Productive qualities of cows and their relationship depending on the kappa-casein genotype

Abstract

Due to the rapid development of cheese making, questions arise about obtaining milk with the properties necessary for their production, which are determined, among other things, by heredity. There is a need to evaluate cows of different genotypes by kappa-casein to make a decision on their breeding. The purpose of the work is to study the productive qualities of Holstein cows and their relationship depending on the kappa-casein genotype. As a result of the conducted studies, it was found that cows with the kappa-casein BB genotype exceeded their peers from other groups by 452.35 kg (AA genotype) and 291.33 kg (AB genotype) or by 4.2- 2.7% in milk yield for the first lactation.Cows with the kappa-casein genotype AB and BB have stable lactation activity characterized by high milk yields in the second half of lactation, whereas cows with the AA genotype have a decrease in milk yield. Cows with the kappa casein AA and AB genotype have a negative correlation between milk yield and PMF in milk, while they are positive between milk yield and FMF in milk. The correlation coefficient between milk quality indicators – FMF and PMF in cows with the AA and AB genotypes was positive, while in animals with the BB genotype it was low and negative. Thus, it can be said that cows with different kappa-casein genotypes differ in indicators of the relationship between productive traits.