy rate to first service, the submission rate
at 21 days and the pregnancy rate at 21 and 42 days (PR42) after the start of mating from 642 cows in two herds were analysed.
The effects of A2 genotype on production and reproduction traits were not significant. The interaction between farm and β-casein
genotype was significant for PR42 (P<0.05) but not for any other traits. The interactions between parity number and genotype
were not significant for any of the traits. The results indicated that cows of different β-casein genotypes have similar production
and reproductive performance.
Keywords: β-casein genotype; A2 milk; protein percentage; pregnancy rate at 42 days},
	issn = {1176-5283},
	author = {Lu Y and Hickson RE and Gedye K and Correa-Luna M and Donaghy DJ and Lopez-villalobos N}
}
@article {3672,
	title = {Persistency and lactation curves modelled using nonlinear random regression in dairy cows milked once a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {131-136},
	address = {Online},
	abstract = {Modelling lactation curves of dairy cows is important for improved feed management and breeding decisions. The objectives
of this study were to compare measures of lactation persistency obtained from the modelling of lactation curves for daily yields
of milk, fat and protein using a nonlinear random regression model in dairy cows milked once a day under grazing conditions.
A total of 1,955 monthly herd-test records of milk, fat and protein from 55 Holstein-Friesian (F), 64 Jersey (J), and 123 F{\texttimes}J
crossbreds of different lactations were used to obtain lactation curves for each cow using a random regression model with the
Wood function. Three measures of persistency were calculated based on ratios of yields and compared with persistency calculated
based on parameters of the Wood function. Jersey cows in lactation 3 had the greatest persistency for all persistency measures. In
first-lactation cows, there were no significant breed differences in persistency. Persistency measures were strongly correlated with
each other (r>=0.97; P<0.001). The conclusion from this study is that parameters of the lactation curve (peak yield, day of peak and
persistency) can be precisely estimated using the random regression model with the Wood function.

Keywords: modelling; lactation curve; persistency; once-a-day milking},
	issn = {1176-5283},
	author = {Jiang H and Hickson RE and Woods OT and Morandeau M and Burke JL and Correa-Luna M and Donaghy DJ and Lopez-villalobos N}
}
@article {3672,
	title = {Associations of body condition score and change in body condition score with lamb production in New Zealand Romney ewes},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {91-94},
	address = {Palmerston North},
	abstract = {Body condition score (BCS) is an on-farm subjective measurement used to inform feed management decisions in sheep. This study determined the associations of BCS and changes in BCS on production. Ewe BCS was recorded four times annually in a flock of 2534 Romney ewes aged one-five, first bred at eight-months of age. Production was measured as the number of fetuses scanned (NLS), number of lambs weaned (NLW), average weight of lambs weaned (WWT) and total weight of lamb weaned (TLW). Ewe BCS was greatest at lambing and lowest at weaning. At pregnancy scanning (at an average of 75 days of pregnancy),  two weeks prior to lambing, and at weaning, BCS >=4.5 was associated with the lowest NLS and NLW, but the greatest WWT. Ewes with a BCS <=2.5 at weaning were associated with the greatest TLW, suggesting these ewes had utilised their stored body fat to achieve high milk yields. Ewes that decreased BCS between lambing and weaning produced greater (P<0.05) TLW compared with ewes which maintained or gained BCS indicating their body reserves were acting as a buffer for milk production. The results of the current study showed that there was an effect of BCS on NLS, NLW, WWT and TLW. The change in BCS from scanning to weaning is an important determinate of NLW, WWT and TLW. A further study with more focus on the change in BCS is, therefore, warranted.},
	issn = {1176-5283},
	author = {Tait IM and Kenyon PR and Garrick DJ and Lopez-villalobos N and Pleasants AB and Hickson RE}
}
@article {3672,
	title = {Effect of genetic merit for milk urea on milk production and efficiency of crude protein utilization of grazing cows with contrasting supplement inclusion},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {112-117},
	address = {Palmerston North},
	abstract = {Milk urea (MU) has been proposed as a predictor of nitrogen excreted through urine into the environment. The objective of this study was to evaluate milk production performance and efficiency of crude protein utilization (ECPU) of cows with low and high MU breeding values (MUBV) in grazing conditions with two levels of dietary supplementation inclusion. From July 2016 to May 2017, 257 cows were milked once daily with low supplementation (LS; 366 kg/cow/lactation) and 210 cows were milked twice daily with high supplementation (HS; 2,091 kg/cow/lactation). Cows within each herd were ranked as low, intermediate, or high for MUBV. The dataset consisted of 2,318 records of milk production collected from monthly herd-tests of both herds; and 853 additional milk samples obtained at early, mid and late lactation to measure MU. The ECPU was calculated as the proportion of protein yield (PY) with respect to crude protein intake (CPI); with CPI derived from feed intake estimates based on energy requirements. Cows with HS had superior milk yield (MY) and milk solids yield (MSY) [MSY= PY + fat yield (FY)] (P<0.001). Feed intake was less in LS (P<0.001) but CPI was superior compared to HS. The ECPU was better in HS (P<0.001) because of higher PY (P<0.001) along with lower CPI (P<0.001). Levels of MU were superior for LS because of higher CPI. Cows with low-MUBV had significantly lower MU along with less total daily excretion of MU during the lactation (P<0.001). Irrespective of supplementary feed level, cows with low-MUBV had less MY (P<0.001). Low-MUBV did not result in improved ECPU for either supplementary feed level: under LS, ECPU was inferior in cows of low-MUBV (P<0.001), and this was explained by reduced PY (P<0.001).},
	issn = {1176-5283},
	author = {CorreaLuna M and Donaghy DJ and Kemp PD and Schutz MM and Lopez-villalobos N}
}
@article {3672,
	title = {Estimates of genetic parameters for lactation curves for milk, fat, protein and somatic cell score in New Zealand dairy goats},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {1-7},
	address = {Palmerston North},
	abstract = {There are limited data on the average nitrogen (N) intake and N loss for the different classes of equine livestock, and the different equine production systems within New Zealand.  Using a deterministic model, the total nitrogen excreted, and nitrogen partitioned into animal requirements, urine and faeces were estimated based on the crude protein requirement, digestible crude protein intake, and crude protein excreted in urine and faeces.  Separate models were generated for five different livestock classes managed within three different production systems (commercial breeding farm, sport horse and racehorse). Overall, the N in diet (\%), the modelled daily N intake and N losses varied with the percentage of pasture in the diet.  The faecal N loss remained consistent (20-25\%) across diets and horse classes whereas urinary N loss increased with daily N intake and percentage of pasture in the diet. Total N loss per day was estimated to be 0.18, 0.28, and 0.48 g N/kg body weight in racehorse, sport horse and Thoroughbred mares respectively.  The N excretion per unit weight from young horses, racehorses and sport horses were substantially lower than that reported for ruminants. Therefore, horse-specific data should be used when modelling farm-level nitrogen excretion.},
	issn = {1176-5283},
	author = {Scholtens MR and Lopez-villalobos N and Garrick DJ and Blair HT and Lehnert K and Snell RG}
}
@article {3672,
	title = {Estimation of heritabilities for milk urea and efficiency of crude protein utilization by day of lactation in a New Zealand dairy cow herd},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {183-187},
	address = {Palmerston North},
	abstract = {The objective of this study was to estimate the heritability (h2) of milk urea (MU) and the efficiency of crude protein utilization (ECPU) in grazing dairy cows. Data consisted of 1,866 herd-test records for MU and ECPU from 380 cows. Genetic parameters for traits were estimated using a random regression test-day model (RRM). Herd-test date and parity had a significant effect on MU and ECPU suggesting that improvement of the traits can be made through management practices. Estimates of daily h2 ranged from 0.25 to 0.49 for MU and 0.02 to 0.41 for ECPU. The highest h2 estimates for both traits were found during late lactation. Genetic improvement of MU and ECPU should consider the genetic potential to change the lactation curves of these traits and their correlation with other productive and reproductive traits. },
	issn = {1176-5283},
	author = {Ariyarathne HBPC and CorreaLuna M and Blair HT and Garrick DJ and Lopez-villalobos N}
}
@article {3672,
	title = {Growth and milk production of dairy heifers born to two-year-old or mixed-age dams},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {135-139},
	address = {Palmerston North},
	abstract = {Keeping replacement heifers that were the progeny of primiparous cows mated by artificial insemination, enhances rates of genetic gain. Heifers that were the progeny of primiparous cows were lighter at birth and grew at a slower rate to first calving compared with heifers born to multiparous dams. Heifers that were heavier before first calving produced more milk than did lighter heifers. This study aimed to determine if there were liveweight (LWT) or milk-production disadvantages for heifers born from primiparous compared with multiparous dams. Data comprised of LWT records from 189,936 New Zealand dairy heifers. Dams were allocated to four groups according to their age: two (2yo; n=13,717), three (3yo; n=39,258), four to eight (4-8yo; n=120,859) and nine years old or greater (>=9yo; n=16,102). Heifers born to 2yo dams were lighter (P<0.01) from three to 21 months of age than heifers born to 3yo and 4-8yo dams. The progeny of 2yo and 3yo dams produced similar milksolids yields during their first lactation (304.9{\textpm}1.6 and 304.1{\textpm}1.5 kg, respectively), but more (P<0.01) than that of 4-8yo dams (302.4{\textpm}1.5) and >=9yo dams (P<0.001; 297.8{\textpm}1.6 kg). Heifers born to 2yo dams were lighter but produced more milk than heifers from older dams.},
	issn = {1176-5283},
	author = {Handcock RC and Lopez-villalobos N and Back PJ and Hickson RE and McNaughton LR}
}
@article {3672,
	title = {Milk production and rebreeding performance of mixed-aged dairy cows mated to Angus or Hereford bulls},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {144-148},
	address = {Palmerston North},
	abstract = {Approximately 72\% of New Zealand dairy cows are artificially mated to generate replacement heifers. There is an opportunity to mate the remaining dairy cows to beef bulls, generating a calf that has value as a beef-cross-dairy animal. Angus and Hereford are the predominant beef breeds in New Zealand, with Hereford the most common beef breed used in the dairy industry. The aim of this experiment was to determine whether there was a difference in milk production and rebreeding performance of mixed-aged dairy cows producing a calf sired by an Angus or Hereford bull, and if calf birth weight influenced these parameters. Cows were artificially bred to Angus or Hereford bulls. Service sire-breed had no effect on milk production in early lactation. Cows producing Angus-sired calves had a 2.4 kg greater 253-day protein yield (P<0.05) than did cows producing Hereford-sired calves, however, there was no effect of calf sire-breed on the 253-day yields of milk, fat and milksolids. The in-calf rate and inter-calving interval did not differ between service sire-breed. There was no effect of calf birth weight on milk production, in-calf rate or inter-calving interval. The results of this experiment suggest that there are no negative effects associated with artificially breeding cows to Angus compared to Hereford bulls. },
	issn = {1176-5283},
	author = {Coleman LW and Back PJ and Blair HT and Lopez-villalobos N and Hickson RE}
}
@article {3672,
	title = {Regression of traits-other-than-production phenotypes for cows milked once a day on estimated breeding values obtained from cows milked twice a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {79},
	year = {2019},
	month = {07/2019},
	pages = {140-143},
	address = {Palmerston North},
	abstract = {The use of traits other than production (TOP) to aid selection for conformation fit-for-purpose offspring becomes more important as once-a-day (OAD) milking for whole or part season becomes more common. In 2013 Massey University Dairy 1 farm transitioned their mixed-breed herd milked twice a day (TAD) to an OAD spring-calving system. All cows on the farm were scored for 14 inspector TOP traits and four farmer-scored traits for a total of 1,163 records over five seasons (168 to 254 cows per year). The scores were adjusted for age of the cow and season. The adjusted phenotypes for all cows for each trait were then regressed on their corresponding nationally-produced TAD estimated breeding values (EBV), which had been calculated without using these phenotypes. The four farmer-scored traits had the lowest relationships with EBV. Estimates of regression coefficients near one were observed for the udder traits (udder support, rear udder, front teats, udder overall), dairy conformation and body capacity. This supports the use of national EBVs in OAD herds derived mostly from records on daughters in TAD herds. },
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-villalobos N and Garrick DJ and Rocha JF and Donaghy DJ}
}
@article {3672,
	title = {BRIEF COMMUNICATION: Differential expression of lactoferrin and insulin-like growth factor-1 genes in milk from cows milked once and twice a day},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {109-110},
	address = {Lincoln},
	abstract = {Dairy farming in New Zealand has traditionally utilized a twice a day (TAD) milking system, but milking once a day (OAD) for the
entire lactation is also practiced by a significant proportion of dairy farmers. This study reports on the differential gene expression
in milk from OAD and TAD cows. Three predominant dairy breed group of New Zealand, Holstein-Friesian (F), Jersey (J) and F{\texttimes}J
crossbred (F{\texttimes}J) were included in samples collected from both milking regimens. RNA was extracted from milk from 45 OAD and
42 TAD dairy cows during early lactation, and used to determine lactoferrin (LF) and insulin-like growth factor-1 (IGF-1) gene
expression using qPCR. Compared to TAD cows, cows milked OAD had higher expression of the LF gene (1.38 vs 1.30 folds,
P=0.08) and the IGF-1 gene (1.65 vs 1.48 folds, P=0.09). These results suggest that milking frequency affects the expression of
milk composition genes at early lactation.},
	issn = {1176-5283},
	author = {Gedye K and Notcovich S and CorreaLuna M and Ariyarathne P and Heiser A and Lopez-villalobos N}
}
@article {3672,
	title = {Economic value of productive life of cows on organic dairy farms in the United States},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {128-131},
	address = {Lincoln},
	abstract = {Organic milk production is an important sector of the US dairy industry. Productive life, defined as the time that a cow remains in
the herd after first calving, is a trait of economic importance in organic dairy farming affecting the age structure of the herd and
replacement costs. Productive life is of economic importance for inclusion in breeding objectives for organic milk production,
which determine its value for selection. The objective of this study was to estimate the economic value (EV) of productive life
for cows on certified organic dairy farms in the US using a farm-simulation model. Annual net farm income (NFI) per cow was
calculated as gross income minus production costs. Income was derived from the sale of milk, disposed animals and other income.
