Effect of csn2, csn3 and lgb genes on milk production traits of montbèliarde dairy cattle

The aim of this study was to investigate the effects of CSN2 (coding beta-casein), CSN3 (coding kappa-casein and LGB (coding beta-lactoglobulin) genes polymorphisms on milk production traits in a Montbèliarde herd from a Romanian dairy farm. In order to achieve the objective, 34 cows with first lactation finished were sampled. Milk samples were analyzed for fat, lactose and total solids by infrared absorption methodology. Genetic variants of milk proteins were identified by using polyacrylamide gel electrophoresis containing dithiothreitol and urea. For testing the state of genetic equilibrium in this population, according to Hardy-Weinberg theory, we used chi-square test (χ2). The highest observed frequencies were for beta-casein A2 allele (β-CN*A2), K-CN*B, respectively β-LG*B. Cows with β-CN A2A2, K-CN AB and β-GB AA genotypes produced a significantly higher milk yield. Beta-casein genotype A1A2 positive effect may be used in order to obtain higher fat, protein and casein content in milk.