The aim of this work was to study the reproductive capacity of fresh cows with various genotypes of kappa-casein gene and diatsetilglitserin O-acetyl transferase. It was revealed that at an early age of insemination and calving, animals have a lower body weight at first calving. Cows on the gene locus of kappa-casein AB and BB, gene of butterfat AK and KK were observed elongated expectancy service- and between calving periods (106 and 394 days, 105 and 400 days) and a lower coefficient of reproductive ability and Doha’s index (0.93 and 46.2, 0.91 and 45.8), which suggests a slight decrease in their reproductive capacity.

Thanks to DNA diagnostics method it has become possible to identify the genotypes of marker genes of servicing bulls, that makes effective use of manufacturers with the desired gene alleles of economically useful features and is now the main task of breeding in cattle. The analysis and synthesis of polymorphism according to DNA markers of productivity: the kappa-casein (CSN3), diacylglycerol O-acyltransferase (DGAT1), beta-lactoglobulin (LGB), prolactin (PRL), growth hormone (GH), thyroglobulin (TG5), leptin ( LEP) in bulls of Tatarstan type of Kholmogorsk breeding, black-and-white and Kholstein breeding, belonging to tribal enterprises of Tatarstan: JSC Parent enterprise “Elita”, JSC “Menzelinsky breeding enterprise”, JSC “Bugulminsk breeding enterprise”. It was found that the bulls of Tatarstan type of Kholmogorsk breeds have the highest frequency of heterozygous genotypes for most genes, so according to CSN3 genotype AB - 34.2%, according to PRL genotype AB - 30.4%, to TG5 genotype TC - 35.9%, to LEP genotype TC - 66.7% and homozygous genotypes for the genes DGAT1, LGB, PRL, GH, LEP, respectively, AA genotype (47.2%), BB (48.7%), BB (2.2%), VV (20,0%), SS (33.3%). Genetic equilibrium is disrupted on gene of diacylglycerol acyltransferase in bulls of Tatarstan type of Kholmogory breed (χ2 = 4,72; P <0.05) and a black-and-white breed (χ2 = 3,91; P <0.05), and according to the somatropin gene only Kholmogory breed producers (χ2 = 5,42; P <0.05).