Associations between milk protein genetic polymorphisms and milk production traits in Merino sheep breed

作者：Corral J M; Padilla J A^*; Izquierdo M

来源：Livestock Science, 2010, 129(1-3): 73-79.

DOI：10.1016/j.livsci.2010.01.007

• Merino sheep
• Milk production traits
• DNA polymorphism
• CSN2
• CSN3
• LGB

Genotypic effects of beta-casein (CSN2), kappa-casein (CSN3) and beta-lactoglobulin (LGB) on milk yield, and fat, and protein percentages were estimated in Merino breed ewes by using an animal model. Casein genotype effects were estimated separately and then combined as a composite genotype. The CSN2 gene was polymorphic (alleles A and G) in the exon VII in the Merino population analysed. The frequencies of the alleles A and G were 0.7644 and 0.2356, respectively. Although CSN2 gene polymorphisms were reported, there were not any previous studies relating these polymorphisms with milk production and composition traits. Sheep carrying the CSN2 *GG genotype presented the highest milk production yield. In relation to CSN3 gene, the most frequent genotype corresponded to the genotype, K(3)K(3). The K(1)K(4) and K(3)K(3) genotypes were associated with the highest productions for milk yield and the genotypes K(1)K(4). K(2)K(2) and K(3)K(5) were associated with the highest values for fat, protein and lactose percentages, respectively. The composite beta-kappa-CN genotypes, AGK(3)K(5) and GGK(3)K(3) were associated with the highest milk yield on the first milk recording and 120-day milk yield. Genotypes AGK(2)K(3), AGK(2)K(2) were associated with the highest fat and protein percentage, respectively. In addition, the LGB BB genotype had a favourable effect on milk yield.

• 出版日期2010-4