ОЦЕНКА КОРОВ-ПЕРВОТЁЛОК ЧЁРНО-ПЁСТРОЙ ПОРОДЫ ПО ДНК-МАРКЕРАМ, АССОЦИИРОВАННЫХ С ХОЗЯЙСТВЕННО-ПОЛЕЗНЫМИ ПРИЗНАКАМИ

Abstract

At present time are widely used genetic markers as means in the selection of highly productive animals. Since the genes: CSN3 (kappa-casein), PIT-1 (pituitary-specific transcription factor), PRL (prolactin), GH (somatotropin) are polymorphic and encode various proteins, the study of their influence on the productive traits of cattle is relevant. In this regard, the goal of the work is to determine the influence of complex genotypes of the studied genes on the milk productivity of first-calf cows of the Black-and-White breed bred in the collective farm-breeding plant «Kazminsky» in the Kochubeevsky district of the Stavropol Territory. The place of research is the Department of Genetics and Biotechnology, VNIIOK, a branch of the North Caucasian Federal National Research Center. This article presents the results of DNA genotyping of allelic polymorphism for the CSN3, PIT-1, PRL, GH genes using PCR-RFLP methods in first-calf cows of the Black-and-White breed. It was established that these genes in the studied sample are polymorphic. The frequency of occurrence of the desired CSN3B allele in the studied sample was 0.23. The presence of alleles PIT-1A and PIT-1B of the pituitary-specific transcription factor gene was noted with a frequency of occurrence of 0.52 and 0.48. A feature of the PRL gene polymorphism was the fairly high frequency of occurrence of the PRLA allele (0.60). In this study sample of dairy cattle, the frequency of occurrence of the desired GHL allele of the somatotropin gene was 0.62. All variants of complex genotypes were also identified and their relationship with milk productivity in black-and-white cows was noted. The study sample was dominated by animals carrying complex desirable genotypes, consisting of four and three marker alleles of three and two genes (CSN3AB/PIT-1BB/GHLV; CSN3AB/PIT1AB/GHLL or PIT-1AB/PRLAB/GHLV; PIT-1AA/GHLL ) - 46.7 %. Milk yield per lactation between groups of black-and-white first-calf cows with different complex genotypes ranged from 5839.14 to 8611.33 kg. The mass fraction of fat in milk ranged from 3.93 to 4.04 %, and protein from 2.99 to 3.14 %.