Features of polymorphism and genetic structure of the leptin gene in Red Steppe cows

Abstract

The leptin gene affects milk producing ability of cows, the regulation of energy metabolism and the duration of economic use of dairy cows. The features of the polymorphism of the leptin gene in Red Steppe cows in West Siberia were studied for the first time. The breeding stock of this breed accounts for about 60% of the total dairy cattle of the Omsk Region, and therefore the research findings on the features of the polymorphism of the leptin gene and the dependence of dairy productivity of cows become relevant for breeders involved in the breeding of such animals. The genotyping of 126 cows from one of the farms in the Omsk Region revealed two C and T alleles and three CC, CT and TT genotypes. The frequency of the C allele (0.6) prevailed over the T allele (0.4). A small TT genotype with a frequency of 15% was identified. The maximum occurrence was in cows with the CT genotype - 49%. The genetic balance of the population was confirmed by the heterozygosity test (1.02), the value of χ² (0.10) and the Wright fixation index (-0.02). The percentage of homozygous cows was 51% with a coefficient of genetic variability of 48.3% which characterized the livestock as genetically diverse. A significant effect of the TT genotype of the leptin gene on milk yield (5882 kg) and milk production coefficient (1019 kg) during the third lactation was determined in cows of the Red Steppe breed. The high content of the main components of milk belonged to cows with a small TT genotype, but no reliable confirmation was found. We advise that breeders take into account the research findings on the occurrence of leptin gene genotypes and their effect on the manifestation of economic traits when carrying out breeding work with breeding stock of Red Steppe cattle.