LIVE WEIGHT OF UKRAINIAN BLACK-AND-WHITE DAIRY HEIFERS DEPENDING ON THE SIRE’S ORIGIN AND COUNTRY OF BREEDING

The article presents the results of a retrospective study on the dynamics of live weight in Ukrainian Black-and-White dairy heifers over a ten-year period. It was found that the heifers of this breed demonstrated relatively high live weight indicators at all studied age stages, reaching 410.2 kg at 18 months of age. The development of this trait was significantly influenced by the sires and the bulls’ country of origin. The daughters of the bull S. Aristotle 63026616 had the highest live weight at 18 months (431.1 kg) and the highest average daily gain over the entire rearing period (0–18 months), amounting to 719.7 g. In most cases, they significantly outperformed the offspring of other bulls. Notably, the offspring of sires of Russian origin showed superior weight gain across most age periods. At 6, 12, and 18 months of age, they exceeded the live weight of the progeny of Dutch, Hungarian, and German bulls by 10.8–37.1 kg (P < 0.05–0.001), and by 22.6–66.1 g (P < 0.05–0.001) in average daily gain from birth to 18 months of age.