Reproductive ability and milk productivity of cows depending on breeding value of their progenitors

Abstract

The influence of bullock`s different breeding value for reproductive ability and milk production of their  daughters were investigated. Established that the age of first productive insemination of heifers Ukrainian black spotted milk breed, was 17.5–18.6 months and age of first calving – 26.6–27.8 months. Heifers` live weight at the first insemination was 361.4–407.1 kg. During first lactation the highest productivity had daughters from parents with breeding value by milk yield more than 801 kg. In the first lactation wasn’t found significant difference in duration service-period and interparturition-period for cows derived from progenitors with different breeding value. In the second lactation best indexes in duration service-period and interparturition-period for cows derived from progenitors with breeding value by milk yield 601–800 kg and more than 801 kg. In the third, the highest lactation, these indexes were best for cows derived from progenitors with breeding value by milk yield 601–800 kg. The difference in milk yield during first lactation between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value 401–600 kg was 292 kg. The difference in milk yield between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value  with breeding value 601–800 kg  was 660.3 kg. The difference in milk yield between heifers received from progenitors with breeding value by milk yield less than 200 kg and heifers from bullock`s  with breeding value more than 801 kg was  920.8 kg In the second lactation this difference was 589.8 (Р < 0.001), 841.5 (Р < 0.001) і 894.4 (Р < 0.001) kg of milk, in the third, the highest lactation – 754.5 (Р < 0.001), 951.8 (Р < 0.001) і 1335.7 кг (Р < 0.001).