Assessment of breeding and productive qualities of holstinized cattle depending on polymorphism of the kappa-casein gene (СSN3)

Classical selection and selection methods are not enough for successful and efficient selection and breeding work with cattle. DNA testing of polymorphic forms of genes encoding milk proteins, in particular the kappa-casein gene (CSN3), is increasingly being introduced into animal husbandry practice. In this regard, we studied the breeding and productive qualities of Holstein cattle depending on the polymorphism of the kappa-casein gene (CSN3). It was found that among the black-and-white breeding bulls of JSC “Barnaul Breeding Enterprise” (Altai Krai, Russian Federation), the BB genotype associated with protein and fat milk content is recorded in 7 % of animals, a third of the herd of bulls are heterozygotes for the B allele – 35 %. Selection aimed at increasing milk yield determined the preferential use of bulls with the CSN3 AA genotype (58 %), which is a marker of higher milk yields in cows, which contributed to high consolidation of the A allele. It was found that daughters obtained from bulls with the CSN3 AB genotype reliably exceeded cows obtained from bulls with the CSN3AA genotype in milk yield by 10% (590 kg), in milk fat and protein yield by 12.4 % (29.9 kg) and 9.8 % (18.1 kg) and milk fat content by 0.09 % (p < 0.001). The highest degree of realization of genetic potential by the value of parental index of sires was established by the content of fat in milk at 95.3–99.5 % and protein content at 89.8–94.8 %, at the same time, by milk yield, the realization of genetic potential corresponds to 59.4–69.7 %. The highest milk productivity was noted in mother cows with heterozygous genotype CSN3AB and amounted to 8543 kg.