Milk income was calculated as US$ 0.809/kg milk. Cost of organic feed was US$ 0.308/kg DM. The average productive life of
the herd was 1,302 d with an annual replacement rate of 22.1\%. The herd NFI was US$ 520.70/cow and the EV for productive life
was US$ 1.24/d. This value is higher than the EV of productive life included in the Net Merit (US$ 0.69/d) or Grazing Merit (US$
0.43/d) indexes used for conventional US dairy cattle.},
	issn = {1176-5283},
	author = {Lopez-villalobos N and Schinckel AP and Schultz MM}
}
@article {3672,
	title = {Genetic parameters for milk urea concentration and milk traits in New Zealand grazing dairy cattle},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {56-61},
	address = {Lincoln},
	abstract = {The aim of this study was to estimate genetic parameters for milk urea (MU), yields of milk (MY), fat (FY), crude protein (CPY)
and lactose (LY), concentrations of fat (FP), crude protein (CPP) and lactose (LP) and efficiency of crude protein utilisation
(ECPU) in grazing dairy cows. Data consisted of 1284 herd-test records of milk traits and MU from 468 mixed-breed cows
in two herds. Univariate and bivariate repeatability animal models were used to estimate heritabilities (h2) and genetic (rG) and
phenotypic (rP) correlations among the traits. Estimates of h2 for MU and ECPU were 0.24 and 0.11, whereas h2 estimates for
MY, FY, CPY and LY ranged from 0.10 to 0.20. Estimates of h2 for FP, CPP and LP were 0.37, 0.59 and 0.19, respectively. The
estimates of rP for MU with other traits were near zero. The rG of MU with MY (0.38), and of MU with LY (0.31) were positive and
significant (P<0.01) whereas the rG of MU with FP (-0.80), CPP (-0.66) and LP (-0.76) were negative and significant (P<0.01). The
rG between MU and ECPU was -0.09. These estimates of genetic parameters can be used to predict genetic responses to selection
for reduction of MU.},
	issn = {1176-5283},
	author = {Lopez-villalobos N and CorreaLuna M and Burke JL and Sneddon NW and Schultz MM and Donaghy DJ and Kemp PD}
}
@article {3672,
	title = {Heritability of longevity in New Zealand dairy goats},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {11-15},
	address = {Lincoln},
	abstract = {Longevity is a trait of economic importance in dairy goat farming. Actual longevity (AL) is defined as the number of days from
birth to when the animal leaves the herd, whereas functional longevity (FL) is defined as AL adjusted for first lactation energycorrected
milk yield (ECMY). This study reports the heritability (h2) for AL and FL in New Zealand dairy goats. Records of
longevity from 12,108 does born between 1993 and 2011 were analysed with a model that included the fixed effects of herdyear
(does born in the same herd and year) and covariates for the proportion of Alpine, Nubian, Toggenburg and heterosis, and
the random effect of animal. The model for FL was the same as AL, but included ECMY as a covariate. Average AL was 1,891
(SD=832) days. Estimates of h2 were 0.07 for AL and FL. The estimated regression coefficient for ECMY on AL was 0.56 days/
litre. There were significant differences in longevity among herds, indicating that management and feeding are important factors
affecting longevity. Further research is required to estimate genetic correlations with economically important traits.},
	issn = {1176-5283},
	author = {Scholtens MR and Lopez-villalobos N and Garrick DJ and Blair HT}
}
@article {3672,
	title = {Phenotypic correlations of milk urea and the efficiency of crude protein utilization with milk yield traits and cow performance in two contrasting dairy systems in New Zealand},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {76-81},
	address = {Lincoln},
	abstract = {The objectives of the present study were to investigate phenotypic correlations of milk urea (MU) and efficiency of crude protein
utilization (ECPU) with milk production and cow parameters in two contrasting herds. Between July 2016 and May 2017, 210
cows were milked twice daily with high supplementary feed inclusion (HS) and 258 cows were milked once daily with low
supplementary feed inclusion (LS). In early, mid and late lactation, milk samples were collected to measure MU. At every herdtest
date, ECPU was calculated as protein yield (PY) divided by crude protein intake (CPI); this last variable derived from intake
estimations of metabolizable energy requirements. Positive correlations between milk yield (MY) and both dry matter intake
(DMI) and CPI were observed in LS and HS. The ECPU only correlated positively with MY traits in LS, and there was no
correlation of CPI with MU in either herd. A moderate negative correlation of ECPU with live weight (LW) was observed in both
herds, but it was stronger in LS. By suppressing MY due to the reduced milking frequency of cows fed LS, these cows gained LW,
had higher body condition score and CPI, and lower PY, reducing the ECPU. No correlation between ECPU and MU was detected.},
	issn = {1176-5283},
	author = {CorreaLuna M and Lopez-villalobos N and AlmeidaJr GA and Donaghy DJ and Kemp PD}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: Assessing the current value of milk, meat and fibre products from the goat industry in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {173-176},
	address = {Rotorua},
	abstract = {Goats have a historical record of being productive and valuable to families and communities (Aziz 2010). Small ruminants, which include goats, still have an {\textquoteleft}unfulfilled{\textquoteright} potential despite the numbers of animals farmed and their distribution around the world (Anaeto et al. 2010). Pollot and Wilson (2009) concluded that goats deserve greater attention due to their capacity for producing food. A similar study in New Zealand (Sheppard \& O{\textquoteright}Donnell 1979), described the uses of goats for meat, skins, milk and mohair and concluded that the goat was valuable, but that the production potential was largely unfulfilled. A recent New Zealand study (Ministry of Agriculture and Forestry 2009) concluded that food-consumption patterns are changing in New Zealand, and globally demand for more diversified products provided an opportunity for goat meat. The objective of this study was to determine the current value of domestic and exported New Zealand goat products and to explore possible future products and their target markets. Many of these product values are gathered from retailers, personal communications and individual producers. This research is an attempt to bring together information that has not yet been gathered to present a current value of the goat in New Zealand...},
	issn = {1176-5283},
	author = {Lopez-Lozano SR and Scholtens MR and Smith RMC and Lopez-Villalobos N and Burt D and Harper L and Thomas DG and Carr AJ and Gray DI and Tozer P and Schreurs NM}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: Efficiency of crude protein utilization and milk urea nitrogen content in Friesian, Jersey and crossbred cows milked once daily},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {91-92},
	address = {Rotorua},
	abstract = {For the last two decades, the New Zealand dairy industry has intensified its milk production through the inclusion of feed supplements and the increasing use of nitrogen (N) fertilizer (Di \& Cameron 2000). Increasing N losses from these systems, mainly from urine (Li et al. 2012), can negatively impact the environment. Cow N utilization efficiency can play a role in mitigating this negative effect (Woodward et al. 2011)...},
	issn = {1176-5283},
	author = {CorreaLuna M and Lopez-Villalobos N and Donaghy DJ and Kemp PD and AlmeidaJr GA}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: Once-a-day milking with supplemented cows in Argentina},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {61-63},
	address = {Rotorua},
	abstract = {Dairy farming is an important activity in Argentina. The country produced over 11,000 million litres of milk in 2015 (Ministerio de Agroindustria 2015). Milk production is based on the utilisation of grazed lucerne pastures (Medicago sativa L), and the use of supplements such as silage, hay and concentrate feeds. Pasture comprises between 30\% and 50\% of the diet. Average milk production per cow is 5,900 kg/cow per year (equivalent to 401.2 kg of milk solids/cow per year; INTA 2015). Due to a favourable ratio between milk price and concentrate feeds price (average ratio milk to concentrate price over 1.5), dairy farmers in Argentina include great amounts of concentrate feeds in their systems. Over 95\% of dairy herds of Argentina are Holstein, and cows are milked twice a day (TAD) (FAO 2011).

In the last decade, studies have been conducted, mainly in New Zealand, but also in Europe, to evaluate the effects of once-a-day (OAD) milking during the whole lactation (Stelwagen et al., 2013). Lifestyle benefits for farmers and employees and improvement in animal health and reproductive performance are the main motivations to choose OAD milking (Bewsell et al., 2008)...},
	issn = {1176-5283},
	author = {Lazzarini B and Peluffo L and Lopez-Villalobos N and Hendrikse L and Baudracco J}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: The current state of the New Zealand goat industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {164-168},
	address = {Rotorua},
	abstract = {<p>Goat farming in New Zealand has a lower profile compared to dairy, sheep and beef systems. The goat industry is small in New Zealand (Stafford \& Prosser, 2016) and there has been limited consideration of the potential for the industry to expand (Shepard \& O{\textquoteright}Donnell, 1979). The environmental and commodity market constraints currently impacting pastoral systems in New Zealand provide an opportunity for the goat industry to have a greater economic contribution to New Zealand{\textquoteright}s agricultural production. </p><p>
In New Zealand, goats are farmed for milk, meat and fibre production and also act as a mechanism for controlling excess pasture growth, enhancing clover in mixed pasture and controlling weeds (Batten, 2014). The aim of this paper was to present an overview of the goat industry to provide background knowledge for consideration when deciding the direction of the goat industries in New Zealand. As part of the overview, farmers, processors and industry bodies were contacted to obtain an estimate of the number and location of goats farmed in New Zealand. Although some of the sources of information for the goat industry are not perfect, this research is an attempt to bring together information that has not been consolidated in nearly 40 years (Shepard \& O{\textquoteright}Donnell, 1979) and was achieved as part of a three-part study with companion papers being produced (Lopez-Lozano et al. 2017; Smith et al. 2017). Information from this study were used in conjunction with the value of the goat industry (Lopez-Lozano et al. 2017) to project the potential of the New Zealand goat industry (Smith et al. 2017).</p>},
	issn = {1176-5283},
	author = {Scholtens MR and Smith RMC and Lopez-Lozano SR and Lopez-Villalobos N and Burt D and Harper L and Tuohy M and Thomas DG and Carr AJ and Gray DI and Tozer P and Schreurs NM}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: The potential of the New Zealand goat industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {169-172},
	address = {Rotorua},
	abstract = {The New Zealand goat industry is evolving and there is potential for expansion of its export products. The production and value of the New Zealand goat industry has been explored previously when the industry was in its infancy (Sheppard \& O{\textquoteright}Donnell 1979), at a time when Mohair production was seen to be {\textquoteleft}the most profitable goat farming enterprise{\textquoteright}. Since then major expansion has occurred in the production and export of dairy-goat products, and the production of quality Boer goat meat is under consideration. In order for further progress to be made, knowledge of the current production levels and value of the goat industry, and its potential for expansion is required. Using information describing the current situation of the goat industry (Scholtens et al. 2017) and the value of the goat (Lopez-Lozano et al. 2017), a model was created to estimate the current and potential production and value of the New Zealand goat industry by 2025. },
	issn = {1176-5283},
	author = {Smith RMC and Scholtens MR and Lopez-Lozano SR and Lopez-Villalobos N and Burt D and Harper L and Thomas D and Carr A and Gray D and Tozer P and Schreurs NM}
}
@conference {3672,
	title = {Comparison of health and reproductive treatments over three seasons for once-a-day and twice-a-day milking herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {211-215},
	address = {Rotorua},
	abstract = {Once-a-day (OAD) milking has been increasing in popularity in New Zealand, while housing cows is being advocated as one means of minimising environmental impacts of dairying. The present study aimed to investigate health treatments under four different farming systems: OAD, and three twice-a-day (TAD) systems (housed, standard and commercial). There were health records from 377 cows milked OAD and 878 cows milked TAD, over the dairy seasons 2013-14, 2014-15 and 2015-16. Data were analysed assuming binomial distributions for the dependent variables with a generalised linear model that included the effects of season, system (OAD, TAD systems), breed and lactation number. In 2014-15, cows milked OAD were treated less often for mas-titis than cows milked TAD (12\% and 25\% respectively; P<0.05). Cows milked OAD had fewer reproductive treatments compared to cows milked TAD (standard) in 2014-15 and 2015-16 (1\% vs 39\% and 2\% vs 40\% respectively; P<0.01). These results support the advice to farmers that milking OAD does not have a major impact on the risk of mastitis but may provide benefits in terms of reproductive performance. In addition, cows milked TAD (housed) had 13\% of the cows treated for lameness compared to 7\% of cows milked TAD (standard) (P<0.01). },
	issn = {1176-5283},
	author = {Van Der Spek P and Sneddon NW and Lopez-Villalobos N and Donaghy DJ and Laven RA and Mueller KR and Amoore J and Doohan H}
}
@conference {3672,
	title = {Culling reasons in once-a-day milking cows and differences in production and type traits between retained and culled cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {200-204},
	address = {Rotorua},
	abstract = {The aim of this study was to investigate the culling reasons in cows milked once-a-day (OAD), evaluating the differences of production, fertility and traits other than production (TOP) between retained and culled cows. Cows in different lactations from Massey University Dairy 1 were scored for 18 TOP for three consecutive seasons from 2013 to 2015. Herd-test records were used to estimate milk yield (MY), fat yield (FY), protein yield (PY) and somatic cell score (SCS). Low fertility, poor udder conforma-tion and low production were the main reasons for culling in all seasons. Overall, culled cows had a lower MY (3534{\textpm}56 kg), FY (173.5{\textpm}2.8 kg), PY (138.5{\textpm}2.1 kg) and higher SCS (6.41{\textpm}0.09) than retained cows (MY = 4006{\textpm}41 kg; FY = 204.7{\textpm}1.9 kg; PY = 160.6{\textpm}1.5; SCS = 6.19{\textpm}0.06). Culled cows had a poorer adaptability to milking (7.02 {\textpm} 0.04) and poorer farmer{\textquoteright}s overall opin-ion (7.62{\textpm}0.06) than retained cows (7.23{\textpm}0.03 and 7.89{\textpm}0.04, respectively). Moreover, culled cows had a weaker udder support (5.56), weaker front udder (5.48) and lower rear udder (6.01) than retained cows (6.19, 5.85 and 6.25, respectively). These traits might have a higher influence on the culling decisions of OAD dairy farms than the age and production worth of cows.},
	issn = {1176-5283},
	author = {Rocha JF and Lopez-Villalobos N and Burke JL}
}
@conference {3672,
	title = {Estimates of genetic parameters for direct and maternal genetic effects on weaning weights in Dairymeade sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {129-132},
	address = {Rotorua},
	abstract = {Dairymeade is a newly registered breed of dairy sheep in the emerging New Zealand dairy sheep industry. The objective of this study was to estimate heritabilities and genetic correlations for direct and maternal genetic effects on weaning weight, as this trait reflects the genetic ability of the lamb to grow (direct genetic effect), and the genetic ability of the ewe to feed her lambs (maternal genetic effect) and protect them (maternal permanent environment).  Records of weaning weight were used from 717 lambs born between 2013 and 2016, with a pedigree of 5091 animals over 11 generations. Average and standard deviation of weaning weight, age at weaning and litter size were 18.1{\textpm}4.0 kg, 51.5{\textpm}13.0 days and 2.16{\textpm}0.7 lambs, respectively. At weaning, ewe lambs were 1.1 kg (SE=0.2 kg, P<0.05) lighter than ram lambs and singleton lambs were 4.1 kg (SE=2.9 kg, P<0.05) heavier than triplet lambs. Estimates of heritability ({\textpm}SE) were 0.55 ({\textpm}0.24), 0.24 ({\textpm}0.17) and 0.28 ({\textpm}0.13) for direct, maternal and total genetic effects, respectively. The proportion of total variance explained by maternal permanent environmental influences was 0.14 ({\textpm}0.07). The estimated genetic correlation between direct and maternal genetic effects was -0.72 ({\textpm}0.20). Maternal breeding values can be used to select ewe lambs specifically for milk production.},
	issn = {1176-5283},
	author = {Lopez-Villalobos N and King M and King J and Morris RS}
}
@conference {3672,
	title = {Growth curves of New Zealand Holstein-Friesian, Jersey and Holstein-Friesian-Jersey crossbred heifers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {64-68},
	address = {Rotorua},
	abstract = {There are differences in the proportion of target live weight (LWT) achieved between the main breeds of dairy heifers in New Zealand, suggesting a potential difference in growth pattern. The objectives of this study were to model growth curves of dairy heifers through random regression of Legendre polynomials, and to compare growth curves of the main breeds. Data comprised of 1,653,214 LWT records obtained from 189,936 dairy heifers in 1,547 herds. The fourth-order Legendre polynomial was the best at predicting LWT, with a relative prediction error (RPE) of less than 4\% for the whole dataset and for Holstein-Friesian, Jersey and Holstein-Friesian-Jersey crossbred (F{\texttimes}J) heifers. The regression coefficients of the growth curve differed among breeds for the intercept (α0; P<0.001), linear effect (α1; P<0.001), quadratic effect (α2; P<0.001), cubic effect (α3; P<0.001) and quartic effect (α4; P<0.001). At all ages Holstein-Friesian heifers were heavier than F{\texttimes}J which were heavier than Jersey heifers (P<0.001). The percentage difference among the breeds varied throughout the growth curve, indicating that the main breeds of dairy heifers in New Zealand exhibited different growth patterns that were non-linear. The different growth patterns for each breed should be considered when formulating target LWTs and growth rates.},
	issn = {1176-5283},
	author = {Handcock RC and Lopez-Villalobos N and McNaughton LR and Edwards GR and Hickson RE}
}
@conference {3672,
	title = {The percentage of spring-calving carryover cows in New Zealand dairy herds and their milk production, compared to heifers, age-matched and lactation-matched non-carryover cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {3-7},
	address = {Rotorua},
	abstract = {Non-pregnant cows are generally culled from dairy herds and replaced with heifers. Alternatively, non-pregnant cows can be dried-off at the end of lactation, retained for one year (carried over), before being mated and returned to a milking herd in the following year. The aim of this study was to estimate the percentage of spring-calving carryover cows in New Zealand dairy herds and to compare their milk production with that of heifers, lactation-matched and age-matched non-carryover cows. Results showed that 2.5\% of spring-calving cows had experienced a previous carryover period. The majority (43\%) of carryover cows had failed to conceive during their first lactation. Most (69\%) dairy herds contained less than 5\% carryover cows and 17\% had zero carryover cows. Second-lactation carryover cows produced 4778.1{\textpm}6.3 L milk, 228.7{\textpm}0.3 kg fat, 182.0{\textpm}0.2 kg protein, and had a somatic cell score (SCS) of 6.31{\textpm}0.01, which was greater (P<0.001) than the milk production of heifers that produced 3514.5{\textpm}5.9 L milk, 168.3{\textpm}0.3 kg fat, 134.0{\textpm}0.2 kg protein, and had a SCS of 5.89{\textpm}0.01. Carryover cow milk production was also greater (P<0.001) than that of lactation-matched and age-matched non-carryover groups. The results of this study will aid on-farm culling decisions.},
	issn = {1176-5283},
	author = {Gardner RR and Back PJ and Lopez-Villalobos N and McNaughton LR}
}
@conference {3672,
	title = {Prototype genetic evaluation in a New Zealand dairy sheep flock},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {121-124},
	address = {Rotorua},
	abstract = {Dairy sheep milking is an emerging industry in New Zealand, but at present there is no national breeding scheme. A prototype model for the genetic evaluation of dairy sheep was developed. Data were obtained from a flock of 123 crossbred ewes, over 479 monthly flock tests during the season 2015/16.  Breeding values were estimated for lactation yields of milk, fat, protein and lac-tose, and for live weight, somatic cell score, first let-down time and yield, and number of lambs born, from a multiple-trait animal model. Heritabilities and phenotypic and genetic correlations required for the model were obtained from the literature, and pheno-typic standard deviations were obtained from the data set. This prototype model to obtain estimated breeding values of animals in this flock can be extended to other dairy sheep farmers, to create selection schemes at industry level and start a systematic breeding program for the emerging New Zealand dairy sheep industry.},
	issn = {1176-5283},
	author = {Scholtens MR and Peterson SW and Gunson K and Gunson A and Lopez-Villalobos N}
}
@conference {3672,
	title = {Random regression curves for body condition score and live weight from cows in two different dairy systems over three seasons},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {77},
	year = {2017},
	month = {06/2017},
	pages = {72-76},
	address = {Rotorua},
	abstract = {As housing is adopted to minimise the environmental impacts of farming activities in New Zealand, it becomes important to investigate the impact of this on the body condition of cows as a predictor of animal welfare. The P21 project undertaken at Massey University{\textquoteright}s Dairy 4 recorded the body condition score (BCS) and live weight (LW) of cows either under duration-controlled grazing during sensitive periods ({\textquoteleft}housed{\textquoteright}) or standard feed-pad ({\textquoteleft}standard{\textquoteright}) system. A total of 10,350 BCS records and 10,950 LW records were available from 978 cows over three dairy seasons (2013-14 to 2015-16). Random regression curves for daily BCS and LW were modelled using a 5th order Legendre polynomial. Data were analysed with a linear model, which included the effects of system, season, the system by season interaction and proportion of breeds (Jersey and Friesian), and cow age fitted as co-variants. The BCS was greater in 2014-15 than in either 2013-14 or 2015-16, (4.48 vs 4.33 and 4.28, respectively). The BCS of the housed and standard cows were significantly different (P <0.01) in 2013-14 and 2015-16. Housed cows were heavier than standard cows in both 2013-14 and 2014-15. These results indicate that housing of cows could improve on their BCS and LW. },
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Donaghy DJ}
}
@conference {3672,
	title = {Estimation of genetic parameters for milk yield traits at different herd production levels in cows milked once- or twice-daily in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {76},
	year = {2016},
	month = {07/2016},
	pages = {49-53},
	address = {Adelaide},
	abstract = {The objective of this study was to estimate genetic parameters for lactation yields of milk (MY), fat (FY) and protein (PY) for cows
milked either once- (OAD) or twice-a-day (TAD) at different production levels (PL), calculated as average milk solids yield (FY
+ PY) for dairy cattle in New Zealand. Lactation records of 124,620 and 194,631 cows from 298 and 350 herds milked OAD and
TAD, respectively were used. Heritiabilities (h2) were lower in low PL herds milked OAD compared to low PL herds milked TAD
(0.11-0.18 vs. 0.22-0.37). Across PL, h2 for MY at medium and high PL were greater than 0.30 at both MF, while for FY and PY,
those values were less than 0.30. Genetic correlations (rG) between MY and PY were greater (>0.70) compared to rG between FY
and any of the other traits (<0.65). The lowest rG was observed between MY and FY at low PL (0.09{\textpm}0.087). In conclusion, lower
h2 at low PL from cows milked OAD reveal unequal genetic expression of milk traits genes compared to higher PL. Ignoring the
heterogeneity of variance in the genetic evaluation could result in systematic inaccuracies and biases in the estimation of breeding
values for cows milked OAD.},
	issn = {1176-5283},
	author = {Lembeye F and Lopez-Villalobos N and Burke JL and Davis SR}
}
@conference {3672,
	title = {Genetics of alternative definitions of feed efficiency in grazing lactating dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {76},
	year = {2016},
	month = {07/2016},
	pages = {38-42},
	address = {Adelaide},
	abstract = {There has been anecdotal evidence of increasing liver abscessation on bull-beef farms across New Zealand from meat processors
for more than a decade, but to date, no quantitative data has been published in the field. This study objective was to establish the
incidence of liver abscessation in pasture- based beef bulls, the seasonality and breed differences, the impact on carcass weight,
and to compare this with published data from feedlot cattle internationally. The study used a database of 137675 bulls slaughtered
in the South Island between 2000-2005. The database included breed, farm location, carcass weight, liver abscess presence and
abscess grading score (absent, mild, moderate, severe). The annual incidence of liver abscessation calculated was a mean of 9.5\%.
