MILK PRODUCTIVITY AND MILK QUALITY OF COWS WITH DIFFERENT LEP GENOTYPES AND LINEAR AFFILIATION

Abstract

A review of the scientific literature has shown that the genotype by loci of the Leptin (LEP) gene and linear affiliation to the leading Holstein breed of cows have an impact on milk productivity and the quality of their milk. The purpose of our research was to study the milk productivity and qualitative composition of the milk of Tatarstan-type cows with different genotypes according to the loci of the Leptin gene and linear belonging to the Holstein breed. The research was carried out in the conditions of the agricultural company "Agrofirma Rassvet" of the Kukmorsky district of the Republic of Tatarstan on the livestock of 79 cows of the Tatarstan type. The Tatarstan type is one of the leading dairy cattle breeds bred in the Republic of Tatarstan, and created by crossing the Kholmogorsky, Black and White, and Holstein breeds, while the bloodline was 1/8 Kholmogorsky + 1/16 Black and White + 13/16 Holstein. As a result of a molecular genetic study (PCR-RFLP), the animal population was sorted into groups, taking into account the genotype by the loci of the Leptin gene. The conducted studies have shown that in Tatarstan-type cows after the first lactation, the highest milk yield indicators, the amount of fat and protein in milk were noted in animals with the leptin gene genotypes LEP/CC and LEP/CT in comparison with peers of the LEP/TT genotype. However, in terms of the mass fraction of fat and protein in milk, the trend was reversed. Also, among the cows of the Tatarstan type, according to the first lactation, the highest values of milk productivity indicators (milk yield, amount of milk fat and protein) are in cows with the LEP/CC genotype of linear belonging to the Holstein breed, namely W. Ideal 933122 and R. Sovering 198998.