Capa-casein gene polymorphism in cows of different breeds of dairy productivity

Genetic polymorphism of milk proteins, in particular kappa-casein, is of considerable research interest due to its possible associations with economically important traits of dairy cattle. The aim of the study was to determine the polymorphism of the kappa-casein gene and its association with signs of milk productivity in cows of different breeds. Polymorphism of the kappa-casein gene was studied in cows of Ukrainian red-spotted dairy (UCHERM), Ukrainian black-spotted dairy (UCHRM), Montbeliard (M) breeds and crossbred cows obtained by crossing cows of Ukrainian red-spotted dairy breed with Mongolians. DNA studies were performed in the Department of Animal Genetics and Biotechnology of the Institute of Animal Breeding and Genetics nd. a. M.V.Zubets NAAS using the PCR-RFLP method. As a result of research, three genotypes of the kappa-casein gene were identified: AA, AB, BB. Genotypes AA and AB were found in all studied groups of cows, genotype BB was found only in cows of Montbeliard breed with a frequency of 0.366. The highest hopes for 305 days of the first lactation among all studied cows were in crossbred cows with genotype AB (7029 kg), the lowest - in crossbred animals with genotype AA (6359 kg). According to the distribution of genotypes and alleles of the kappa-casein gene, domestic breeds of UCHRM and UCHERM are similar in genetic structure and have a low concentration of B-allelic variant, apparently due to the fact that these breeds were created by reproductive crossing with Holstein breed, in populations of which this allele quite low. The presence of such genotypes in the studied groups of first-borns is determined by the peculiarities of selection work in the herd of SE "DG" Niva "of the Institute of Animal Breeding and Genetics named after MV Tooth of NAAS ». Research results genotypes and alleles of the kappa-casein gene is an additional genetic characteristic of animals, which makes it possible to create herds with the desired characteristics of milk productivity