@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 = {Implications of using an extended lactation to change from a spring-calving to an autumncalving farm system in South Taranaki},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {143-149},
	address = {Online},
	abstract = {Recent changes to pasture-supply curves in South Taranaki, and the availability of winter milk premiums have increased farmer
interest in changing from a spring-calving to an autumn-calving farm system. One approach to changing the season of calving
from spring to autumn is to extend the calving interval (CI) by delaying the mating period by ~8 months, so that they next calve
in autumn and undertake an extended lactation [>305 days in milk (DIM)]. A large-scale farmlet experiment was established in
South Taranaki to investigate the production and reproduction responses of cows using this approach. In June 2017, 602 springcalving
cows were allocated to two farmlets. In one farmlet (SPR) 301 cows were mated in October to maintain a 12-month CI
spring-calving pattern. In the other farmlet (AUT, n=301 cows), mating was delayed for eight months, and cows underwent an
extended lactation (mean DIM, 488; max DIM, 577) to calve next in autumn 2019. The experiment analysed two lactations for the
AUT farmlet and two and a half lactations for the SPR farmlet. Across the total experimental period, milksolids (MS) production
was similar between farmlets (1,194 vs. 1,174 kg MS/cow), however, cows in the AUT farmlet were fed more supplementary feed
[2,371 vs. 1,951 kg dry matter (DM)/cow]. The extended lactation changed the relationship between feed supply and herd demand,
which led to excessive BCS gain and ryegrass staggers for AUT farmlet cows. Further research is required to examine grazing
management during extended lactations and to assess the economic implications of this approach.

Keywords: autumn calving; spring calving; extended lactation},
	issn = {1176-5283},
	author = {Jarman JWM and Kay JK and Neal M and Donaghy DJ and Tozer P}
}
@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 = {Technical note: A comparison of editing criteria for lying-behaviour data derived from three-dimensional accelerometer devices on grazing dairy cows},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {80},
	year = {2020},
	month = {09/2020},
	pages = {8-13},
	address = {Online},
	abstract = {Shorter, more-frequent lying bouts (LB) could be used to predict calving and as an indicator of animal discomfort and ill-health. In
this technical study, we reviewed the literature to describe criteria for removing false short LB, caused by minor movements, from
accelerometer data using IceRobotics technology. Using an existing dataset of grazing cows, we compared unedited with edited
accelerometer data after applying three different LB thresholds (LB <33 s, <=2 min, and <4 min were removed) within IceQube
and IceTag accelerometers. Daily lying time, LB (no./d) and LB duration were derived from either IceQube or IceTag devices
for 146 and 159 multiparous cows, respectively. Very-short LB were more common in IceTag than IceQube data. Applying a
shorter LB criterion (<33 s) to the IceQube dataset produced minimal differences between unedited (8.8{\textpm}3.6 no./d; n=64,512 lying
records) and edited data (8.3{\textpm}3.4 no./d; n=60,463). In contrast, we observed large differences between unedited (307{\textpm}293 no./d;
n=2,305,693) and edited data (8.8{\textpm}4.1 no./d; n=66,139) when a longer LB criterion (<=2 min) was applied to the IceTag dataset.
Removing short LB that are unlikely to represent true behaviour will improve the interpretation of lying behaviour data; however,
prospective studies are needed to determine the most-suitable LB criterion.

Keywords: lying behaviour; grazing cows; accelerometer},
	issn = {1176-5283},
	author = {Hendriks SJ and Phyn CVC and Turner S-A and Mueller KR and Kuhn-Sherlock B and Donaghy DJ and Huzzey JM and Roche JR}
}
@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 = {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 = {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 = {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: 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 = {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 = {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}
}
