Effects of Stearoyl-CoA Desaturase 1 and Sterol Regulatory Element Binding Protein Gene Polymorphisms on Milk Production, Composition and Coagulation Properties of Individual Milk of Brown Swiss Cows

Sa？etak Associations between stearoyl-CoA desaturase (SCD) and sterol regulatory element binding protein (SREBP-1) gene polymorphisms and milk production, composition (fat, protein, and casein content), acidity (pH and titratable acidity) and coagulation properties (MCP), namely rennet coagulation time (RCT, min) and curd firmness (a30, mm) were investigated on individual Brown Swiss milk. A total of 294 cows from 16 herds and progeny of 15 sires were milk-sampled once. Th e additive effects of SCD and SREBP-1 genotypes on the aforementioned traits were analyzed through Bayesian linear models. The SCD gene was associated with protein content, casein content and a30. Lower protein, casein and a30 was observed for milk yielded by SCD V than A cows, whereas for other traits the effect was trivial. Animals carrying the L allele of SREBP-1 showed higher fat content than animals carrying the S allele. These results suggest a possible use of these loci in gene-assisted selection programs for the improvement of milk quality traits and MCP in Brown Swiss cattle, although large scale studies in different breeds are required