This recorded value is greater than other observed incidences from pasture-based systems and reduced compared with those observed
in non-medicated feedlot systems internationally. There were significant variations in all measured parameters across years,
and a clear and significant seasonal variation was observed. Incidence of liver abscessation peaked across November- December
(11.3 and 11\% respectively) and then declined as the slaughter season progressed. The typical NZ beef industry approach to rearing
bulls for slaughter makes it likely that age at slaughter is a key influence on the seasonal incidence rate, with most cattle born in
spring and slaughtered after 18 months, suggesting the late spring and summer peak in incidence is due to bulls older than two
years. The percentages of abscesses graded were: severe (66.4\%), moderate (12.8\%), and mild (20.7\%). Friesian and dairy crossbreed
bulls had an incidence approximately twofold greater than that females beef breeds (10.3\% and 4.7\% respectively). There
was a significant difference in the mean carcass weights of bulls graded, with those moderate with abscessation having a mean
heavier carcass weight than those graded severe, minor and no abscess.},
	issn = {1176-5283},
	author = {Hurley AM and Lopez-Villalobos N and McParland S and Lewis E and Kennedy E and O{\textquoteright}Donovan M and Burke JL and Berry DP}
}
@conference {3672,
	title = {Supply curves for yields of dairy products from first-lactation Holstein Friesian, Jersey and Holstein Friesian-Jersey crossbred cows accounting for seasonality of milk composition and production.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {76},
	year = {2016},
	month = {07/2016},
	pages = {139-143},
	address = {Adelaide},
	abstract = {The economic efficiency of a milk-processing system is influenced by seasonality of the milk supply, and changes to milk
composition, influences the product potential of that milk. Lactation curves for milk yield and composition for seasonal calving
first-lactation Holstein Friesian (F), Jersey (J) and Holstein Friesian-Jersey crossbred (FxJ) cows were used as inputs in a
deterministic simulation model to produce seasonal curves for daily yields of dairy products. The dairy products were whole milk
powder, skim milk powder, cheese, or butter. Dairy product potential was estimated for each animal from a population of 4333
mixed-breed, first-lactation cows. Lactation lengths differed (P<0.0001), among F, FxJ, and J, which averaged 219, 222 and 221
days respectively. Total-lactation milk yield was different (P<0.0001) among breeds and averaged 3257, 3092 and 2902 litres for
F, FxJ and J cows, respectively. Whole-milk powder potential (yield per 1000 L of milk) was greatest at the start of the season
and least at the end of the season, whereas cheese-production potential (yield per 1000 L of milk) followed the opposite pattern.
Total-lactation whole-milk powder yield was different among breeds (P<0.0001) at 366, 338 and 312 kg of whole-milk powder for
F, FxJ and J cows, respectively. Total-lactation cheese yield was also different among breeds (P<0.0001), and was 371, 375 and
361 kg for F, FxJ and J cows, respectively. The supply curves indicate that milk is best processed into whole or skim milk powder
during peak season, and cheese and butter at the end of lactation. However, seasonal production of specific products would limit
the use of by-product lactose from cheese manufacture in the production of milk powders, and thus negate the efficiency gains
from changes to processing priorities.},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Davis SR and Hickson RE and Shalloo L and Garrick DJ}
}
@conference {3672,
	title = {BRIEF COMMUNICATION: Composition of milk sampled from beef-cross-dairy cows unaccustomed to milking.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {260-262},
	address = {Dunedin},
	abstract = { },
	issn = {1176-5283},
	author = {Hickson RE and Back PJ and Coleman LW and Lopez-Villalobos N and Kenyon PR and Morris ST}
}
@conference {3672,
	title = {Estimation of a premium for milk with a high concentration of unsaturated fatty acids based on farm and processor profit: A simulation study.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {54-59},
	address = {Dunedin},
	abstract = { The objective of this study was to determine, via simulation, the premium required for dairy farmers supplying milk with a high
concentration of unsaturated fatty acids (UFA) to a dairy processor to equal the operating profit ($/ha) of average farms, under
New Zealand conditions. Fifty average farms (AVE farms) and fifty farms that fed an oilseed supplement to dairy cows (UFA
farms) were simulated. The processing of milk produced by AVE farms and UFA farms into skim-milk powder and butter was also
simulated. The physical and financial characteristics of dairy farms and a dairy processor were investigated under two scenarios:
1) no premium for UFA and 2) a premium for UFA which equalled the operating profit ($/ha) of UFA farms to that of AVE farms.
UFA farms were not different from AVE farms in yields of milk, milkfat and protein, but their farm expenses were greater (P<0.05)
than for AVE farms. A premium of $0.15/kg milkfat (for each 0.1 g UFA/100 g milkfat increase) was necessary for UFA farms
to have an operating profit ($/ha) similar to AVE farms. These results may be used to further evaluate the impact of modifying
milkfat UFA concentration at the farm level.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Hickson RE and Blair H and MacGibbon A}
}
@conference {3672,
	title = {Estimation of breed and heterosis effects for milk traits and somatic cell scores in cows milked once and twice daily in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {60-63},
	address = {Dunedin},
	abstract = { Crossbreeding is widely used by famers milking twice-a-day (TAD) to increase farm profitability. Effects of crossbreeding on farm
productivity and profitability have not been investigated in farms practicing once-a-day (OAD) milking. The aim of the study was
to estimate breed and heterosis effects for lactation length (LL), total yields of milk (MY), fat (FY) and protein (PY) and average
somatic cell score (SCS) in cows milked OAD or TAD. Records from 36,276 Friesian (F), 31,560 Jersey (J) and 90,081 crossbred
(F{\texttimes}J) cows that calved in spring between 2008 and 2012 were used. Compared to J cows, F cows had a higher MY (657 kg in
OAD and 1034 kg in TAD), FY (2.9 kg in OAD and 7.8 kg in TAD), PY (13.6 kg in OAD and 22.4 kg in TAD) and SCS (0.28
in OAD and 0.05 TAD). Lactation length in OAD cows was five days shorter than in TAD cows (P<0.05). These results show
a significant interaction between breed and milking frequency for production traits (P<0.001). Expressed as a percentage of the
average of parental breeds, first-cross heterosis effects ranged between 4.92 to 6.84\% for production traits, and were similar across
milking frequencies. The estimates of breed and heterosis obtained in this study can be used for simulation studies to evaluate the
profitability of crossbreeding systems under OAD and TAD milking systems of typical New Zealand dairy farms.},
	issn = {1176-5283},
	author = {Lembeye F and Lopez-Villalobos N and Burke JL and Davis SR}
}
@conference {3672,
	title = {Estimation of crossbreeding effects on yields of dairy products and value of milk processed in different product portfo},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {48-53},
	address = {Dunedin},
	abstract = { The international market requires milk products to meet specified minimum standards that define acceptable composition. This
study used a deterministic simulation model to estimate milk products yields of individual cows for different export markets. Four
milk product portfolios were analysed which included 100\% of the milk to either whole-milk powder (WMP), skim-milk powder,
cheese, or butter. Milk product potential was estimated for 4310 mixed-breed heifers from LIC Sire Proving Scheme herds based
on total lactation production. Lactation lengths were 212, 214 and 213 days for Holstein Friesian (HF), Holstein Friesian-Jersey
crossbreds (HFxJ), and Jerseys (J) respectively. Milk yields were significantly different between breeds averaging 3121 for HF,
2947 for HFxJ, and 2751 litres for J cows. Holstein Friesians had the lowest fat, protein and lactose concentrations, whereas J had
the highest. Holstein Friesian had the greatest yields of WMP per 1000 litres of milk, whereas J had the least. For all scenarios, J
milk was most valuable per litre. Crossbred cows provided greater total milk income for all scenarios except 100\% butter. Positive
heterosis effects were estimated for first-cross HFxJ animals for milk production and product yields. Crossbreeding produces cows
with milk better suited to the processing requirements of the New Zealand dairy industry and returning greater value to the New
Zealand dairy farmer.},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Hickson RE and Shalloo L and Garrick DJ}
}
@conference {3672,
	title = {Phenotypic correlations among alternative definitions of feed efficiency in grazing lactating dairy cows across parities and lactation stages},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {34-38},
	address = {Dunedin},
	abstract = { The objective of this study was to estimate correlations among alternative measures of energy conversion efficiency and energy
balance (EB) across parities and lactation stages in grazing lactating dairy cows. Individual measurements of net energy intake
(NEI) (n=8,183) from pasture and concentrate from 2,693 lactations on 1,412 cows were available. Residual energy production
(REP) was defined as net energy of lactation (NEL) minus predicted energy requirements; energy conversion efficiency (ECE)
was defined as NEL divided by NEI; and EB was defined as the difference between NEI and energy required for both maintenance
and lactation. Residual energy intake (REI) was defined as NEI minus predicted energy requirements. A strong correlation existed
between REI and EB (0.88; P<0.05) for parity three or greater early lactation, weakening in parity one (0.70; P<0.05). These
differences in correlations between REI and EB for animals across parities in early lactation, indicated primiparous animals were
using body energy for milk production and growth; nevertheless, these strong correlations suggested negative REI animals (i.e.,
more efficient) are also in more-negative EB. Our findings suggest REI could be a valuable tool for future genetic improvement,},
	issn = {1176-5283},
	author = {Hurley AM and Lopez-Villalobos N and McParland S and Lewis E and Kennedy E and O{\textquoteright}Donovan M and Burke JL and Berry DP}
}
@conference {3672,
	title = {Stayability of beef-cross-dairy breeding cows to six years of age},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {75},
	year = {2015},
	month = {07/2015},
	pages = {159-163},
	address = {Dunedin},
	abstract = { The use of dairy-beef crosses is widespread throughout the New Zealand beef industry. Cattle originating from dairy herds make
up 50 {\textendash} 55\% of New Zealand beef exports by weight (Morris \& Kenyon 2014). However, there is little information available
regarding the use of beef-cross-dairy cows as breeding cows in terms of reproductive success and stayability in the herd. A study
was conducted to investigate the pattern of cow culling and stayability from eight months of age until marking of the fifth calf of
straight-bred Angus and Angus-cross-Friesian, Angus-cross-Jersey and Angus-cross-Kiwicross cows. The results showed that the
stayability of these breeding cows was low, however, there were no differences in the stayability of straight-bred Angus or beefcross-
dairy cows.},
	issn = {1176-5283},
	author = {Hickson RE and Corner-Thomas RA and Martin NP and Kenyon PR and Lopez-Villalobos N and Morris ST}
}
@conference {3678,
	title = {BRIEF COMMUNICATION: Genetic evaluation for milking performance in a large flock of milking sheep in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {55-57},
	address = {Napier},
	issn = {1176-5283},
	author = {McMillan WH and McLachlan SJ and Hercus IS and Lopez-Villalobos N}
}
@conference {3678,
	title = {BRIEF COMMUNICATION: High milk production in milked sheep grazed in large flocks in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {52-54},
	address = {Napier},
	abstract = {<p>There is a paucity of published information in New Zealand (NZ) sheep on milk production in commercial-scale dairy enterprises. Much of the early research involved small numbers of animals focused on traditional breeds, with the Dorset breed considered the most suitable dairy-type sheep (e.g., Geenty \&amp; Jagusch 1974). Importation of East Friesian sheep in the mid-1990s provided new opportunities for sheep dairying (Allison 1996). Since that time, there appears to be a limited number of papers published in NZ on the milking performance of animals of East Friesian origin (e.g., Newman \&amp; Steiffel 1999; Peterson et al. 2005)...</p>
},
	issn = {1176-5283},
	author = {McMillan WH and McLachlan SJ and Hercus IS and Lopez-Villalobos N}
}
@conference {3678,
	title = {BRIEF COMMUNICATION: Milk production, live weight, body condition and somatic cell score during the first 150 days of lactation in Friesian, Jersey and crossbred cows milked once daily},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {46-48},
	address = {Napier},
	abstract = {Pasture-based dairy farming in New Zealand has predominately been with cows milked twice a day (TAD). However, since the last decades, milking once a day (OAD) has been adopted by some farmers in New Zealand for herd management and lifestyle benefits (Davis 2005)...},
	issn = {1176-5283},
	author = {Lambeye F and Lopez-Villalobos N and Burke JL and Davis SR}
}
@conference {3678,
	title = {Supply and demand for lactose in the New Zealand dairy industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {215-219},
	address = {Napier},
	abstract = {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.},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Hickson RE and Shalloo L and Garrick DJ and Geary U}
}
@conference {89259,
	title = {Does Production Worth and Breeding Worth reflect cow profitability?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {17-20},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>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{\textquoteright}s or sire{\textquoteright}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 \&lt;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 \&lt;0.001). This study confirms that PW, rather than BW, better reflects the genetic capability of a cow to convert feed into farm profit.</p>
},
	issn = {1176-5283},
	author = {Clark BJ and Garcia-Muniz JG and Black PJ and Lopez-Villalobos N}
}
@conference {89265,
	title = {Effect of dam size and nutrition during pregnancy on fetal testicular development in sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {41-44},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>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\&nbsp; 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).</p>
},
	issn = {1176-5283},
	author = {Asmad K and Kenyon PR and Parkinson TJ and Pain SJ and Lopez-Villalobos N and Blair HT}
}
@conference {89258,
	title = {Efficiency of beef breeding cows that vary in live weight and milking potential},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {11-16},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>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 {\textpm} 3 kg and 224 {\textpm} 4 kg respectively. These calves were heavier than those weaned by AJcows (212 {\textpm} 3 kg). All of these three genotypes weaned heavier calves than AA cows (197 {\textpm} 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 {\textpm} 0.7\%. AJ and AK cows were the most efficient at 46.7 {\textpm} 0.7\% and 46.0 {\textpm} 1.0\%, respectively. AJ cows were also more efficient than the AF cows (44.0 {\textpm} 0.8\%). Increased milking potential and decreased live weight of breeding cows increased their efficiency of production.</p>
},
	issn = {1176-5283},
	author = {Law NL and Hickson RE and Lopez-Villalobos N and Kenyon PR and Morris ST}
}
@conference {89250,
	title = {Mastitis pathogens isolated from dairy cattle that were managed on conventionally or organically maintained matched farmlets},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {183-185},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>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 \&amp; 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\&nbsp; Strep.</p>
},
	issn = {1176-5283},
	author = {Ullah Z and Margerison JK and Simcock DC and Thatcher A and Lopez-Villalobos N}
}
@conference {89263,
	title = {Review of milk payment systems to identify the component value of lactose},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {33-36},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>New Zealand{\textquoteright}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 {\textquoteleft}A+B-C{\textquoteright} 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 {\textquoteleft}F+P+L-V{\textquoteright} 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 {\textquoteleft}F+P+L-V{\textquoteright} payment system results in smaller deviation from the true value of the milk for differing breeds, milk compositions and product mixes than the current {\textquoteleft}A+B-C{\textquoteright} system of milk payment.</p>
},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Hickson RE and Shalloo L}
}
@conference {89233,
	title = {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},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {108-113},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>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.</p>
},
	issn = {1176-5283},
	author = {Garcia-Muniz JG and Lopez-Villalobos N and Burken JL and Sandbrok T and Vazquez-Pelaez CG}
}
@conference {79011,
	title = {Economic values for New Zealand dairy goats},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {166-168},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {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.},
	issn = {1176-5283},
	author = {Solis-ramirez J and Lopez-Villalobos N and Blair HT}
}
@conference {78985,
	title = {Effects of maternal nutrition during pregnancy on the growth and reproductive development of male sheep: a meta-analysis},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {51-57},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {<p><span style="color: rgb(102, 102, 102); font-family: ARIAL;">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.</span></p>
},
	issn = {1176-5283},
	author = {Asmad K and Nakagawa S and Lopez-Villalobos N and Kenyon PR and Pain SJ and Blair HT}
}
@conference {78975,
	title = {Examination of New Zealand sport horse performance records and their suitability for the calculation of breeding values},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {3-7},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {<p>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.</p>},
	issn = {1176-5283},
	author = {Creagh FE and Lopez-Villalobos N and Hickson RE and CW Rogers}
}
@conference {78991,
