ASSOCIATION OF THE BETA-CASEIN GENE POLYMORPHISM WITH MILK YIELDS OF PLANNED COW BREEDS IN THE REPUBLIC OF BASHKORTOSTAN
The frequency of alleles and beta-casein genotypes occurrence and their interconnection with milk yields of cows of planned cattle breeds in the Republic of Kazakhstan (Black-Spotted, Bestuzhev and Simmental breeds) are considered in the article. It is found that the homozygote genotype CSN2AA is the most often occurring one. The Simmental cows had the advantage by the frequency of the CSN2AB genotype. The CSN2BB genotype was not often observed in cows of all the three breeds under study, its frequency ranged from 12.4 to 16.1%. The frequency of CSN2A allele was higher than that of CSN2B allele in cows of all the breeds under study. The maximum value of CSN2B allele - 0.34 was observed in Simmental cows, the minimum value - 0.24 was observed in Bestuzhev cattle. The highest milk yields were registered in Black-Spotted cows of the CSN2AA genotype, its value being 4810.21 kg. The maximum protein content (3.68%) had the cows of the CSN2BB genotype.