Технологические свойства и качественный состав молока и молочной сыворотки коров в зависимости от влияния генотипов по генам каппа- и бета-казеина

Abstract

Studies were carried out on 118 cows of black and white Holsteinized breed with certain genotypes according to beta- (CSN2) and kappa-casein (CSN3) genes. The aim of the study was to examine the qualitative composition and technological properties of milk and milk whey of black and white Holsteinized cows obtained by the rennet coagulation studies in the relationship with the genotypes for beta- and kappa-casein genes. The distribution of alleles for the CSN2 gene in the studied population: A1 – 0,424 and A2 – 0,576. The distribution of alleles for the CSN3 gene: A – 0,754 and B – 0,246. Among the cows studied, most of the animals (55,9 %) are carriers of the A1A2 genotype, 29,7 % of the A2A2 and 14,4 % of the A1A1. Carriers of the AA genotype were 57,6 % of the animals, 35,6 % were AB and only 6,8 % were BB. The whey-to-milk ratio showed reliable differences and trends among the groups of animals of different genotypes by CSN2 and CSN3 genes for the indices of MFF, MFP lactose content, dry matter and casein content, which indicates the influence of genotype on the properties of milk during technological processing. Single-factor analysis of variance showed a significant effect of CSN2 gene genotype on rennet clotting and MFP in milk. Also a significant effect of CSN3 gene has been shown on rennet coagulation of milk, milk yield, MFF, MFP, casein content; in this connection it is the most perspective factor for further study and inclusion in breeding programs in order to increase genetic potential of milk productivity and qualitative composition of milk most suitable for processing in the populations of black and white Holstein breed.