	title = {Genetic parameters for lactose and its relationship with concentrations and ratios of other milk components},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {76-80},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {<p>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 {\textpm} 0.12 (standard error) for MY, 0.25 {\textpm} 0.10 for FY, 0.30 {\textpm} 0.12 for PY, 0.27 {\textpm} 0.11 for MSY, 0.50 {\textpm} 0.12 for LY, 0.24 {\textpm} 0.04 for P:F ratio and 0.53 {\textpm} 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.</p>
},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Hickson RE and Shalloo L}
}
@conference {79014,
	title = {Productivity and financial characteristics of herds that produce milkfat with different concentration of unsaturated fatty acids using a stochastic farm model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {175-180},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {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.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Blair HT and Hickson RE and MacGibbon AKH}
}
@conference {79003,
	title = {Validation of a bio-economic dairy production model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {139-143},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {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.},
	issn = {1176-5283},
	author = {Visser A and Lopez-Villalobos N and Morel PCH}
}
@conference {75910,
	title = {The apparent digestibility of palm kernel expeller (PKE) consumed by pasture-fed sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {223-228},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {<p>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.</p>
},
	issn = {1176-5283},
	author = {Burke JL and Dias FN and Pacheco D and Lopez-Villalobos N and Holmes CW}
}
@conference {75880,
	title = {Dairy goat production systems in Waikato, New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {86-91},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {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 {\textpm} standard deviation per doe and per hectare were 2.8 {\textpm} 0.2 and 34.0 {\textpm} 3.7 kg respectively; while milk-solids were 0.32 {\textpm} 0.02 kg/doe and 4.10 {\textpm} 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.},
	issn = {1176-5283},
	author = {Solis-ramirez J and Lopez-Villalobos N and Blair HT}
}
@conference {75905,
	title = {Effect of lactation stage and breed on the concentration of unsaturated fatty acids in milkfat of New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {203-207},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {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.},
	issn = {1176-5283},
	author = {Silva-Villacorta D and Lopez-Villalobos N and Blair HT and Hickson RE and Spelman RJ and Melis J and Davis SR and Berry SDK and Lehnert K and Snell RG}
}
@conference {75866,
	title = {Effect of pre-grazing herbage mass on grazing behaviour, grass dry matter intake and milk production of dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {28-32},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {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.},
	issn = {1176-5283},
	author = {Tu{\~n}on G and Lopez-Villalobos N and Kemp PD and Kennedy E and Hennessy D and O{\textquoteright}donovan M}
}
@conference {75908,
	title = {Efficiency, cheese yield and carbon emissions of Holstein-Friesian, Jersey and crossbred cows: an overview},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {214-218},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {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.},
	issn = {1176-5283},
	author = {Sneddon NW and Lopez-Villalobos N and Baudracco J}
}
@conference {75888,
	title = {Genetic analysis of incidence of recorded clinical lameness in New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {71},
	year = {2011},
	month = {Jan},
	pages = {126-130},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Invercargill},
	abstract = {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 {\textpm} 0.003 (standard error) while the repeatability was 0.071 {\textpm} 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.},
	issn = {1176-5283},
	author = {Chawala AR and Lopez-Villalobos N and Margerison JK and Spelman RJ}
}
@conference {69532,
	title = {Blood metabolic profiles in Uruguayan Holstein and Uruguan Holstein x New Zealand Holstein-Friesian dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {311-315},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {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.},
	issn = {1176-5283},
	author = {Periera I and Laborde D and Lopez-Villalobos N and Ruprechter G and Carriquiry M and Meikle A}
}
@conference {69514,
	title = {Genetic analysis of incidence of clinical mastitis in New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {246-249},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The aim of the study was to estimate breed and geneticeffects on the incidence of clinical mastitis (CM) in New Zealand dairy cattle. Records of CM collected during seasons 2005-06 to 2008-09 from 53,419 cows of different breeds including Holstein-Friesian (H-F), Jersey (J) and Crossbed (HF x J), were analysed. Clinical mastitis was coded {\textquotedblleft}1{\textquotedblright} for cows that presented at least one event of CM at any day at risk during the season and {\textquotedblleft}0{\textquotedblright} for cows without CM. Genetic parameters and breed effects for the incidence of CM were estimated with a repeatability animal model across breeds using restricted maximum likelihood methodology. The cumulative lactation incidence of CM was 11\% in92,961 lactations. Heritability and repeatability for incidence of CM were 0.015 {\textpm} 0.003 and 0.070 {\textpm} 0.005, respectively. Jersey cowshad 2.9\% less incidence of CM than H-F cows. Heterosis effect of H-F x J was minus 11.7\% of the average of the parental breeds. Results from this study confirm previous estimates ofgenetic parameters for CM. Sire variation and breed and heterosis effects were significant and can be exploited in a breeding program to improve resistance to CM in New Zealand dairy cattle.},
	issn = {1176-5283},
	author = {Jury K and Lopez-Villalobos N and Spelman RJ and Arias J and Heuer C}
}
@conference {69464,
	title = {Phenotypic relationship between milk protein percentage and reproductive performance in three strains of Holstein Fresain cows in Ireland},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {29-32},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The relationship between milk protein percentage and fertility in seasonal calving, dairy cattle in Ireland was quantified using a total of 584 lactation records, collected over a five-year period from experiments comparing three strains of Holstein-Friesian cows under three different feeding systems. Logistic regression analyses showed that increased protein percentage during early lactation was positively associated with the probability of a cow becoming pregnant to its first service (P <0.05). Similarly, protein percentage during the lactation had a positive (P <0.01) association with overall pregnancy rate. The results suggest that negative energy balance in early lactation or during the whole lactation causes a shortage of glucose to the udder, this restricts the synthesis of milk protein in the udder and causes a lower milk protein percentage. During negative energy balance there is also a concurrent reduction of IGF-І, LH and oestradiol secretion, which consequently delay ovarian follicular development, and hence impairs reproductive performance. In conclusion, cows with higher milk protein percentage during early lactation have a greater likelihood of becoming pregnant earlier in the breeding season, and have a higher conception rate.},
	issn = {1176-5283},
	author = {Yang L and Lopez-Villalobos N and Berry DP and Parkinson T}
}
@conference {69468,
	title = {Potential benefits of low replacement rate for dairy herd production and profit},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {46-50},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The effects of different replacement rates on the genetic gain for lactation yields of milk and milksolids (fat + protein) per cow and farm profit per hectare were evaluated using a simulation model. Three levels of replacement rate were simulated 15, 19 and 27\%, by varying the levels of involuntary culling, such as with low fertility, and voluntary culling based on production worth. The effect of selection of replacements based on breeding worth was also evaluated. In the base year, farm profit was higher for lower replacement rates. Annual genetic gain in average herd breeding values for milksolids after 20 years of using bulls of high breeding worth was higher at higher replacement rates. However, farm profit at Year 20 was still higher for a herd with a low replacement rate than for a herd with a high replacement rate. A herd with a 15\% replacement rate in combination with selection of replacement heifers based on breeding worth, achieved the highest gain in breeding values for milksolids and achieved the highest farm profit at Year 20. These results demonstrate that low replacement rate in combination with selection of high breeding worth heifers can achieve high genetic gain in both milksolids and farm profit.},
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Holmes CW}
}
@conference {69476,
	title = {Prediction of herbage dry matter intake for dairy cows grazing ryegrass-based pastures},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {80-85},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {A model that combines theoretical and empirical equations was developed to predict daily dry matter intake (DMI) for Holstein-Friesian (HF) cows grazing ryegrass-based swards and offered differing levels of concentrate supplementation. An upper limit to potential herbage dry matter (DM) intake at grazing was set, which is the lower of three limits set by either physical (rumen fill), metabolic (energy demand) or grazing restrictions. Potential herbage DMI at grazing and the herbage allowance were then used to predict herbage DMI, of cows fed only pasture, using an empirical algorithm. If supplements are fed, substitution rate was predicted to calculate actual herbage DMI. An independent dataset, with individual herbage DMI measurements (n = 1,147) of three strains of lactating HF cows, was used to validate the model. Data within strains were averaged for every month of lactation, allowing 27 data points for validation. The fitness of the model was satisfactory, with a relative prediction error (RPE) of 0.083 and a concordance correlation coefficient (CCC) of 0.74. Herbage DMI was simulated for HF cows of different genotypes fed different levels of concentrate supplementation at different herbage allowances. The model successfully predicted herbage DMI of grazing cows under different combinations of nutritional, physiological and genetic variables.},
	issn = {1176-5283},
	author = {Baudracco J and Lopez-Villalobos N and Holmes CW and MacDonald KA}
}
@conference {69531,
	title = {Productive and reproductive performance of Uruguayan Holstein and Urugyayan Holstein x New Zealand Holstein Friesian cows in a predominantly pasture-based system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {306-310},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The performance of Uruguayan Holstein (UH) and UH x New Zealand Holstein Friesian first cross (UHNZHF) cows was investigated over 1 year using 62 cows offered predominantly native pasture. Accumulated 305 day yields of milk, fat, protein and milksolids (fat+protein) were not affected by the strain. The UH cows produced 0.5 L/d more milk than UH-NZHF cows at Day 240 of lactation (P <0.05). Fat and lactose percentages were greater in UH-NZHF cows (3.72 vs 3.44\% and 5.02 vs 4.94\%, respectively, P <0.0001). Protein percentages tended to be greater in UH-NZHF cows (3.31 vs 3.27\%, P = 0.08). The UH cows were 49 kg heavier (569 vs 520 kg, P <0.001) and required a greater energy requirement for maintenance. The UHNZHF cows produced more milksolids per kg of BW0.75, (P <0.01). Pregnancy rates tended to be greater in UH-NZHF cows (87 \% vs 71\%, P = 0.08) and were greater when the first 40 days of service were considered (61 vs 35\%, P = 0.04), which may be related to a differential energy partitioning according to strains.},
	issn = {1176-5283},
	author = {Periera I and Laborde D and Carriquiry M and Lopez-Villalobos N and Meikle A}
}
@conference {60943,
	title = {Breed effects for lactoferrin concentration determined by Fourier transform infrared spectroscopy},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {60-64},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A calibration equation based on partial least squares using Fourier transform infrared spectroscopy (FTIR) data was derived to predict concentration of lactoferrin (Lf) in bovine milk. The concordance correlation coefficient of the calibration equation was estimated at 0.81 using 246 milk samples collected in the 2003-04 season from second-parity crossbred cows during late lactation. The calibration equation was then used to predict the concentration of Lf (pLf) in 9,742 milk samples from 814 Holstein-Friesian (HF), 955 Jersey (J) and 842 crossbred HF x J cows sampled on average 3.7 times during the 2007-08 season. A repeatability animal model was used to obtain breed effects and estimates of variance components for pLf. Concentrations of pLF (mg/L milk) were significantly (P <0.001) different between breed groups (HF = 163 {\textpm} 3.8, HF x J = 175 {\textpm} 5.0 and J = 193 {\textpm} 6.3). Heritability and repeatability of pLf concentration were 0.16 {\textpm} 0.036 and 0.35 {\textpm} 0.012, respectively. These results confirm previous studies showing that Lf concentration in milk can be predicted using FTIR spectroscopy and that there are significant breed differences and animal variation that can be exploited in a breeding program. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Davis SR and Beattie EM and Melis J and Berry S and Holroyd SE and Spelman RJ and Snell RG}
}
@conference {60940,
	title = {Factors associated with frequency of lameness in dairy cattle managed in pasture based systems with the addition of supplementary feeds : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {51-53},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Lameness is one of the main welfare problems of New Zealand dairy herds (Chesterton et al., 2008) and contributes directly to cow culling, treatment costs, production losses and reduced economic efficiency (Kossaibati \& Esslemont, 1997). The incidence of lameness can be high, affecting as many as 60\% (Vermunt, 2004) of cows annually, but can vary from between 5 and 55\% (Clarkson et al., 1996) according to differing observation techniques and... Continued},
	issn = {1176-5283},
	author = {Diaz-Lira CM and Margerison JK and Lopez-Villalobos N and Gibbs SJ}
}
@conference {60977,
	title = {Genetic parameters for somatic cell score in dairy goats estimated by random regression},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {206-209},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of the study was to estimate genetic parameters of somatic cell score (SCS = log2 of somatic cell count / 1000) in New Zealand mixed-breed dairy goats using a random regression model. The dataset comprised 37,051 herd-test records of somatic cell counts (SCC) from 3,688 does kidding between 2000 and 2007 distributed in 47 herds. The mixed model included the fixed effects of contemporary group (herd-year-month of kidding), lactation number (1st, 2nd and 3rd), and the covariables day-of-month, proportion of Saanen, Nubian, Alpine and Toggenburg breeds, heterosis, and a second-order orthogonal polynomial of days in milk across all data and for each lactation number. The random effects included a second order random regression polynomial for the additive animal effect and the doe permanent environmental effect within parity and doe permanent environmental effect across parities. The residual variance was assumed heterogeneous, with different residual variances for each of the nine months of lactation. Estimates of heritability increased from 0.12 to 0.25 from the beginning to the end of the lactation and estimates of repeatability ranged from 0.46 to 0.59, also increasing from the beginning to the end of lactation. These results show that genetic improvement can be achieved in SCC by including SCS in selection index. },
	issn = {1176-5283},
	author = {Apodaca-Sarabia CA and Lopez-Villalobos N and Blair HT and Prosser CG}
}
@conference {42049,
	title = {Effect of genotype and concentrate supplementation on dairy product mix and the value of milk produced by grazing dairy cows during an extended lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {79-83},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Dairy product mix and milk value were investigated in Holstein-Friesian cows of New Zealand or overseas origin that grazed pasture and were supplemented with 0, 3 or 6 kg DM concentrate/cow/day during a 600-day extended lactation. A dairy product supply chain model was used to predict relative changes in dairy product mix and milk value during the "extended period" (300 to 600 days in milk) compared with the "normal period" (0 to 300 days in milk). Cow genotype and level of concentrate supplement affected dairy product yields, with little consistency of effect between "normal" and "extended" periods. Milk produced during the "extended period" resulted in more cheese, butter, butter milk powder, casein, and whey protein concentrate, but less whole milk powder, skim milk powder and whey milk powder compared to the "normal period". The overseas strain and those cows receiving higher levels of concentrates had less of a decline in whole milk powder yields associated with the "extended period". Milk value ($/L), was predicted to be 20.8\% higher during the "extended period" compared with the "normal period". These results indicate that extended lactations may improve the dairy product mix and milk value following processing. },
	issn = {1176-5283},
	author = {Turner S-A and Phyn CVC and Kolver ES and Aspin PW and Lopez-Villalobos N}
}
@conference {42051,
	title = {Genetics of residual energy intake in Irish grazing dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {88-91},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {The objective of this study was to investigate the genetics of residual net energy intake (RNEI) in grazing Holstein-Friesian cows. RNEI was defined as net energy intake minus predicted net energy requirements using the unit{\'e} fourrag{\`e}re lait (UFL) system. Net energy intake from grass and concentrate was estimated up to four times per lactation on 1,111 lactations from 463 cows on an experimental farm in Southern Ireland. Grass dry matter intake was estimated using the n-alkane technique. Lactation curves for milk, fat, protein, lactose and live weight were modelled with splines using weekly measures. A random regression was used to estimate residual, additive genetic and permanent environmental variances for RNEI and breeding values at Day 60 for each cow. Heritability for RNEI across lactation varied from 0.05 at 30 days in milk to 0.38 at 296 days in milk. Genetic parameters for RNEI obtained in this study are in agreement with those obtained under indoor conditions. Comparative performance between cows of low and high RNEI breeding value at Day 60 agrees with results obtained in beef cattle selected for high or low residual feed intake showing similar productivity but higher feed conversion efficiency in cows selected for low residual feed intake.},
