@conference {40766,
	title = {Associations between milk protein genetic variants and production traits in New Zealand dairy cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {24-27},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Records on 7574 first lactation cows were used to investigate the  associations between milk protein genetic variants and 305-day milk, fat,  and protein yields. Friesians, Jerseys and Ayrshires and their crosses were  represented in the data. Milk samples were typed for 3 casein (CN) proteins  as1-CN (B,C), b-CN (A1, A2), k-CN (A,B) and 1 whey protein b- lactoglobulin (LG) (A,B). The model used to describe the data included the  additive genetic effect of animal and the four protein phenotypes. The interaction between breed and as1-CN phenotype and between breed  and b-CN phenotype was significant (P<0.05) for milk, fat and protein  yields while the interaction between breed and k-CN phenotype was  significant (P<0.05) only for protein yield. The interactions associated with  the as1-CN and k-CN phenotypes were scale effects while the interactions  associated with b-CN resulted from reranking of protein phenotype across  the breeds. Friesian and Jersey as1-CN BB cows had higher (2.8\% and  0.8\%, respectively) milk production and lower (0.3\% and 1.2\%,  respectively) protein production than BC animals while the differences  between the phenotypes for fat production were small. The b-CN A2 allele  was associated with increased production in the Friesians with A2A2 cows  producing approximately 2\% more milk, fat and protein than A1A1 cows.  The opposite effect was found in Jerseys where A2A2 cows produced 3-4\%  less milk, fat, and protein than A1A1 cows. The B allele of k-CN was  associated with a 0.6 to 3.5\% increase in production. The b-LG BB  phenotypes produced approximately 1.3\% less milk and protein and 1.2\%  more fat than the AA phenotypes. The dominance effect was not significant  (P<0.05) for any of the protein phenotypes. },
	issn = {1176-5283},
	author = {Winkelman AM and Wickham BW}
}
