ТРИВАЛІСТЬ ТА ЕФЕКТИВНІСТЬ ГОСПОДАРСЬКОГО ВИКОРИСТАННЯ КОРІВ УКРАЇНСЬКОЇ ЧОРНО-РЯБОЇ МОЛОЧНОЇ ПОРОДИ
Duration of economic use and lifetime productivity of cows determines the overall efficiency of dairy cattle. The main aim was to investigate the efficacy and duration of lifetime use of Ukrainian black and white dairy cows in western Ukraine. Life duration, duration of economic use, age of lactation and lifetime productivity were studied using zootechnical materials accounting. Animals of Ukrainian black and white dairy cattle from the leading farms in the Western Ukraine are characterized by low economic duration of use (3.2-4.3 lactation). Duration of economic use and lifetime productivity of cows is caused by genotype, including their linear identity. The highest lifetime, economic duration of use, number of lactations and productivity were highest in animals of lines Bell 1667366.74, K. Frans 9069, S.T. Rokita 252 803 and M. Chifteyna 95 679. The duration and efficiency of cows use depends on the size of yield in the first lactation. The highest life expectancy, economic use and number of lactations were in cows that had 4000 kg of milk at the first lactation. The highest lifetime productivity was in the cows with 6000-6999 kg of milk at the first lactation. Life milk yield correlated with lifetime, economic duration of use, number of lactations during whole life and yields for each day of life. Positive reliable connection is established between life yields and yields on individual cows lactation. Most animals were culled by reproductive dysfunction (37.5-45.0%) and low productivity (15.8-21.5%).