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Berry DP and Horan B and Buckley F and Kennedy J and O{\textquoteright}Donovan M and Shalloo L and Dillon P}
}
@conference {41764,
	title = {Breed and heterosis effects for milk protein composition estimated in two stages of lactation in New Zealand dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {399-402},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The aim of this study was to estimate breed and heterosis effects for milk protein composition found within the two main breeds farmed in New Zealand, Holstein-Friesian (HF) and Jersey (J). Groups of 20 F, 20 J and 20 HFxJ crossbred cows (3 years and older) calved at pasture between July and September 2003 and were monitored throughout the 2003/04 season. Breed and heterosis effects were estimated for daily yields of milk, crude protein, true protein and casein and concentrations of crude protein, true protein, casein, α-casein,  β-casein,  κ-casein,  α-lactalbumin and  β-lactoglobulin, bovine serum albumin (BSA) and immunoglobulin G (IgG). Breed effects were significant (P<0.05) for all traits except for β-lactoglobulin, BSA and IgG. Compared to J cows, HF cows had significantly (P<0.05) higher daily yields of milk (+5.32 kg), crude protein (+0.13 kg), true protein (+0.11 kg) and casein (+0.10 kg) but significantly (P<0.05) lower concentrations of crude protein (-0.50 g/kg), true protein (-0.51 g/kg), casein (-0.45 g/kg), α-casein (-3.77 g/kg), β-casein (-2.08 g/kg), κ-casein (-1.74 g/kg) and α-lactalbumin (-0.14 g/kg). Estimates of heterosis effects for concentration of milk proteins were negative but only significant for κ-casein (-0.60 g/kg). These results show that that the individual protein fractions of milk are affected by breed but crossbreeding has no beneficial effect on milk protein composition.},
	issn = {1176-5283},
	author = {Back PJ and Lopez-Villalobos N}
}
@conference {41729,
	title = {Choice of the most appropriate models and estimation procedures of lactation curves for grazing dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {209-214},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The objective of this study was to determine the most appropriate lactation curve representation, a 4th order Legendre polynomial (LP) function or a mechanistic mammary gland (MG) model, for various lactation curve shapes of grazing cattle in New  Zealand. The ability of two optimisation methods, evolutionary algorithm (EA) and the Newton method, used to find parameter values that minimised mean prediction error (MPE) was also determined. The 95\% confidence intervals for the parameters values and goodness of fitness for each lactation function and numerical algorithm were obtained with a bootstrapping strategy. Milk yields of three different cows were chosen to describe bi-peak, highly variable, and springpeak lactation curves. The MG function was able to find the best fit between predicted and actual values for the bi-peak and highly variable lactation curves withMPE of 2.7 to 3.7\%, compared with MPE of 6.5 to 11.9\% for the LP function applying Newton and EA. For the traditional lactation curve, the LP function applying Newton had the lowest MPE (1.7\%) with the MG function applying an EA the highest MPE (4.1\%). Overall, minimal differences in MPE were observed when solving using the Newton and EA. However, the Newton method fixed some parameters values of the MG function to achieve approximately the same MPE as the EA which manipulated all parameter values. The results of this study illustrate that a MG function solved with an EA is an accurate and efficient way to model non-standard lactation curves but a LP function in combination with the Newton method canbe better option for more standard lactation curves},
	issn = {1176-5283},
	author = {Bryant JR and Lopez-Villalobos N}
}
@conference {41993,
	title = {Effect of age on methane emissions of red deer stags from weaning until one year of age grazing perennial ryegrass-based pasture : Brief Communication},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {276-279},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The emission of greenhouse gases is a current global issue as global warming and climate change appear a reality. The Kyoto Protocol is an international agreement, which New Zealand (NZ) has signed and under obligations of the agreement, New Zealand must reduce its greenhouse gases (GHG) to the emission levels of the baseline year (1990), by the first ratification of the Protocol in 2008. Methane emissions from ruminant livestock in NZ represent 31.3\% of New Zealand{\textquoteright}s total greenhouse gas emissions; therefore accurate inventories of methane production for all farmed livestock classes are required.},
	issn = {1176-5283},
	author = {Swainson NM and Hoskin SO and Clark H and Lopez-Villalobos N}
}
@conference {41700,
	title = {The effect of Finnish Landrace and Texel ewe and lamb behaviour after tagging on lamb survival to weaning},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {48-54},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The study was carried out on a commercial New Zealand sheep farm with performance recorded 
straightbred Finnish Landrace and Texel primiparous ewes. The objective of the study was to determine the 
strength of ewe-lamb attachment at tagging by investigating the behaviour of Finn and Texel ewes and their 
lambs and relate those behaviours to survival to weaning. Lamb and ewe behaviour was observed for ten 
minutes after the lambs were ear tagged. Finn ewes took at least twice as long to contact their lambs than 
Texel ewes (P<0.01). There were no breed differences for time of lamb to stand and suck after tagging. Finn 
twin lambs took longer to follow their dam than Texel twin lambs (P<0.01). Ewes with higher Maternal 
Behaviour Score (high MBS favourable) contact their lambs quicker and the lamb stood, sucked and 
followed its moving dam more quickly than lambs of ewes with low MBS (P<0.05). Texel ewes with twins 
had higher low-pitch bleating frequencies than Texel ewes with a single lamb (P<0.01). MBS had a 
significant and positive effect on low-pitch bleating frequency (β=19.3 {\textpm} 3.51 bleats/MBS, P<0.0001). Ewes 
with lower MBS at tagging high-pitch bleated significantly more if their lamb took longer to stand (β=5.25 {\textpm} 
0.65 bleats/minute, P<0.0001). Lamb survival improved3-fold for lambs that sucked their dam (P<0.01) and 
improved nearly 5-fold for lambs that stand, within ten minutes after tagging (P<0.05). Lamb behaviour at 
tagging better explained the variation in lamb survival than the ewe behaviours analysed. },
	issn = {1176-5283},
	author = {Everett-Hincks JM and Blair HT and Stafford KJ and Lopez-Villalobos N}
}
@conference {41711,
	title = {The effect of maternal liveweight gain of 15-month-old beef heifers on foetal weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {117-120},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Dystocia in 2-year-old beef heifers is a major factor limiting the willingness of farmers to breed 15-month-old heifers in New Zealand. Foetal oversize relative to the size of the heifer is a contributor to dystocia. This study aimed to determine the effect on foetal weight of maternal liveweight change during joining and early pregnancy. Sixteen 15-month-old Angus heifers were allocated to moderate (444 {\textpm} 30 g/day) or low (109 {\textpm} 28 g/day) liveweight-gain treatments for 21 days prior to and 91 days after insemination. Gravid uteri were recovered on day 91 of pregnancy. Foetuses from the low-fed heifers tended to be heavier than foetuses from the moderate-fed heifers (215.6 {\textpm} 6.7 g and 198.4 {\textpm} 6.8 g, respectively; P=0.09). Foetal weight per 100 kg maternal weight was greater (P<0.01) in foetuses from the low treatment (58.9 {\textpm} 2.5 g/100 kg) than in foetuses from the moderate treatment (47.4 {\textpm} 2.6 g/100 kg). Weight of foetal membranes was greater (P<0.05) in the low treatment (262 {\textpm} 16 g) than the moderate treatment (213 {\textpm} 16 g). Foetal weight was correlated with cotyledon weight (r=0.59; P<0.05). Moderate compared with low maternal liveweight gain reduced foetal weight relative to maternal live weight.},
	issn = {1176-5283},
	author = {Hickson RE and Lopez-Villalobos N and Kenyon PR and Morris ST}
}
@conference {41965,
	title = {The effects of ewe size and nutrition during pregnancy on growth and onset of puberty in female progeny},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {126-129},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {In 2005, {\textquoteleft}heavy{\textquoteright} and {\textquoteleft}light{\textquoteright} Romney ewes were selected, synchronized and artificially inseminated. Half of the ewes in each weight group were fed ad libitumand the other half were restricted to maintenance from days 21-140 of pregnancy, resulting in fourgroups: {\textquoteleft}heavy{\textquoteright}-maintenance (HM), {\textquoteleft}heavy{\textquoteright}-ad libitum(HA), {\textquoteleft}light{\textquoteright}-maintenance (LM) and {\textquoteleft}light{\textquoteright}-ad libitum(LA). The aim of the present study was to investigate the effects of ewe size and nutrition during pregnancy on growth and onset of puberty in female progeny. Lamb birth weights were recorded. After weaning, the progeny were managed as one flock and weighed monthly. Crayon-harnessed teaser rams were joined with the lambs to investigate the onset of puberty. Maternal nutrition during pregnancy affected live weight of lambs from 22 days of age till weaning (100 days of age) (P<0.05). During the first 22 days of life, the growth rate of lambs born to LM was lower (P<0.05) compared with the other groups (215 {\textpm} 8.2, 261 {\textpm} 8.0, 250 {\textpm} 7.9, 275 {\textpm} 7.3 grams/day, for lambs born to LM, LA, HM and HA ewes respectively). From weaning until one year of age lambs born to LM dams were lighter than lambs born to HM dams (P<0.05). No differences in the age of onset of puberty were found among the four groups. Singletons reached puberty earlier than twins (P<0.01). At 13 months of age, no long-term effect of maternal nutrition on the live weight of resulting ewe offspring was found, although dam size had a significant effect on live weight and growth rate. However, neither dam nutrition nor size had any effect on the age of onset of puberty.},
	issn = {1176-5283},
	author = {van der Linden DS and Kenyon PR and Jenkinson CMC and Peterson SW and Lopez-Villalobos N and Blair HT}
}
@conference {41746,
	title = {Effects of experimentally induced and treated Streptococcus uberis mastitis early in the dry period on production in the subsequent lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {303-306},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The effect of experimentally induced clinical mastitis in the early dry period (EDPCM) upon the milk production in the subsequent lactation was examined. Animals with low somatic cell counts at herd test (n=165) were experimentally exposed to Streptococcus uberis in their early dry period in an efficacy study of two external teat sealants. Animals that developed EDPCM after challenge (n=127) were treated with an antibiotic after observation of clinical mastitis. Total lactation yields of milk, fat, protein and milk solids were analysed with respect to treatment group (fixed effect) and the covariables: calving week (linear), parity (linear and quadratic) and proportion of Holstein-Friesian genes (linear). For animals that suffered EDPCM and those that did not, there was no difference in production (milk yield; 5126 vs. 5010 litres, fat yield; 267 vs. 264 kg, protein yield; 182 vs. 179 kg). It was concluded that promptly treated EDPCM due to S uberis, did not affect production in the subsequent lactation.},
	issn = {1176-5283},
	author = {Petrovski KR and Williamson NB and Fernandez C and Grinberg A and Lopez-Villalobos N and Parkinson TJ}
}
@conference {41611,
	title = {Development of a model to predict pasture intake for grazing dairy cows in Argentina},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {35-41},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {The nutritional value of legumes for high milk production is seldom captured because grazed dairy pastures in NZ typically contain insufficient legume tosatisfy the cows{\textquoteright} requirements. This paper reports interim results from a project investigating novel methods of forage presentation to cows, to enhance the contribution of legume to their diet. Four groups ofspring-calving cows (n=5) in late-lactation were allocated to four treatments in a balanced, cross-over design. Two treatments consisted of spatial and temporal arrangements of grass and white clover allocatedto cows as follows: i) continuous free access to grass and white clover growing separately as side-by-sidemonocultures (G/C) and ii) grass-only at {\textquoteright}night{\textquoteright} between the afternoon and morning milking and clover-only during the {\textquoteright}day{\textquoteright} between morning and afternoon milking (GnCd). These were compared against controlsof iii) a typical mixed ryegrass-white clover pasture (Mix; an industry standard) and iv) a ryegrass-only pasture (Grass; a forage standard). Cows grazed each treatment for 8 days before moving to the next treatment in the pre-determined sequence. Measurements included milk production and composition, the time spent grazing during the day and the night (separately for grass and white clover in G/C) and the concentrations in the milk of skatole and indole, as metabolic indicators of nutrient acquisition and utilisation in the contrasting forage treatments. Cows offered G/C or GnCd produced 19.4 and 17.9 kg milk/cow/day, respectively, compared with 15.0 and 14.6 kg/cow/day when offered Mix or Grass, respectively (P=0.01, SEM=0.74). The diurnal distribution of grazing was influenced by pasture treatment (treatment x  time interaction P <0.001). Cows on G/C grazed proportionately more at {\textquoteleft}night{\textquoteright} and cows on GnCd proportionately less at {\textquoteleft}night{\textquoteright} compared with Grass or Mix. GnCd constrained the cows to spend less time grazing clover than those offered G/C (245 vs. 408 mins grazing clover during 24 hrs) and more time grazing grass (253 vs. 105 mins in 24 hrs). The apparent {\textquoteright}restriction{\textquoteright} in GnCd to grazing clover-only during the day did not significantly reduce milk yield compared with G/C. The spatial and temporal allocations of grass and clover affected the concentrations of indolic compounds in PM and AM milk, suggesting there is scope to improve the efficiency of protein utilisation in the rumen.},
	issn = {1176-5283},
	author = {Baudracco J and Lopez-Villalobos N and Holmes CW and Brookes IM and Kemp P and Comeron E and Romero LA and Horan B and Dillon P and Berry D}
}
@conference {41834,
	title = {The effect of genotype on milk composition, milk value and dairy farm profitability},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {276-282},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {This study was conducted to determine the effect of genotype on milk composition, milk value and economic farm surplus (EFS). The trial included two high breeding worth ($BW) strains of either North American (OS90) or New Zealand (NZ) (NZ90) genetics, and one low $BW strain of NZ genetics (NZ70). Each strain was farmed under systems designed to provide total feed allowances of 4.5 to 7.0 t DM/cow/year. For two years (2001/2002 \& 2002/2003) monthly average milk yield and composition were determined for each of the 11 herds. A simulation model was used to calculate milk value using three product mixes. Using either the simulated values or actual values (paid by Fonterra 2002/2003) for milk and its components, milk value ($/litre and $/kg milksolids (MS)) and an EFS for each herd was determined. The OS90 strain produced milk with lower concentrations of fat and protein and higher protein:fat ratio than NZ70 or NZ90 strains. The effect of strain on milk price was unaffected by product mix. Milk value differed between strains irrespective of method of determination. Milk value expressed as $/kg MS was lowest for the NZ70 and highest (P < 0.001) for the OS90 strain. When expressed as $/litre milk value was highest (P < 0.001) for the NZ90 strain. Milk value expressed as $/kg MS was positively associated with protein:fat ratio whereas milk value expressed as $/litre was positively associated with MS concentration. Average EFS was greater for the NZ90 than the NZ70 strain and was least for the OS90 strain. The factors associated with EFS were MS production; milk value and milk composition had minimal impact. New Zealand{\textquoteright}s dairy cattle breeding programme has produced a strain of Holstein- Friesian with increased milk fat and protein concentration, an increased protein:fat ratio, and an associated increased milk value and increased EFS. In comparison, the OS90 strain which the current $BW index ranks as high as the NZ90, produced milk with higher value ($/kg MS) but resulted in lower EFS.
Key words: milk price; milk value; milk composition; economic farm surplus. },
	issn = {1176-5283},
	author = {Thomson NA and Turner S-A and Glassey CB and Lopez-Villalobos N}
}
@conference {41527,
	title = {The effect of SF6 release rate, animal species and feeding conditions on estimates of methane emissions from ruminants},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {3-8},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {In New Zealand methane (CH4) emissions are estimated using the sulphur hexafluoride (SF6) tracer technique. This involves inserting a calibrated source of SF6 gas into the rumen. The technique does not measure CH4 directly but estimates emissions from the ratio of CH4 to SF6 in breath samples collected continuously from above the nose of each animal. Methane estimates obtained using this method tend to be more variable than measurements obtained using respiration calorimetry. The absolute release rate of SF6 from the rumen could contribute to this variation.
Data were extracted from a database containing details of 22 separate New Zealand experiments where the SF6 technique was used to estimate CH4. Experiments were divided into four groups according to species and feeding situation, with each group analysed separately. Data were analysed using a linear mixed model with a fixed effect of SF6 release rate, and random effect of experiment. In indoor fed cattle and sheep daily CH4 production was positively related to SF6 release rate (P < 0.05) but there was no relationship between SF6 release rate and daily CH4 production in grazing animals. In grazing sheep and cattle there was no significant effect of SF6 release on CH4 emitted per kg DMI. In cattle kept indoors CH4/kg DMI was positively related to permeation tube flow rate (P < 0.05) but there was no significant effect of SF6 release on CH4 emitted per kg DMI in indoor fed sheep.
