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

As far as black-and-white cows give milk with low protein level and poor technological properties decision to investigate genetic variants of kappa-casein of the animals was made. It was found that cows with BB genotype of kappa-casein are superior to cows with genotype AA on milk yields, protein content in milk and milk fat and protein yields during the first three lactations. Cows with genotypes AB occupy intermediate position as far as productivity is concerned.