Yield and milk quality of cows with different genotypes of thyreoglobulin

The aim of research to study milk productivity and milk quality Black-and-White * Holstein breeds of cows of first calving with different genotypes according for thyreoglobulin gene (TG5). The studies were conducted in conditions of breeding reproducer of "Dusym" Atninsky district of the Republic of Tatarstan on cross-bred animals of Black-and-White breed. As a result of molecular genetic studies (PCR-RFLP-analysis) animals were divided into groups depending on genotype for TG5 gene. Only two genotypes CC and CT for TG5 gene were revealed in this sample of animals. It was found that cows of first calving with CT genotype for TG5 gene were superior in milk yield by 1 day of lactation and lactation by 1,2 kg (P