KEYWORDS: methane; SF6 tracer technique; ruminants. },
	issn = {1176-5283},
	author = {Vlaming JB and Clark H and Lopez-Villalobos N}
}
@conference {41838,
	title = {Estimation of lactation persistency in crossbred grazing dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {300-305},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Lactation persistency is commonly referred to as the rate of decline in daily yield after the peak of lactation and can be measured in different ways. The objective of this study was to calculate different measures of persistency for milk traits and estimate the correlations between parameters of the lactation curve in crossbred cattle. Herd test records of milk, fat, protein and lactose from 810 first lactation cows were used to obtain individual lactation curves using a mixed model fitting six knots splines. The model included the fixed effects of contemporary group (year-calving week), sire, age at calving (linear and quadratic) and an average spline and the random effect of cow-spline interaction. All cows were in their first lactation, second cross Friesian x Jersey from a crossbreeding experiment established for quantitative trait loci identification. Persistency was measured in three different ways: P1, slope of the line fitted using linear regression of daily yield on day of lactation from day 60 to day 220; P2, the area under the lactation curve from day 121 to 180 divided by the area under the curve from day 1 to 60; and P3, the 240-day lactation yield divided by peak yield multiplied by 240. Correlations between measurements of persistency ranged from 0.24 to 0.81 and were significantly different to zero (P < 0.001). Correlations between lactation yield and measurements of persistency ranged from -0.43 to +0.33 and were significantly different to zero (P < 0.01). These results indicate that measurements of persistency are not invariant and highlight the need to calculate persistency in a more consistent way. When cows were classified for persistency P2 of fat plus protein, cows of high persistency (top 25\%), compared with cows of low persistency (bottom 25\%), had significantly (P < 0.05) more days in milk, higher total yields of milk and its components, lower peak yields, later day of peak yield and lower rate of decline in daily yield from day 60 to day 220 (P1), but similar 240-day total yield of fat and protein. Farming cows of high persistency may be an alternative to reduce farm investments in peak notes and risks of metabolic problems and reproductive failures.
KEYWORDS: lactation persistency; milk yield. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Spelman RJ and Harris BL and Stanley G and Harcourt S}
}
@conference {41830,
	title = {Is goat meat acceptable to Japanese youth? The first goat meat taste survey in Japan},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {256-260},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Two sensory evaluations of goat meat were carried out to examine the acceptance of goat meat by Japanese youth. The first test used 172 university students to examine the preference between loin and hind leg of domestic goat. The second test employed 35 university students to rate taste differences between loin and fillet. The sensory analysis between loin and hind leg showed that {\textquoteleft}chewiness{\textquoteright} in goat meat was highly rated. Also loin meat was relatively highly evaluated in comparison with hind leg meat. Fillet meat obtained slightly higher evaluation in comparison with loin meat. Due to the expense of goat meat at retail outlets in Japan, New Zealand could have an advantage of shipping loin and fillet goat meat to meet the future demand by Japanese youth.
KEYWORDS: goat; meat: sensory test; Japan. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41562,
	title = {Milk production in East Friesian-cross ewes lambing year round},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {173-177},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Milk production of groups of East Friesian cross ewes lambing at intervals of 73 days (i.e., five times per year: August (n = 21), November (n = 29), January (n = 13), March (n = 14) and June (n = 14)) was measured on alternate days in the first week post partum and at weekly intervals for nine weeks. Ewes with single and twin lambs were enrolled if they safely delivered the appropriate number of lambs indicated by previous scanning. Ewes and lambs were separated in the morning and ewes milked by machine following i.v. oxytocin (1 i.u.) and stripped by hand until empty. Ewes returned to pasture whilst lambs were housed and bottle-fed. At afternoon milking (after a precisely measured interval of about 6 h) milk yields were recorded. From that yield and the time interval, daily milk yields were calculated. Data were analysed using a mixed linear model for repeated measures. Twin-bearing ewes produced significantly more milk than single-bearing ewes (P < 0.001). Lactogenesis differed significantly (P < 0.001) between the lambing groups. Over the whole lactation, milk yield differed significantly (P < 0.001) between different lambing groups. Milk yields were highest following June lambing (2223 {\textpm} 35 g/day), followed by November (2107 {\textpm} 24 g/d), August (1932 {\textpm} 36 g/day), January (1826 {\textpm} 31 g/day) and March (1742 {\textpm} 30 g/day). A significant lambing group by rearing rank interaction (P < 0.001) indicated that single- and twin-bearing ewes responded differently to seasonal differences; ewes with twins increased milk yield proportionately more than ewes with singles in June, November and January.
KEYWORDS: milk yields; sheep; STAR system. },
	issn = {1176-5283},
	author = {Peterson SW and Kenyon PR and Morris ST and Lopez-Villalobos N and Morel PCH}
}
@conference {41538,
	title = {The productivity of pasture-based dairy farms in New Zealand with different levels of extra feed input},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {63-67},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of this research was to study the physical and financial performance of commercial dairy farms in New Zealand that differed in the amount of extra feed used. Data from Dexcel{\textquoteright}s ProfitWatch corresponding to 626 owner-operated dairy farms between 1998/1999 and 2001/2002 were analysed. The data were classified according to each of the four dairy seasons and the extra feed used per cow. Extra feed comprised supplements imported (hay, pasture silage, maize silage, concentrates and other feeds), winter grazing and maize silage grown on the farm. The statistical analyses were done in SAS and comprised analyses of variance and regression analyses. High feed input farms (H farms, 740-940 kg extra DM /cow/year) had higher stocking rates (2.7-2.8 vs 2.4-2.5 cows/ha), lower comparative stocking rate (83-86 vs 83-92 kg live weight/t DM), and higher milksolids (MS) production per cow (293-341 vs 249-295 kg MS/cow) and per hectare (826-921 vs 616-744 kg/ha) than low feed input farms (L farms, 20 kg DM extra feed/cow/year). The use of nitrogen fertiliser was also higher in the H farms than in L farms (85-116 vs 53-67 kg N/ha/year). There were no significant differences in farm size, herd breeding worth, reproductive characteristics of the herds and estimated pasture consumed per hectare. On average, extra feed was significantly associated with extra cows (0.17 extra cows/ha for 1 t extra DM) and extra milk solids (50 g extra MS/cow for 1 kg extra DM/cow and 96 g extra MS/ha for 1 kg extra DM/ha), but the wide variability is shown by the low values for R2 (0.13 to 0.16 for the three relations above). The H farms produced higher gross farm incomes per hectare (by $0.47 to $0.49/kg extra DM offered) but had higher farm working expenses per hectare (by $0.36 to $0.37/kg extra DM offered), so that Economic Farm Surplus per hectare was not higher for these farms in any year. High management skills and control of costs are necessary for profit to be increased by the use of extra feeds.
KEYWORDS: low-input; high-input; extra feed. },
	issn = {1176-5283},
	author = {Silva-Villacorta D and Holmes CW and Shadbolt NM and Lopez-Villalobos N and Prewer W and Glassey CB and Blackwell M}
}
@conference {41556,
	title = {Relationships between milk yield, milk composition and electrical conductivity in dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {143-147},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The purpose of this study was to investigate the relationships between electrical conductivity (EC) and milk yield and composition in Japanese dairy cattle. In total, 4380 quarters of 106 cows were used in this study. Individual cows were herd tested in the evening with a quarter-milker fortnightly on at least 6 occasions during the lactation. Herd test records were collected from 1990 to 1998. Each quarter was sampled for milk yield, concentrations of fat, protein, lactose and solids-not-fat (SNF) and EC. Each milk quarter sample was classified into one of 9 classes of EC value and one of 10 classes of quarter difference EC value (QdEC). The QdEC for each quarter was calculated as the difference between the EC value for that quarter and the EC value of the quarter with the lowest value within the same cow, on a given herd-test day. Statistical analyses were performed using a mixed linear model for repeated measures considering the fixed effects of quarter position, lactation stage and their interaction, parity, calving season and the EC or QdEC class, and random effects of cow and quarter within cow.
Previous studies have recommended criteria for healthy quarters of < 6.3 mS/cm for EC and < 0.3 mS/cm for QdEC. In the present study, quarters with values above these criteria did have significantly lower milk yields (by 15 to 20\%), but these decreases became apparent above values for EC and QdEC of 5.4 mS/cm and 0.2 mS/cm respectively, much lower than the suggested criteria. Milk yield was reduced by approximately 2\% for every 0.1 mS/cm increase in the QdEC. The higher value classes for EC, and for QdEC both showed significantly lower concentrations of fat, lactose and SNF (P < 0.05). In the present study, decreases in milk yield and concentration of fat and lactose occurred in quarters that would have been considered to be normal by the previously accepted criteria for EC and QdEC.
KEYWORDS: electrical conductivity; milk yield; milk composition. },
	issn = {1176-5283},
	author = {Yoshida T and Lopez-Villalobos N and Holmes CW}
}
@conference {41542,
	title = {An update on beef traceability regulations in Japan},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {80-84},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {An updated beef traceability system has been in operation in Japan since December 2004. This system enables consumers to check the origin of beef products, not only for table meat, but also for restaurant cuisine. The system is dependent on producers, abattoirs, meat wholesalers and meat retailers recording and managing information on each cattle beast using a ten-digit individual identification number. It would not be an exaggeration to say that the essence of the Japanese beef traceability system would not be possible without this individual identification number. Fukaya Wagyu adopted an extended traceability system by presenting detailed information which is missing in the national system. This detailed information enables a {\textquoteleft}face to face{\textquoteright} relationship to be established between the farmer and consumer. This relationship is an effort to promote the supermarket{\textquoteright}s own brand to the customer.
KEYWORDS: traceability system; beef; Japan. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41465,
	title = {Can mating ewes on condensed tannin-containing forages be used to reduce lamb mortality between birth and weaning?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {30-33},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Five grazing experiments are described where ewes were fed forages which are likely to increase the absorption of essential amino acids (EAA) for periods of 63-70 days, immediately before and during mating, relative to control ewes mated on grass based pastures. The legume Lotus corniculatus (Birdsfoot trefoil CV Grassland Goldie) was fed in two experiments and supplements of willow or poplar forage trees were given to ewes mated on low quality drought pasture in three experiments. Both L. corniculatus and the forage trees contained condensed tannins (CT) and in addition the crude protein content of the forage trees (166 g/kg DM) was much higher than that of drought pasture (122 g/kg DM).
Mating on L. corniculatus and supplementing with forage trees consistently increased lambing percentage. Lamb mortality between birth and weaning was significantly reduced (P<0.05) by mating on L. corniculatus in one experiment and by feeding forage trees during mating in one experiment. Similar trends of smaller magnitude were evident in the other experiments and did not attain statistical significance.
Hypotheses of how feeding these forages during mating may have reduced post-natal lamb mortality are advanced and methods of testing the hypotheses are suggested. },
	issn = {1176-5283},
	author = {Barry TN and Parkinson TJ and Ramirez-Restrepo CA and McWilliam EL and Lopez-Villalobos N}
}
@conference {41509,
	title = {The effect of ewe and lamb post-parturient behaviour on lamb survival to weaning: A comparative study of Finns and Texels},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {223-226},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Post parturient behaviours of twinning Finn and Texel ewes and their lambs were monitored under commercial conditions and a relationship sought between this and lamb survival to weaning. Texel lamb survival to weaning was greatest when Texel ewes quickly made contact with their lamb following birth (within 2 minutes) and for lambs that located their dam{\textquoteright}s udder within 30 minutes from birth. Finn lamb survival to weaning was improved when Finn lambs were more vocal after birth, when Finn ewes had higher MBS and when Finn ewes spent a greater proportion of time grooming their lambs. Variation in perinatal behaviour within and across breeds was large and therefore potential exists for improving the ability of the ewe and lamb to bond successfully at parturition by selecting for some of the behaviours identified in this study that encourage lamb survival to weaning. },
	issn = {1176-5283},
	author = {Everett-Hincks JM and Stafford KJ and Blair HT and Lopez-Villalobos N}
}
@conference {41502,
	title = {The effect of ewe nutrition on maternal behaviour score and litter survival},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {188-191},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Mothering ability was investigated in two breeds of sheep with twin and triplet litters in 2000. The study was carried out on a commercial sheep farm with high reproductive rates gained through intensive selection in its Coopworth flock and the introduction of East Friesian genes by crossbreeding.
East Friesian Coopworth (EFCoop) ewes maintained body condition between pregnancy scanning and lambing whereas Coopworth ewes lost body condition (-0.35 CS). Plasma β-hydroxybutyrate (β -OHB) was significantly higher in Coopworth ewes prior to lambing. Coopworth and EFCoop ewes with triplet litters had elevated levels of plasma {\^a}- hydroxybutyrate concentration compared to ewes with twins (0.70 {\textpm} 0.03 vs 0.49 {\textpm} 002, P<0.0001).
Coopworth ewes had higher triplet litter survival rates to tagging (0.86 {\textpm} 0.03) compared with EFCoop ewes (0.68 {\textpm} 0.05) (P<0.001). The maternal behaviour score (MBS) of ewes was determined within 24 hours of birth on the basis of their response to the shepherd tagging their lambs on a 5-point scale from 1 (ewe leaves litter and does not return) to 5 (ewe remains within 1m of her litter). The maternal behaviour score (MBS) was higher in Coopworth ewes (3.6 {\textpm} 0.04) than the EFCoop ewes (3.4 {\textpm} 0.07) and increased with litter size but remained constant for EFCoop ewes regardless of litter size.
The results of this study suggest that ewes that maintain condition in late pregnancy provide a more suitable maternal environment to support their litters. This is increasingly important for triplet litters. This study shows that a ewe that has slightly higher plasma β-hydroxybutyrate levels, is not as receptive to the demands of her litter and is sensitive to human interference as indicated by lower MBS. },
	issn = {1176-5283},
	author = {Everett-Hincks JM and Blair HT and Stafford KJ and Lopez-Villalobos N}
}
@conference {41474,
	title = {The effect on sheep reproduction of grazing willow fodder blocks during drought},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {67-71},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {A trial was conducted in the summer/autumn of 2003 to determine the effect of grazing on willow fodder blocks (6,000 stems/ha) during mating, relative to control ewes grazed on drought pasture, upon ewe production and reproduction. Grazing occurred over 10 weeks, from 19 February including 3 cycles of mating, with ewes randomly assigned to four treatment groups each of 100. The treatments were short drought pasture (typical of drought pasture), long drought pasture (typical of the pasture growing in the willow fodder blocks), short drought pasture with restricted willow access (restricted access) and full access to willow fodder blocks (fenced on the willow all the time; full access). After mating the four groups were joined together and managed as one mob until weaning.
Substantial live weight loss occurred in the short control group (101 g/day), as would occur in severe drought conditions and reproductive rate was low. Ewes in the full access group had significantly (P<0.05) less live weight loss of 40g/day, with reproductive rate increased by approx 20\% units (P<0.05). The increase in reproductive rate in the group with full access to willow fodder blocks was due to increases in fecundity, with more ewes giving birth to twin lambs. Live weight loss during mating in the long control and restricted access groups was intermediate between the short control and full access groups (75-86 g/d) and significantly different from either (P<0.05); reproductive rate was also intermediate between the short control and full access groups but was not significantly different from either (P>0.05). Grazing willow fodder blocks with full access during times of drought can be used to reduce the decline in reproductive rate, which occurs when ewes are mated on drought pastures. },
	issn = {1176-5283},
	author = {Pitta DW and Barry TN and Lopez-Villalobos N and Kemp PD}
}
@conference {41494,
	title = {Effects of a commercial feed containing conjugated linoleic acid on the production of milk components and the value of milk},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {150-154},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {This study was to evaluate changes in cow productivity and milk value from feeding a rumen-protected form of CLA to pasture-fed dairy cows in early lactation. 30 New Zealand Friesian dairy cows were randomly assigned at calving to either 0g (control) or 120g/d of a commercial rumen protected feed containing CLA from 4 days post-calving for 16 weeks. Milk yield and composition data was collected weekly. A simulation model was used to calculate yield of dairy products based on accumulated yields of milk and its components per cow during the experimental period. Feeding CLA reduced (P<0.001) fat concentration (3.1\% vs 4.2\%) and increased (P<0.05) milk yield (2688 kg vs 2423 kg), and protein yield (89.9 kg vs 81.2 kg). The effect of CLA on milk fat concentration was reflected in the yield of dairy products and milk value. Milk from cows fed CLA had less (P<0.01) excess of fat sold as butter (48.4 vs 69.4 kg butter). The value of milk ($/kg MS) was higher (P<0.001) from cows fed CLA than from control cows at 2002/03 prices ($3.87 vs $3.66) and when butter price was low ($3.56 vs $3.24). },
	issn = {1176-5283},
	author = {Back PJ and Lopez-Villalobos N}
}
@conference {41487,
	title = {Mate selection to control inbreeding and maximise farm profit of commercial dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {122-126},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {The objective of this study was to demonstrate the potential benefits of computerised mate selection in a commercial crossbred dairy herd of 411 cows mated to 10 Holstein-Friesian and 10 Jersey bulls. Mate selection was carried out using an evolutionary algorithm to perform single- or multiple-objective optimisation to maximise farm profit ($/4.5 t DM) and/or minimise inbreeding level of progeny. Restrictions were placed on the total number of mating pairs, the maximum number of matings per bull and per cow. Selection and mate allocation of bulls and cows at random produced progeny with average farm profit of $94 and inbreeding level of 1.70\%. Mate selection applied to maximise farm profit yielded a mating set with an average farm profit of $181 and inbreeding level of 2.07\%. Mate selection applied to minimise inbreeding level selected a mating set with average farm profit of $65 and inbreeding level of 0.03\%. Mate selection applied to optimise farm profit and minimise level of inbreeding with a weighted ratio of 1:1, resulted in a mating set with average farm profit of $176 and inbreeding level of 0.44\%. The results demonstrate that in the short term, inbreeding can be controlled at the same time as maximising farm profit using a computerised mating selection program with multiple-objective optimisation. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Harris BL and Pryce JE}
}
@conference {41506,
	title = {A survey of goat meat acceptability in Japan},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {208-211},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {A questionnaire survey was designed to gauge consumer interest in goat meat. The questionnaire was responded to by 98 households living in or near Tokyo. The main results of the survey are as follows. 1) Impression of goat meat; 61\% of the respondents indicated that goat meat was {\textquotedblleft}not common in their home{\textquotedblright}. 2) Consumer experience; only 16\% of the respondents had experience of eating goat meat and they felt goat meat is {\textquotedblleft}smelly{\textquotedblright} (50\%), {\textquotedblleft}tender{\textquotedblright} (38\%) and {\textquotedblleft}delicious{\textquotedblright} (31\%). 3) The two main reasons why consumers have not eaten goat meat were {\textquotedblleft}lack of purchasing opportunity{\textquotedblright} (78\%) and {\textquotedblleft}don{\textquoteright}t feel like eating it{\textquotedblright} (18\%). 4) Options to promote goat meat consumption; 52\% of respondents who have not eaten goat meat were prepared to purchase if it was available in the supermarket at a reasonable price and if recipes were added with the meat package. 5) Reasons for people not purchasing goat meat included {\textquotedblleft}dislike of new meat{\textquotedblright} and {\textquotedblleft}pity for the goat{\textquotedblright}.
