SELECTIVE BREEDING OF HIGHLY PRODUCTIVE COWS
Highly productive animals are the basis of profitability and competitiveness of dairy production. Highly productive animals indicate the potential for productivity and play an important role in the formation of families and lines. It was found that in the selective breeding of highly productive Kostroma cows, the progress in terms of milk yield and fat content percentage was mainly achieved through the use of bulls of related groups as Meridian 90827, Master 106902 and Ladok KTKS-253 line. The analysis of the genealogical origin showed that most of high yielding cows (87%) had been obtained by means of line-crossing and only 13% had been bred by intra-line selection. The cross-bred cows produced more milk; the difference in milk production was 261 kg and 142 kg during the third and the highest lactation, respectively. To improve the genetic potential of the Kostroma breed at stud breeding, the priority should be given to the cows with the ЕАВ-alleles of B-system blood type: I1G’G’’, B1G2KE’1F’2O’ and O’, as they mark the genotypes of the cows with high level milk production.