The effect of lipid metabolism and body weight genes at the first calving on the dairy productivity of Tatarstan-type cows

The optimal live weight at the first calving of cows is an indirect criterion for early prediction of milk productivity during lactation and indicators of productive longevity of cows. In this regard, the aim of the research was to study the effect of live weight at the first calving on the milk productivity of Tatarstan-type cows with different genotypes according to lipid metabolism genes ( OLR1, DGAT1, LEP ). The research was carried out on 79 cows of the Tatarstan type kept on the territory of the agricultural company "Agrofirma Rassvet" of the Kukmorsky district of the Republic of Tatarstan. Genotypes of lipid metabolism genes in the studied livestock were determined by PCR and RFLP ( OLR1, DGAT1 ) and AS-PCR ( LEP ). Studies have been conducted on the complex effect of live weight at the first calving and genotypes according to the genes of the low-density lipoprotein receptor ( OLR1 ), diacylglycerol-O-acyltransferase ( DGAT1 ) and leptin ( LEP ) on the manifestation of milk productivity (yield, mass fraction of fat and protein in milk, milk fat and protein yield) of breeding cows of the Tatarstan type. In general, studies have shown that the best values of milk productivity were in Tatarstan-type cows with OLR1/AC , DGAT1 / АК , LEP/CC, LEP/CT , LEP/ТT genotypes, having the highest live weight at the first calving (481-520 kg, 521 kg or more), with the exception of peers with OLR1/СC, DGAT1 / АА genotypes, which had higher productivity with the lowest live weight at the first calving (up to 480 kg).