Genetic parameters for major milk fatty acids and milk production traits of Dutch Holstein-Friesians.

ABSTRACT

The objective of this study was to estimate genetic parameters for major milk fatty acids and milk production traits. One morning milk sample was collected from 1,918 Holstein-Friesian heifers located in 398 commercial herds in The Netherlands. Each sample was analyzed for total percentages of fat and protein, and for detailed fatty acid percentages (computed as fatty acid weight as a proportion of total fat weight). Intraherd heritabilities were high for C40 to C160, ranging from 0.42 for C40 to 0.71 for C100. Saturated and unsaturated C18 fatty acids had intraherd heritability estimates of approximately 0.25, except for C182 cis-9, trans-11, which was 0.42. Standard errors of the heritabilities were between 0.07 and 0.12. Genetic correlations were high and positive among C40 to C140, as well as among unsaturated C18, but correlations of C40 to C140 with unsaturated C18 were generally weak. The genetic correlation of C160 with fat percentage was positive (0.65), implying that selection for fat percentage should result in a correlated increase of C160, whereas unsaturated C18 fatty acids decreased with increasing fat percentage (-0.74). Milk fat composition can be changed by means of selective breeding, which offers opportunities to meet consumer demands regarding health and technological aspects.