@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}
}
