Characteristics of the genetic structure of the β-casein gene of producers approved for use in Ukraine in 2020

Abstract

The modern topical issue in dairy cattle breeding is the study of the relationship between hereditary factors that determine the types of proteins in milk. Casein is the main component of milk proteins and is represented by three fractions - alpha (CSN1S1), beta (CSN2) and capa (CSN3). The content of individual casein fractions depends on the breed of cows. Scientists point out some grand questions as for the promotion of milk proteins, like beta-casein, affecting on such disorders as type-1 diabetes, schizophrenia, autism and the sudden death of an infant. The economic component that will ensure the attractiveness of creating the dairy herds completed with animals of genotype A2 A2 is the higher price of raw milk in comparison with conventional milk. The aim of this work is to evaluate the genotype of bulls-producers by the beta-casein gene, which are allowed to be used in Ukrainian farms in 2020. It is established that the majority of such bulls-producers are evaluated by the genotype of betta-casein. The largest proportion of bulls with the desired A2A2 genotype was found in red Danish and red Norwegian bulls. A greater proportion of A1A1 genotypes are characterized by Holstein bulls of red-mottled color. The largest proportion of the desired A2 allele was found in bulls of red Danish, red Norwegian and Guernsay breeds. Producers of Holstein and Ayshire breeds were characterized by a smaller proportion of this allele. It was found that the use of sperm of bulls approved for use in 2020 with the A2A2 by β-casein genotype on the breeding stock of domestic breeds will improve the economically useful characteristics of offspring, and will contribute the desired genotype of cows. As a result of the analysis of the genotype of Holstein and Swiss breeds that were used in breeding farms of Sumy region over the past three years, we found that 38 Holstein bulls were used in breeding farms and in breeding plants, among which 11% were evaluated by the β-casein gene. Among 12 Shvits bulls that were used in farms of the region, only 42% were evaluated by the β-casein genotype. This confirms that the work with the formation of dairy herds completed with animals of genotype A2 A2 in Sumy region was not carried out. Key words: breed, bull, β-casein, genotype, allele, daughters milk productivity.