The genotypic profile of milk proteins in Holstein cows raised in South of Brazil

Abstract

Genotyping in dairy cattle allows knowing the alleles and genotypes associated with milk proteins that affect yield and milk quality. This study aimed to verify the genotype profile for κ-casein I and II (κ-CN), α-s1-casein (α-CN) and β-lactoglobulin (β-LG), for Holstein cows raised in southern Brazil, where there is no scientific evidence on the presence of these alleles in dairy herds. Hair follicles samples from each animal were used for DNA extraction and genotyping. We calculated the allelic and genotypic frequencies for four types of milk protein variants in the population, and a chi-square test was employed to see whether the population of animals used was in Hardy-Weinberg equilibrium. Allele A and AA genotype showed the highest frequency for both κ-CN (56.77 to 80.36%). For α-s1-CN and β-LG, the B allele was the most frequent, as BB (80.26%) and AB (47.15%), respectively. Due to the presence of alleles associated with protein levels in milk, we concluded that these herd cows present milk technological properties interesting to produce dairy products.