These results show that goat meat can be promoted to the Japanese households as {\textquotedblleft}a new product{\textquotedblright} if the price is reasonable and recipes are added to the package. However, a considerable number of market strategies need to be implemented to achieve the acceptance of goat meat by Japanese consumers. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41486,
	title = {Use of breeding values for live weight to calculate individual live weight targets for dairy heifers},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {118-121},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Replacement heifers need to reach specific target live weights (LW) to ensure they calve as two year olds, and subsequently achieve high milk yields and good fertility. Currently, different LW targets are recommended for heifers based on their expected mature LW according to appearance or breed. However, the mature LW is difficult to estimate without knowledge of the animals. genetic potential for LW. The objective of this paper is to develop and validate a growth model which uses estimated breeding values for LW (EBV LW) of individual heifers of any breed to calculate target LW from birth to maturity. Predicted live weights are presented for a range of four EBV LW, from {\textendash}40 to 100 kg. These values were very similar to other published target values. Data from the Dexcel Holstein Friesian Strain Trial was used to validate the model with respect to LW and age at puberty. For LW at puberty the predicted values were significantly correlated (P<0.05), but were marginally higher (3-5\%) than the actual values. A report can be formulated to enable farmers to identify individual heifers which are below (or above) their target LW at any date },
	issn = {1176-5283},
	author = {Bryant JR and Holmes CW and Lopez-Villalobos N and McNaughton LR and Brookes IM and Verkerk GA and Pryce JE}
}
@conference {41403,
	title = {Beef traceability systems in Japan - how should New Zealand prepare?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {49-52},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Interviews were held with National Federation of Agricultural Cooperative Association (NFACA), Ministry of Agriculture, Forestry and Fisheries (MAFF) and New Zealand Meat Board staff to describe current beef traceability systems operating in Japan following the BSE incident there in 2001. Some suggested actions for the New Zealand beef industry to become more competitive against domestically produced beef are described from a traceability perspective. It is concluded that there is no sustainable, complete (from farm to consumer) beef traceability systems being operated in Japan, not only by domestic producers or retailers, but also by overseas companies. Domestic traceability systems are either facing financial problems (NFACA system) or functional problems (MAFF system). This means that if New Zealand adopts a farm to consumer traceability system in the Japanese market, it will be the pioneer and will be recognised, as "clean and green", not only by nuance, but also in practice by the Japanese consumer. The main problem for New Zealand adopting such a traceability system in the Japanese market is balancing anticipated expenses versus expected financial return to the New Zealand beef producer. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41408,
	title = {Effect of genetic merit on the estimated partitioning of energy towards milk production or liveweight gain by Jersey cows grazing on pasture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {69-72},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Data from the 1999/2000 season of the Stratford demonstration farm stocking rate trial was used to estimate metabolisable energy intakes (MEI) and the amount of metabolisable energy (ME) partitioned into milk, maintenance and liveweight (Lwt) changes of Jersey cows of either high genetic merit (HGM) (average milksolids breeding value of 28 kg) or low genetic merit (LGM) (average milksolids breeding value of 11kg). Least-square mean yields for HGM and LGM cows were 327 and 289 kg of milksolids per cow respectively. HGM cows partitioned a significantly higher proportion of MEI into milk than LGM cows in early (0.67 vs 0.63; P<0.01), peak (0.59 vs 0.57; P<0.05), mid (0.58 vs 0.56; P<0.01) and late lactation (0.54 vs 0.51; P<0.01) (HGM vs LGM respectively). In early lactation, HGM cows utilised more body reserves for milk production (-0.05 vs -0.01, for HGM and LGM respectively). These results confirm that HGM cows partition more ME to milk throughout lactation than LGM animals for a range of feeding levels on grazed pasture. The greatest difference occurred in early lactation, resulting in increased body tissue loss and a greater negative energy balance in HGM cows. },
	issn = {1176-5283},
	author = {Bryant JR and Lopez-Villalobos N and Holmes CW and Pitman GD and Brookes IM}
}
@conference {41409,
	title = {Evidence of a genotype by feeding level interaction in grazing Holstein-Friesian dairy cattle at different stocking rates},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {73-76},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Lactation yields and estimated breeding values (EBVs) for protein, fat and milk were obtained for individual cows in a farmlet trial carried out at Dexcel in Hamilton, using Holstein-Friesian cows, to test for the existence of a genotype by environment interaction across the range of feeding levels, and EBVs typically found on New Zealand pasturebased dairy farms. At very low levels of feeding, with yields of 267 - 307 kg milksolids per cow (kg MS/cow), regression coefficients of lactation yield on EBVs were not significantly different from the expected value of 1. At high levels of feeding, with yields of 383 - 411 kg MS/cow, most of the regression coefficients for yields of protein, fat and milk on EBVs were significantly greater than 1. The results of this study show that at low levels of feeding the actual differences in production between cows, which differ in EBVs correspond to the actual differences in EBVs, whereas at high levels of feeding the difference in milk yields between genetic groups are greater than the difference in EBVs. This constitutes a form of genotype x environment interaction, in which genotype is measured as breeding values, and has important practical and economic implications for dairy farms, and for the expected value of genetic improvements. },
	issn = {1176-5283},
	author = {Bryant JR and Holmes CW and Lopez-Villalobos N and MacDonald KA and Brookes IM}
}
@conference {41423,
	title = {Frequency of mastitis and variation in somatic cell counts throughout the lactation in cows managed organically or conventionally; Year 1},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {63},
	year = {2003},
	month = {Jan},
	pages = {138-139},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Queenstown},
	abstract = {Interest in organic milk production is growing in New Zealand. At present milk is being collected from 13 organically certified farms in the North Island and 66 farms have been identified as either certified organic or interested in converting from conventional production (Stevenson, 2002).
Massey University started a trial on August 2001 to monitor the difference between organic and conventional dairy farming systems, and to provide New Zealand dairy farmers with proven information on differences between the two systems. A key focus of the organic farming system is the maintenance of health and well-being of cows in the herd, without the routine use of conventional methods (e.g., antibiotics). Mastitis has been recognised as the main disease problem. The objective of this report is to present results on the variation in somatic cell counts (SCC), frequency of clinical mastitis (CM) and frequency of acute levels of SCC of cows managed according to either organic or conventional farming practices for the season 2001 to 2002, the first year after the change to organic farming. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Scott J and Smith Z and Holmes CW and Shadbolt NM and Harvey TG}
}
@conference {41334,
	title = {Effect of grazing undrenched weaner deer on chicory or perennial ryegrass/white clover pasture on gastrointestinal nemotode and lungworm viability},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {143-144},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Internal parasites can reduce animal performance (Moss \& Vlassoff, 1993) and lungworm has been known to cause death in young deer (Mackintosh et al., 1984). Increasing numbers of drench resistant parasite populations being found on farms throughout New Zealand (Sangster, 1999) and pressure from consumers to reduce anthelmintic input for fear of residues in pastoral-based food products (Williams, 1997), signifies a need to find alternative methods of internal parasite control. Hoskin et al. (1999) found that undrenched weaner deer grazed on chicory did not have impaired growth rates and faecal egg counts were lower compared to similar animals grazed on perennial ryegrass/white clover pastures. This suggests that chicory has the potential to be used in farming systems to reduce the negative impact of internal parasites.
This study looked at the viability of internal parasites that had travelled through the digestive tracts of deer grazing chicory (Cichorium intybus) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens)- dominant pasture. The hatching ability of gastrointestinal nematode eggs, the development of gastrointestinal nematode and lungworm larvae and the motility of L1 lungworm larvae were measured. The study also determined the effect of adding condensed tannins (CT), extracted from chicory, to rumen and abomasal fluid on L1 lungworm larval migration. CT are a group of phenolic secondary plant compounds found in chicory at concentrations of approximately, 4.2g/kgDM (Terrill et al., 1992). },
	issn = {1176-5283},
	author = {Schreurs NM and Molan AL and Lopez-Villalobos N and Barry TN and McNabb WC}
}
@conference {41322,
	title = {Genetic opportunities to improve milk value in New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {90-94},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The value of milk in New Zealand can be improved by altering its composition by genetic means (crossbreeding, selection, and biotechnology). Breed changes and crossbreeding influence the value of milk, but the choice of breed is usually dominated by attributes other than milk composition. Responses to within-breed selection are influenced by the emphasis placed on milk components relative to other animal attributes. The relative economic emphasis among the traits in the objective, and the genetic and environmental relationships between measured performance attributes will influence the rate of progress in milk quality, milk value and farm profit. Transgenic modification of the bovine genome offers the possibility of quantum shifts in milk characteristics but requires further research, education and testing in order to gain consumer acceptance. The manufacture of high-value dairy products for specific markets will likely require the segregation of milks from different farms. The long-term nature of genetic improvement dictates that today{\textquoteleft}s vision shared by producers, processors and AB companies must be in concert with future needs of consumers if real opportunities are to be realised. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ and Holmes CW}
}
@conference {41331,
	title = {Organic beef in Japan - is there any room for New Zealand?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {128-132},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {In September 2001, an incident of mad cow disease (bovine spongiform encephalopathy) occurred in Japan. Japanese people now seek improved safety of beef meat and organic beef might fulfil part of this requirement. In this study, interviews were held with owners of a pasture-based beef production farm on the island of Hokkaido in Japan, which is widely recognized among the Japanese consumers as a {\textquoteleft}healthy and ecological{\textquoteleft}. The farming system is pasture-based, raising Hereford, Angus and crossbreeds, rather than the traditional Japanese Black breed. It is necessary to use grain-based concentrate feed when the animals are being finished. These feeds are fully imported, non-genetically modified, and {\textquoteleft}post harvest free feed (PHF){\textquoteleft}. Feeding imported organic grains to cattle for fattening is contrary to the Codex organic regulations settled in 2001. Therefore, it would appear difficult to achieve domestic organic beef meat production in Japan. There are opportunities for New Zealand beef exporters to expand their market in Japan. To achieve this expansion, there are two major issues to address. Firstly, intensive market promotion to the Japanese consumer will be necessary using New Zealand{\textquoteleft}s "clean and green" image and pasture-based finishing systems. Secondly, research work is necessary to develop special beef commodities which fit the Japanese consumer{\textquoteleft}s taste. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41342,
	title = {Responses to poplar supplementation in ewes grazing drought pasture during mating},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {174-176},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Over the past 160 years, poplar and willow trees have been extensively planted on New Zealand pastoral land for shade and shelter, aesthetics and conservation purposes (Wilkinson, 1999).  In North Island East Coast regions, some hill-country farmers are pruning the branches of poplar and willow trees to feed them to livestock during the late summer and autumn dry period, to supplement low-quality pastures.  Drought poses a serious management issue for farmers in the East Coast regions of both the North and South Islands and predictions suggest droughts will become more frequent and severe in the future (Salinger, 2000).  Supplementation with conserved forages, such as hay and silages, or grains such as barley, is a common management practice for farms suffering drought conditions (Leng, 1992).  However, many East Coast hill-country farms have little or no flat land on which to produce hay or silage.},
	issn = {1176-5283},
	author = {McWilliam EL and Barry TN and Kemp PD and Lopez-Villalobos N and Cameron PN}
}
@conference {41343,
	title = {Use of Lotus corniculatus to increase sheep production under commercial dryland farming conditions without the use of anthelmintics},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {62},
	year = {2002},
	month = {Jan},
	pages = {177-178},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Legumes are an important component of feeding systems in temperate zones to fix nitrogen and to produce high quality forage as a feed for livestock. However, marginal protein deficiency exists when ruminants are fed on fresh temperate forages due to high degradation rates of forage proteins in the rumen. Consequently, there is a large absorption of NH3 from the rumen, leaving absorption of essential amino acids (EAA) from the small intestine that is below animal requirements for these AA (Barry, 1982).
Condensed tannins (CT) in Lotus corniculatus (Birdsfoot trefoil) reduce rumen protein degradability and increase EAA absorption from the small intestine (Waghorn et al., 1987). Separate feeding experiments with sheep have shown that CT in lotus increased wool production and milk secretion (Wang et al., 1996a\&b) and both ovulation rate during mating, and lambing percentage (Min et al., 1999: Min et al., 2001), all with no increase in voluntary feed intake (VFI). In addition, lambs fed lotus accumulated fewer dags than lambs grazed on perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture (Leathwick \& Atkinson, 1995). Each of these effects was measured in separate specific experiments.
