Milk producing ability and productive longevity of Holstein cows depending on leptin gene polymorphism

Abstract

The research goal is to analyze the level of milk producing ability, reproductive ability and duration of productive longevity of Holstein cows depending on the polymorphism of the leptin gene (LEP). This gene encodes the corresponding hormone - leptin which is involved in the regulation of energy metabolism by changing the intensity of metabolic processes and a close relationship with growth hormones, sex hormones and the thyroid gland. At the same time, a change in the nucleotide sequence in the gene affects the activity of the produced leptin which can also affect the productive longevity of cattle. In this regard, we conducted research on the farm of the AO Uchkhoz Prigorodnoe. Blood samples from 100 Holstein cows were taken to study the single nucleotide polymorphism (SNP) of the LEP gene. It was found that cows carrying the LEP^CC genotype were characterized by a longer economic longevity by 9.3 and 1.2% and the age in lactations at culling by 15.9 and 12.0%, respectively, as compared to the carriers of the LEP^CT and LEP^TT genotypes. The maximum milk producing ability was demonstrated by first-calf heifers with the LEP^TT genotype, while in adult animals increasing their producing ability, the maximum lifetime milk yield was by 4% higher in the presence of the LEP^CC genotype. Indirect evidence of high functional stress on the body of cows with the LEP^TT genotype is a higher content of butterfat and protein in milk against the background of high milk yields. When analyzing the relationship of the polymorphism of the gene under study and the reproductive function no reliable trends were found. However, in our opinion, this has a predictive value when analyzing the selection effect, since this genotype is more associated with milk quality and does not have a negative effect on the fertility and reproductive potential of animals in the population under study.