Characteristics of milk productivity and milk technological properties from black-and-white cows with different allelic variants of the kappa-casein gene (CSN3)

The purpose of research is to study the level of milk productivity and quality of milk of cows of the Altai population of the Holstein black-and-white breed in connection with various variants of the kappa-casein gene (CSN3). The production base for genetic research was the breeding plant of Uchkhoz Prigorodnoye JSC, located in Barnaul. To study single nucleotide polymorphism (SNP) of the CSN3 gene, we collected blood samples from 100 cows of the breeding core at the age of 2-3 lactation. Detection of CSN3 SNP rs 43703017 (g.87390632A>G; Ser176Gly) was carried out by real-time PCR. It has been established that the most common kappa-casein genotype in the herd of the Altai population of black-and-white cattle is CSN3AA - (57.1 ± 5.92) %, and the most common allele is CSN3A - (74.3 ± 3.69) %. The CSN3B allele and the CSN3BB genotype occur in (25.7 ± 3.69) and (8.6 ± 0.34) %, respectively. Analysis of the productive parameters of animals depending on structural differences in the CSN3 gene showed that despite the tendency to increase milk yield in cows carrying the heterozygous genotype CSNАB, milk obtained from animals with the CSNBB genotype, which contains 0.01 more fat, has the best cheese-making qualities; 0.04 % and protein by 0.19; 0.11 % compared to similar indicators in carriers of the CSN3AA and CSN3AB genotypes. The highest content of dry matter in milk and SOMO was also observed in animal carriers of the CSN3BB genotype - 13.24 and 8.72 %. The rate of enzymatic (rennet) milk coagulation was higher in animals with the CSNВВ genotype by 6.6 and 15.8 %, respectively, than in cows carrying the CSNAA and CSNАB genotypes. This makes milk obtained from animals with the CSNВВ genotype the most profitable for cheese production.