Association of genotypes of cows of the Kholmogory breed by beta-casein with milk productivity

The aim of the study is to identify frequency occurrence various allelic variants and genotypes beta-casein in cows Kholmogory breed their relationship with dairy productivity. tasks research are genotyping cattle by locus establishing its connection qualitative quantitative indicators As objects for there were taken 150 1st, 2nd 3rd lactation. An allele-specific variant PCR method (AS-PCR) was used A1 A2 beta-casein. result it had been established that studied part herd, 23 % animals A2A2 genotype, 43 A1A1 genotype 34 A1A2 genotype. For 100 days first lactation, showed highest value milk yield. Animals 305 lactation yield amount protein, however, difference not statistically significant compared Genotype has lower all parameters studied, a relative A2A2. Thus, CSN2 promising area scientific research, results can be as marker selection improving herds breed.