Associating leptin gene polymorphism (site R25C) with economically useful traits

The establishment of the influence of genetic factors on economically useful traits is important for breeding and increasing the productivity of farm animals. The aim of the study was to establish a relationship between the polymorphism of the leptin gene (site R25C) with milk productivity and with live weight indicators during the growth and development of cows of the Kholmogorsky breed. The study was conducted on the breeding stock of cattle in JSC Kholmogorsky Stud Farm. The analysis of the frequency of occurrence of single nucleotide polymorphism R25C genotypes in Kholmogorsky cows showed the predominance of the heterozygous RC genotype (57.14%), while the frequency of the C allele was 0.62, and the R allele was 0.38. The results of the study of the effect of leptin gene polymorphism (site R25C) on milk productivity and on the development of live weight in different age periods of Kholmogorsky cows were also obtained. Statistical analysis (the Kraskel-Wallis criterion, the Mann-Whitney U-criterion) did not reveal a significant effect of the single nucleotide polymorphism R25C on milk productivity. Live weight analysis showed that animals with the RR genotype were characterized by significantly higher live weight at birth, at 18 months and at first insemination compared with carriers of other genotypes. In addition, cattle with the RR genotype have a longer period of productive use. The results obtained indicate that the R allele of the leptin gene has a positive effect on the growth and development of animals of the Kholmogorsky breed. The revealed patterns can be used to increase the efficiency of breeding work.