RELATIONSHIP OF COMPLEX GENOTYPES OF DGAT1, GH, PRL AND BLG GENES WITH MILK PERFORMANCE INDICATORS FOR HOLSTEIN DAIRY COWS OF DOMESTIC SELECTION

The improvement in the selection process using molecular genetic methods allows more effectively assess the genetic potential of breeds, populations and individual animals, adjusting the focus of selection work, influencing the traits that characterize the technological value of milk (fat content, protein content, etc.). As a result, it allows reducing the time spent on breeding animals with high milk productivity. The studies were conducted at the Obukhovo dairy complex of the I.P. Senko agricultural production cooperative in the Grodno district of the Grodno region (Republic of Belarus). When assessing the associated influence of the DGAT1, GH, PRL and BLG gene genotype complexes and the milk productivity indices of domestically bred Holstein dairy cows, it was established that in terms of the mass fraction of fat and the amount of milk fat in milk, in most cases, the animals with the DGAT1KKGHLLPRLAABLGAB gene genotype complex had the highest indices. It was established that in animals of all gene genotype complexes over three lactations, medium and high values of positive correlations were identified between milk yield and the amount of milk fat in milk; milk yield and the amount of milk protein in milk, as well as between the amount of milk fat and the amount of milk protein in milk (r=0.80...0.99).