POLYMORPHISM OF THE CSN3 GENE IN SIMMENTAL HERDS AND ITS VARIABILITY DURING HOLSTEINIZATIONT.S. Khoroshilova, G.M. Goncharenko, N.B. Grishina, K.V. Zhuchaev, L.I. Lisunova and L.N. Korobova
Dairy farming in the Altai Republic mainly specializes in the production of hard cheeses and butter from the milk of Simmental cows, which are most adapted to mountain conditions. The breed has good health, strong bones, and hoofed horns and quickly adapts to various natural and ecological conditions. However, cows often have uneven development of the lobes, the âgoat shape of the udderâ, and insufficient expression of the milk type. The Simmental breed is everywhere improved by the red-mottled Holstein breed to increase milk production and improve the shape of the udder and the speed of milk production, which is economically justified. The phenotypic features and characteristics of economically valuable traits of the obtained crossbreeds are described quite well, but the changes in the polymorphism of genes associated with these traits are not sufficiently studied. The purpose of our research is to compare the polymorphism of the CSN3 gene as a marker of milkâs cheese applicability in Simmental herds and to study its changes in the holsteinization. Studies have established that the ratio of genotypes is approximately the same CSN3ÃÃ â 55- 58%, CSN3AB â 34-36%, and CSN3BB â 7-10% in herds of the Simmental breed without targeted selection for the CSN3 gene. However, the use of animal typing by the CSN3 gene in the breeding process increased the frequency of the desired CSN3AB and CSN3BB genotypes for the herd to 48.1 and 17.7%, respectively, and to 54.8 and 30.9% for individual lines. Holsteinization can significantly reduce the frequency of the desired CSN3BB genotype by 6% without taking into account the CSN3 genotypes of the gene.