POLYMORPHISM OF CSN3, bGH AND bPRL GENES IN CONNECTION WITH MILK QUALITY TRAITS IN KOSTROMA CATTLE BREED
Polymorphysms of the kappa-casein (CSN3), prolactin (bPRL-RsaI) and growth hormone (bGH-AluI) genes in Kostroma cattle breed from the Karavaevo farm of the Kostroma region were revealed. Distributions of the most frequent alleles and genotypes of the genes studied were the following: allele B (0,624) and genotype AB (0,528) of the CSN3 gene, allele A (0,720) and genotypes AA (0,496) and AB (0,448) of the bPRL gene, and allele L (0,940) and genotype LL (0,880) of the bGH gene. The observed (Hobs) and expected (Hexp) heterozygosities for all genes studied did not differ significantly from each other. Study of the effects of the genes on milk production traits for 305 days of the first lactation revealed the following: significantly better in milk yield and milk protein were animals of the LL genotype of the bGH gene, 6456 kg and 208,5 kg, correspondingly, in fat content – animals of the VL genotype (4,38 %). The most preferred genotype in fat content of the CSN3 gene was BB genotype exceeded AA genotype (more on 3,25 %). Significant differences for the bPRL gene were not found.