Indicators of cows longevity of Ukrainian Red-and-White dairy breed depending on the share of Holstein breed heredity

With the gradual increase of Holstein breed heredity, the life expectancy of cows and the number of lactations used in the first four groups of crossbreed animals with a blood level from 25 to 62.5% decreased and amounted to 2481 days and 4.7 lactations in IV group cows. Subsequently, with the use of absorbed crossing, there was a noticeable reduction in the duration of crossbred cows using. Thus, animals with a conditional blood level of 75.0% gave way to a group of cows with heredity of 62.5% at 218 days by longevity and 0.6 lactations used (P<0.001). In next-generation animals with Holstein heredity 87.5%, life expectancy and number of lactations compared to the previous (75.0%) decreased by 95 days and 0.3 lactations, respectively. A straight-line relationship was established between the conditional blood level for Holstein breed and milk yield for lifetime. Growth heredity of Holstein breed did not lead to a reduction in lifetime yield in crossbred animals. Thus, group of cows with Holstein blood share of 93.75% gave the highest lifetime yield (30,856 kg) of excess genotypes other groups of cows to 1734-5605 kg of milk with a significant difference in comparison with crossbred genotypes of I-IV groups (P<0.001), V – (P<0.01) and VI – (P<0.05). Thus, the results of researches testified the dependence of lifetime indicators of cows dairy productivity of Ukrainian Red-and-White dairy breed on Holstein heredity, especially during absorption crossbreeding. With escalating of Holstein heredity, lifetime yield of milk and milk fat of cows increased with constant fat content, but the longevity and number of used lactations thus decreased.