УДК 636.2.082.2.034
P. S. Galushina, O. A. Bykova
Summary Dairy cattle breeding is a priority area of agriculture worldwide, and indicators of dairy productivity for cows of specialized breeds are impressive, reaching up to 25,000 kilograms of milk per lactation. Currently, farms in the country continue to use purebred Holstein bulls for breeding, both domestic and imported. To date, most livestock in agricultural enterprises have a bloodline that is over 87.5% Holstein, making it possible to classify them as Holsteins. The study involved three groups of 25 cows, divided by their origin: descendants of bulls from De Su (USA), Sayan (Denmark), and Tuareg (Germany). These bulls are all purebred Holsteins from different lines. The daughters of the Sayan bull produced the most milk per lactation (7,845 kilograms), while the daughters of Tuareg produced the least (7,456 kilograms).. In terms of the mass fraction of fat and protein in milk, the offspring of the De Su bull showed the best results (4.34% and 3.15%, respectively), while the descendants of the Sayan bull led in terms of nutrient output, producing 560 kg of fat and protein per lactation. The length of lactation in all groups exceeded 305 days, with the minimum service period of 123 days for the offspring of Tuareg bulls and the maximum of 184 days for those of De Su. The coefficient of fertility (CFS) ranged from 0,91 to 0,94, confirming the efficiency of reproduction and productivity of these groups. The study confirms the high performance of the Holstein breed and its breeding bulls in terms of milk yield and quality.
Keywords: holstein breed, breeding bulls, milk yield, milk yield, mass fraction of fat, mass fraction of protein, quantity of milk fat and protein, service period, reproduction.
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