Milk productivity of black-and-white and Kholmogory cows with different genotypes of kappa-casein

The influence of genotypes for kappa-casein gene on the main indicators of milk productivity in the 1st and 3rd lactation in black-and-white and Kholmogory cows was studied. The genotyping of cows for the CSN3 gene was carried out by the method of DNA diagnostics. Cows of the black-and-white breed with genotype CSN3 BB surpass the group with genotype CSN3 AA and CSN3 AB in the 1st lactation in milk yield by 166-218 and in milk fat yield by 4.9-8.7 kg; for the 3rd lactation 188-298 kg and 7.7-10.2 kg, respectively. At the same time the difference is significant in terms of the mass fraction of protein in milk by 0.06-0.15% (Р