Genotyping of cattle of Holstein breed to LEP gene and analysis its association with milk productivity

Abstract

The productive traits of cattle are controlled by a large number of genes. There is a association between certain genetic markers and productive traits of animals, and in the process of breeding a change in the allelofund of herds aff ects the productive traits of animals. The purpose of the research was to make genotyping of cattle of Holstein breed to LEP gene and analyze its association with the milk productivity of fi rst-calf heifers. Studies of milk productivity in the context of the polymorphism of LEP gene demonstrate the superiority of animals with TT genotype in terms of milk yield, fat mass fraction in milk, milk fat yield, milk protein and total milk fat and protein yield. The fi rst-calf heifers carrying the homozygous allele C differed favorably in the content of the mass fraction of protein. The fi rst-calf heifers with the homozygous TT genotype had high milk productivity and had a high milk coeffi cient. Depending on the genotype the average monthly milk yield and the character of lactation curves changed. Animals with TT genotype has shown high milk yield during the fi rst fi ve months of lactation (from 2 to 6), the peak occurred in the third month after calving. A similar trend in this indicator was observed in the fi rst-calf heifers with CC genotype, but they had high milk productivity for four months, the peak of their productivity was noted in the second month of lactation. Lower indicators for the herd were found in animals with the heterozygous TC genotype. Having a stable and smooth, without jumps, lactation curve their results were minimal for the studied livestock, with a fixed maximum average monthly milk yield in the fourth month of lactation.