Estimation of Genetic Parameters for the Protein Profile in Danish Holstein Milk

Abstract Text: Seven protein traits were measured in bovine milk by LC-MS using samples from 370 animals: Protein%, casein (CN)%, κ-CN%, α_S1-CN%, α_S2-CN%, β-CN%, β-lactoglobulin (β-LG%) and α-lactalbumin (α-LA%). A genomic relationship matrix calculated based on the HD SNP information of these animals was used in the univariate and bivariate analysis of the protein traits. Hertitabilities ranged from 0.77 for κ-CN% to 0 for α_S1-CN% (SE: 0.13-0.21). The genetic correlation between β-CN and κ-CN was low (0.01 ± 0.53) whereas the genetic correlation of α_s2-CN with both β-CN and κ-CN was high (< -0.90). Furthermore α-LA% and β-LG% were highly correlated (0.71 ± 0.14) and had a low correlation to CN% (0.08 ± 0.25; -0.08 ± 0.30, respectively). In this study κ-CN% and the whey proteins showed a high heritability whereas α_S1-CN%, α_S2-CN% and β-CN% showed a low heritability in Danish Holstein cattle.

Keywords: Dairy cattle, Protein profile, Genetic parameters