Milk productivity of cows with different CSN3 and DGAT1 genotypes depending on the age of the first calving

The cows were divided into 3 groups depending on the size of the feature to study the dependence of milk production of fresh cows of different genotypes on kappa-casein (CSN3) and diacylglycerol O-acyltransferase (DGAT1) on the age of the first calving. Group I included cows, that had an age of first calving less than 26.0 months, group II - 26.1-28.0 months, group III - more than 28.1 months. It was found that with increase in the age of the first calving, milk yield, milk fat and protein yield, milk yield index of experimental iirst-calves increased, with the greatest and reliable difference between groups and high productivity indicators were typical for fresh cows of CSN3AB, CSN3BB, DGAT1ak genotype. "