Influence of protein and hormone genes on productivity and longevity of Simmentals

The research was conducted in the eld of dairy cattle breeding with the use of genetic markers (SNPs) in order to study their relationship with the period of economic use of cows and their productivity. The object of the study was 186 cows of Simmental breed from the farm situated in Novosibirsk region. To study cows’ productivity (milk yield, fat, protein, the number of lactations) the data of zootechnical records was used. Molecular genetic research and statistical processing of experimental results were carried out according to generally accepted methods. The paper presents the results of the herd assessment by polymorphism of CSN3, PRL, BLG, TNF-α-824 genes, whose genotype frequency corresponds to a particular breed. Gene balance is not disturbed (χ2 = 0.147– 2,306). Homo and heterozygosity are approximately in the same ratio, except for the homozygosity of the gene PRL (0,736). Genotypes of cows desirable for productive longevity were identi ed: BLGBB, PRLAA, PRLAB, TNF-αGG, whose number in the third lactation was over 70% in relation to the rst. The highest productive longevity was observed in animals with genotypes BLGBB and PRLAA, where 9.0% and 8.3% of their number, respectively, had a fourth lactation. Genotype BLGAA can be referred to as a desirable genotype for milk productivity. The difference from carriers of genotype BLGBB was 624 kg (p < 0.01). In the gene TNF-α, a higher yield in the second lactation at 787.3 kg was observed in cows with genotype TNFAA, compared to genotype TNF-αGG (p < 0.01). The same animals were found to have an increased content of fat in milk by 0.07% and protein by 0.05% (p < 0.01).