PROLACTIN GENE POLYMORPHISM IN THE DAIRY CATTLE POPULATION OF THE OMSK REGION

The purpose of the study is to determine the polymorphism of the prolactin gene in the dairy cattle population of the Omsk Region. Objectives – to carry out genetic monitoring of the cow population for the presence of the desired allele of the PRL gene in the genotype;to determine the frequency of genotypes and alleles of the PRL gene in the studied population. The object of the study is a population of dairy cattle of the red steppe breed, bred at 2 enterprises – a breeding reproducer and a leading commodity farm in the Omsk Region. In cattle bred at the enterprises of the Omsk Region, with the greatest frequency there were animals that were not carriers of the PRL gene leading to/associated with the studied phenotype. In the enterprises of the Omsk Region, with the highest frequency, there were animals that were not carriers of the PRL gene leading to/associated with the studied phenotype, which had values in the range from 0.74 to 0.8. Analysis of the frequency distribution of heterozygous genotypes for the studied PRL gene was only from 0.40 to 0.52. The frequency of occurrence of genotypes with the desired allele A among animals bred in a commercial farm turned out to be higher by 0.12 compared to the frequency of occurrence in a breeding reproducer. In the studied animals of the red steppe breed, bred at the enterprises, there was no homozygous genotype for the A-allele. In a breeding reproducer, with the age of animals, the frequency of carriers of the desired allele increases. 58 % of first-calf heifers are carriers of the A allele of the PRL gene. The maximum frequency of occurrence of genotypes with the associated allele A of the PRL gene in the group of cows of the 3rd lactation is 90 %, and only 10 % of cows in this group have the BB genotype. The revealed frequency of genotypes in the context of lactations makes it possible to judge the organization of selection and breeding work in herds. To increase in the population of animals with the A/A and A/B genotypes, it is necessary to select and assign sires with the A/A genotype for the PRL gene to the cows of this population.