The objective of this study was to assess the effect of feeding Lotus corniculatus upon wool production and lamb weaning weight under commercial dryland farming conditions without anthelmintic drench input, using a systems approach, where effects upon animal productivity and parasites were measured in the same experiment. },
	issn = {1176-5283},
	author = {Ramirez-Restrepo CA and Barry TN and Lopez-Villalobos N and Kemp PD and Pomroy WB and McNabb WC and Harvey TG and Shadbolt NM}
}
@conference {41286,
	title = {A comparison of dairy farming between New Zealand and Japan},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {203-206},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The productivity and financial performance of dairy farms in New Zealand and Japan (Hokkaido) were analysed. Relative to Hokkaido, New Zealand has lower yield of milk solids per cow, but higher production per hectare because of their pasture grazing systems. The value of milk solid is much higher in Hokkaido than New Zealand (NZ$14.7 vs. NZ$3.5/KgMS), and the total expenses of producing milk solids are much higher in Hokkaido than in New Zealand (NZ$11.5 vs. NZ$3.0/KgMS). New Zealand has a lower variable cost, but higher fixed expenses and higher cash surplus ratio per farm compared with Hokkaido. There is also remarkably high interest expenditure in New Zealand caused by non-subsidised loan procurement from finance organisations. Total farm expenses per cow in New Zealand is only at about 1/10 of Hokkaido expenses. There is a marked difference in financial structures between the two countries, especially in turnover ratios of gross assets. The results suggest that it is important for dairy farmers in Hokkaido to consider not only cost savings achieved through grazing systems, but also to consider that grazing systems make only poor utilisation of capital. },
	issn = {1176-5283},
	author = {Ozawa T and Lopez-Villalobos N and Blair HT}
}
@conference {41287,
	title = {Feed intake capacity in Holstein-Friesian cows which differed genetically for body weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {207-209},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The feed intake capacity (FIC) of pregnant, non-lactating Holstein-Friesian cows, selected for either high (H) or low (L) breeding values for live weight (LW), was measured when fed to appetite on hay (7.5 MJ ME/kg DM in 1998) and on pasture (11.1 MJ ME/kg DM in 1999). The H cows were heavier than the L cows in both years (546 v 482 kg; 540 v 464 kg in years 1 and 2 respectively), and the H cows ate significantly (P<0.01) more feed than the L cows in both years (12.5 v 11.1 kg hay DM, and 13.1 v 11.6 kg pasture DM per day in years 1 and 2 respectively. Regression analysis showed that for each 100-kg increase in LW, daily DMI per cow increased by 1.43 and 1.81 kg respectively in 1998, and 1999. Regression analysis of the data after conversion into log10 , showed that DMI was proportional to LW0.66 and LW0.65 in 1998 and 1999 respectively. These results indicate that the genetically heavier cows ate more DM than the genetically lighter cows. Nevertheless, the difference between maintenance costs and FIC (or "net" FIC) may be similar for both strains, so that the smaller intake of the lighter cows does not disadvantage their productive capacity. },
	issn = {1176-5283},
	author = {Caicedo-Caldas A and Lemus-Ramirez V and Holmes CW and Lopez-Villalobos N}
}
@conference {41291,
	title = {Intake, live weight and feed-conversion efficiency of lactating Holstein-Friesian dairy cows which differ genetically in live weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {221-223},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of this study was to measure during mid lactation the effect of live weight on the metabolisable energy intake by cows in two lines of Holstein-Friesians selected for heavy or light mature live weight. Yields of milksolids and intakes of dry matter were estimated during two 3-day faeces collection periods. Live weights were measured once in each period. Intakes of pasture dry matter by individual cows were estimated using the alkane technique. Least-square means for live weight, daily yield of milksolids, intakes of dry matter, intakes of metabolisable energy and feed-conversion efficiency for the heavy and the light line were obtained. Linear regression coefficients of metabolisable energy intake on metabolic live weight and yield of milksolids were obtained. Mean values were 15.0 vs. 15.3 kg of dry matter eaten/cow daily, 532 and 488 kg live weight, 1.58 and 1.55 kg milksolids/cow daily, and 108 and 106 g milksolids/kg of dry matter eaten, for the heavy and the light line respectively. The partial regression coefficient of metabolisable energy intake on metabolic live weight was 0.65 MJME/kg LW 0.75 for both lines, similar to commonly reported values. Both lines had similar feed-conversion efficiencies. These data, from 73 grazing cows, generally support other data, and show that live weight does affect maintenance requirements as expected for cows in the heavy and light live weight lines. But they disagree with previous data because the heavy cows did not have higher intakes.},
	issn = {1176-5283},
	author = {Tolosa MX and Caicedo-Caldas A and Holmes CW and Lopez-Villalobos N}
}
@conference {41290,
	title = {Lactation curves for milk traits, live weight and body condition score for heavy and light Holstein-Friesian cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {217-220},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Two genetic lines of Holstein-Friesian cows divergently selected for heavy and light live weight but with similar genetic merit for farm profitability have been developed at Massey University since 1989. The objective of this experimental project was to evaluate differences in production, fertility and feed efficiency between the two lines when they are managed on grazed pasture and submitted to a seasonal system of reproduction. This paper describe the shapes of the lactation curves for yields of milk, fat and protein, live weigh and body condition score of the two lines using the gamma function. Parameters of the gamma function for each of the traits were estimated for each of 84 cows using daily yields of milk, fat and protein and weekly measurements of live weight and body condition scores recorded during the production season 1998-99. Live weights and body condition scores of mature heavy and light cows at calving were 495 and 436 kg and 4.7 and 4.8 units, respectively. Respective values for first-calving cows were 397 and 352 kg live weight and 4.9 and 4.9 units of body condition score. Peak yields of milk, fat and protein for mature heavy (27.6 litres, 1.30 kg and 0.90 kg) were higher than for mature light (25.6 litres, 1.21 kg and 0.86 kg) cows but differences were not significant. Peaks of yield occurred between 27 and 31 days after calving with no significant differences between lines of cows. There were no significant differences between lines for changes in body condition score and persistency of milk, fat and protein production during lactation of mature cows. Compared to mature cows, first-calving cows had lower peak yields of milk, fat and protein. First-calving light cows were the most persistent and maintained the highest body condition score during lactation. Total predicted yields of milk, fat and protein for mature heavy (4,048 litres, 194 kg and 133 kg) were not significantly different from those for mature light (3,774 litres, 182 kg and 127 kg) cows. These results show that there are no significant differences in the shape of the lactation curve for heavy or light mature cows, but first-calving light cows maintained higher body condition score in late lactation. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Lemus-Ramirez V and Holmes CW and Garrick DJ}
}
@conference {41288,
	title = {Milk yield, prolactin and IGF-1 in cows which calve in Autumn; preliminary report},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {210-212},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The objective of this study was to investigate causes of reduced peak milk yield of autumn-calving cows. This experiment is part of a study that is comparing autumn- and spring-calving systems. Two groups of 17 multiparous, Friesian cows that had calved between April 1 and May 6 were fed either ad libitum on grazed pasture (G), or restricted pasture (10kg DM/cow/day) supplemented with maize silage (6kg DM/cow/day) (G + MZ) for a period of 21 days. Milk yield by cows on G increased by 6.2 litres over the 21-day period and was significantly higher (P< 0.01) than the yields of cows on G + MZ. Milk prolactin concentration had no significant association with milk yield. There were higher average plasma concentrations of IGF-1 in the G group (range 104-140ng/mL vs. 95-107ng/mL) that corresponded to higher average milk yields but IGF-1 concentration had no significant association with milk yield. Milk yield and milk prolactin concentration were negatively associated with condition score and plasma IGF-1 concentration was positively associated with condition score. },
	issn = {1176-5283},
	author = {Wrigley J and Holmes C and Lopez-Villalobos N}
}
@conference {41097,
	title = {Genetic parameter estimates for lamb survival in Romney sheep},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {59},
	year = {1999},
	month = {Jan},
	pages = {121-124},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lamb survival is a trait of economic importance in sheep production. Most lamb losses occur within 1 to 2 days of birth. Losses may be attributed to the lamb and to the behaviour of the dam. Maternal effects are environmental for the offspring but are genetic for the dam. ANIMALPLAN has separately evaluated individual and maternal attributes. Difficulties arise to genetically evaluate animals for survival because this trait has a binomial distribution whereas most analytical procedures assume normality. The objective of this study was to estimate heritabilities and genetic correlations for direct and maternal genetic effects on two underlying scales (probit and logit) for lamb survival in order to implement a new procedure of genetic evaluation. Variance components were obtained by Restricted Maximum Likelihood (REML) procedures after logit or probit transformation of the data with a linear mixed model using records from 25,874 lambs born over the period 1989 to 1995 in a prolific Romney flock. The lambs were the progeny of 218 sires and 6,771 dams. The model included fixed effects of sex, year, litter size at birth and age of dam and the random effects for direct genetic, maternal genetic and maternal environmental influences. Lambing and survival percentages were 178\% and 87\%, respectively. The estimates of heritability on the logit scale were 0.01, 0.03 and 0.04 for direct, maternal and total genetic effects, respectively. The proportion of total variance explained by maternal environmental influences was 0.09. The estimated genetic correlation between direct and maternal genetic effects was - 0.26. Similar estimates were obtained on the probit scale. Estimates will be lower for the observed scale. These results indicate a greater opportunity for improving survival by manipulating the environment rather than by selection. However survival analysis is an important component of quality assurance in a genetic improvement scheme. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ}
}
@conference {40989,
	title = {Effects of selection and crossbreeding on industry returns from whole milk powder, butter and casein in the New Zealand dairy industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {64-67},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The effects of selection and crossbreeding on New Zealand dairy industry return were evaluated with a deterministic simulation model over 25 years. Several crossbreeding strategies involving Holstein-Friesian (F), Jersey (J) and Ayrshire (A) cattle were evaluated. These strategies were straightbreeding, upgrading to F (UPGF), upgrading to J (UPGJ), upgrading to A, and two- and three-breed rotational crosses. Total production of milk, fat, protein, lactose and ash were calculated assuming that 12,000 kg dry matter/ha was eaten for 1,224,911 ha. Yields of standardised whole milk powder (WMP), casein and butter were calculated. For the base year all the protein was utilised in WMP and for subsequent years, some increases in protein were sold in the form of casein. Casein and WMP were valued at $6.00 and $3.31 per kg respectively over the 25 years, whereas butter was valued at $3.00 per kg for base year production levels and $0.45 per kg for marginal increases in production. Production for the base year was 9,874 million l milk, 467 million kg fat, 359 million kg protein and 464 million kg lactose which yielded 1,263 million kg WMP and 157 million kg butter for an industry return of $4,646 million. Relative to the base year, UPGF resulted in the largest increase in WMP (128 million kg, 10\%), the lowest increase in casein (36 million kg) and increased returns by $639 million (14\%). UPGJ resulted in the lowest increase in WMP (73 million kg, 6.0\%), the largest increases in butter (67 million kg, 43\%), casein (65 million kg) and returns ($662 million, 14\%). Two-breed rotational (F,J) resulted in product flows for WMP and butter that were above the intermediate between UPGF and UPGJ but return that was equal to UPGJ. Selection within-breed in combination with crossbreeding can increase industry returns. However, the net financial outcome of all changes must be assessed taking into account farm expenses, income from culled stock and factory costs in processing milk with different composition in order to determine optimum crossbreeding strategies. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ and Spelman RJ and Holmes CW and Blair HT}
}
@conference {40971,
	title = {Experimental designs for Quantitative Trait Loci detection in the New Zealand dairy industry},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {6-9},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Detection of loci that affect quantitative traits such as milk production has been undertaken with daughter and
granddaughter designs in the N.Z. dairy industry. Two other experimental designs, selective DNA pooling of trait
extremes and the use of first cross Holstein-Friesian{\textendash}Jersey bulls, offer the opportunity to detect more loci than the current
two designs. Selective DNA pooling involves the collective pooling of DNA from daughters at each extreme (high and
low) of the trait distribution. A sire family of 100,000 daughters with DNA pools created from the top and bottom 1\%
of progeny pooled has the same power (probability of detection) as approximately 5,000 progeny being individually
genotyped with less than 1\% genotyping effort. Crossbreeding in the New Zealand dairy industry opens up the opportunity
to identify QTL alleles that contribute to the genetic differences between the two breeds. Identification of breed specific
QTL alleles can be achieved at a power of 90\% based on some 600-1500 progeny from matings of F1 Holstein-Friesian
x Jersey bulls to F1 cows.},
	issn = {1176-5283},
	author = {Spelman R and Lopez-Villalobos N and Garrick D}
}
@conference {40990,
	title = {Growth curves and productivity of Holstein-Friesian cows bred for heavy or light mature live weight},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {68-72},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {This paper presents data for live weights (LW) from birth to maturity, and for yields of milk and milksolids (MSY) per lactation, from two lines of Holstein-Friesian cows bred for heavy (H) or light (L) mature LW. Compared with the Brody, Gompertz and Logistic functions, the Von Bertalanffy function provided the best fit to the LW data, and prediction from this function has been used in the following analyses. The breeding values (BV) for LW of the sires (H: 86.3 kg; L: 31.0 kg) and maternal grandsires (MGS) (H: 55 kg; L: 38 kg) used to develop the H and L LW lines were higher (P<0.001) for the H line than for the L line, and they were significantly associated with the actual birth weight (H: 41 kg; L: 35 kg) and mature live weight (H: 520 kg; L: 467 kg) of the cows. The heavy sires also had significantly higher BV for yield of milk (H: 1037 l; L: 737 l), milkfat (H: 33.0 kg; L: 27.5 kg), and milk protein (H: 31 kg; L: 22 kg), and the H cows produced more milk (H: 4708 l; L: 4323 l), and MSY (H: 364 kg; L: 348 kg) than the L cows. However, L sires had slightly higher (P = 0.07) value for Breeding Worth than the H sires (H:37; L:46), and there were only small differences in yields of milk or MSY between the two lines when these were expressed per kg of LW, per kg of LW0.75 or per tonne of dry matter required (H: 84 kg MSY/tonne DM; L: 87 kg MSY/tonne DM). The results indicate that the extra MSY by the H cows (+ 16 kg) almost compensated for the effect of their extra LW (+ 46 kg), so that the H cows were only slightly less efficient than the L cows, as predicted by their respective sire{\textquoteright}s Breeding Worth. },
	issn = {1176-5283},
	author = {Garcia-Muniz JG and Holmes CW and Garrick DJ and Lopez-Villalobos N and Wickham BW and Wilson G and Brookes IM and Purchas RW}
}
@conference {40883,
	title = {Across-breed genetic evaluation of New Zealand dairy goats.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {43-45},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The New Zealand dairy goat industry consists of 187 herds (33,500 does), from which 60 herds (12,600 does) supply milk for the Dairy Goat Co-operative. Most of the milk is used to manufacture whole milk powder for niche markets. Farm profitability can be increased through identifying and selecting superior animals for traits of financial importance such as milk yield. Across-breed estimated breeding values (EBVs) for milk yield adjusted for days in milk (MYA), unadjusted milk yield (MYU) and days in milk (DIM) of Saanen, Nubian, British, Toggenburg and crossbred dairy goats spread across 20 herds were estimated by Best Linear Unbiased Prediction (BLUP) procedures. A repeatability model was used to analyse the first eight lactation yields and included effects of herd-year-month, parity, additive genetic and permanent environment. Coefficients of breed composition and heterosis (assuming equal heterosis among any of the breeds) and days in milk were considered as covariables. Heritability and repeatability were 0.36 and 0.63 respectively. Evaluations were based on 6,517 lactation records of 3,856 does and 83 sires. Average milk production was 548 litres over an average lactation spanning 200 days. Pure-bred Saanen does had longer lactations (DIM) and out-produced other breeds in MYA and MYU. Two year old does produced an extra 150 litres of milk compared to one year old does. Peak production was at 5 years of age then production declined gradually. Young does had longer lactations than old does. Average EBVs for different breeds compared to a Saanen base were for MYU Nubian -291, British -242 and Toggenburg -106 litres, MYA -177, -193 and -51 litres and DIM -40, -17 and -19 days for each breed respectively. First cross heterosis was 105 litres (19\%) for MYU, 52 litres (9.5\%) for MYA and 18 days (9\%) for DIM. This first prototype evaluation allows the selection of does and bucks based on their estimated genetic merit and provides for routine genetic evaluation in the future. },
	issn = {1176-5283},
	author = {Singireddy SR and Lopez-Villalobos N and Garrick DJ}
}
@conference {40877,
	title = {Effect of crossbreeding strategies on long-term rates of genetic gain in New Zealand dairy cattle.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {22-25},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Crossbred cows tend to be more profitable than straightbred cows because they fit the present milk payment system and show favourable heterosis for milk traits. This may encourage greater use of crossbred cows eroding the number of potential bull mothers (active cows) thereby reducing genetic progress. The objective of this research was to evaluate the effects of crossbreeding on active cow numbers and genetic gain over 25 years.
A deterministic model was used to calculate the number of cows and the breeding worth (BW) of Holstein-Friesian (F) and Jersey (J) bulls each year. Three strategies were considered: upgrading to F (UPGF); upgrading to J (UPGJ); and some two-breed rotational mating plans. In 1996, sizes of F and J active populations were taken to be 250,000 and 76,400 cows and mean bull BWs were $72 (F) and $82 (J).
After 25 years of UPGF the number of active F and J cows were 1,520,000 and 13,000, the BWs of F and J bulls were $245 and $213 and genetic gains of F and J bull teams were 8.5 and 4.25 $BW/year. UPGJ had the opposite effect. Mating 10\% of {\textbullet}2/3F cows to F bulls and 10\% of -1/3F cows to J bulls (ROTATE10) for 25 years led to active F and J populations of 70,200 and 75,800 cows, BWs of F and J bulls of $227 and $230 and genetic gains for F and J bull teams equal to 7.0 $BW/year. Results suggest that widespread adoption of a rotational crossbreeding scheme could be achieved without penalising annual genetic gain in bulls. However, annual recruitment of new active cows should be routinely monitored to ensure long term gain will be maintained. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ}
}
@conference {40818,
	title = {Profitability of rotational crossbreeding programmes in commercial dairy herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {216-220},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Dairy farm profitability can be increased through the use of superior  cows in the lactating herd. Genetic superiority is determined by additive  genetic effects and heterosis (present in crossbred animals). Profitability is  the difference between income (sale of milk, bobby and salvage animals)  and costs (related to the number of cows in the herd and the land area  farmed). At comparable production, bigger cows consume more feed  reducing their profitability per unit feed consumed. Previous studies have  identified the high productivity of first-cross cows comprising Holstein- Friesian (F) and Jersey (J) breeds. In a self-replacing herd, first-cross (F1)  animals will not be continuously available unless some straightbred animals  are maintained. One approach for exploiting heterosis in a self-replacing  herd, is to make use of rotational crossbreeding. This paper reports  profitabilities of some rotational crossbreeding programs in comparison to  farming straightbred dairy animals. A model was used to estimate on an annual basis, the nutritional, biological  and economic performance of whole herds consuming 12,000 kg dry matter  per ha. Expected performances for straight- and cross-bred cows comprising  F, J and Ayrshire (A) breeds, were obtained using estimates of breed and  heterosis effects derived from Livestock Improvement},
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ}
}
@conference {40616,
	title = {Accounting for scale effects in genetic evaluation of dairy cattle.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {276-280},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Lactation records of dairy cows calving between 1986 and 1989 were  
obtained from the Livestock Improvement Corporation of the New Zealand  
Dairy Board.  There were milkfat yields from 2,004,854 lactations in 83,805  
contemporary groups.  The data were divided into three equal-sized subsets  
based on average level of production (scale) in the contemporary group; these  
being (kg milkfat {\textpm} sd) High (H), 172 {\textpm} 28; Medium (M), 152 {\textpm} 26; and Low  
(L), 139 {\textpm} 25.  The objectives of this study were to provide evidence of  
heterogenous variance and to identify the best of three methods to stabilise  
the variance of milkfat yields for use in the genetic evaluation of New Zealand  
dairy cattle based on a best linear unbiased prediction procedure using an  
across breeds animal model which will be implemented in July 1996. 
 
The methods investigated for the accounting of scaling were adjustment based  
on: contemporary group standard deviation (SD); contemporary group means  
(MEAN); and logarithmic transformation (LOG) of milkfat yield.  The overall  
correlation between contemporary group means and standard deviations was  
0.44.  This value was reduced to 0.31 in SD-transformed data, -0.27 (MEAN)  
and -0.24 (LOG). 
 
Correlations between breeding values for sires estimated from the independent  
data sets using a mixed model but without adjustment for scale were 0.76, 0.73  
and 0.78 in the L-M, L-H and M-H comparisons.  These were lower than  
expected correlations of 0.85, 0.85 and 0.87, reflecting inaccuracies in sire  
evaluation when scaling is ignored.  Calculated correlations were similar for  
SD and MEAN (0.78, 0.75 and 0.80; 0.78, 0.74 and 0.78), but LOG reduced  
the calculated correlations (0.73, 0.69 and 0.75). 
 
Results confirm the problem of scaling on genetic evaluation of New Zealand  
dairy cattle and indicate other methods need to be studies to correct the  
scaling problem. },
	issn = {1176-5283},
	author = {Lopez-Villalobos N and Garrick DJ and Harris BL and Blair HT}
}
