THE INFLUENCE OF GENOTYPE ON REPRODUCTIVE ABILITY OF ANIMALS
Ukrainian Black-Spotted Dairy breed for a long period was formed and improved through the use of Holstein bulls-sires, leading to an increase in the animal genotype of heredity proportion of improved breed. Research conducted on cows of different genotypes of the above mentioned breeds, which were obtained by absorbing crossing of Black-Spotted females with Holstein sires. It was formed 5 groups of animals depending on the share of inheritance Holsteins: I group - Holstein inheritance share of 50 %, II group - 75 %, III group - 87.5 %; IV group - 93.75 % and V group - 100 % (pure-bred Holstein). We have done the search of the influence of conditional portion of Holstein blood on the indices of reproductive ability of animals: age of the first insemination and calving, gestation length, service and between-calving periods, the rate of reproductive capacity, index of the fertility, index of insemination, fertilizing ability of heifers and firstborn cows after the first, second third and more insemination and output of calves per 100 cows. It was established that with the growing portion of the inheritance of Holstein breed, age of the first insemination of heifers and cows calving, the coefficient of animal reproductive capacity, the output of calves per 100 cows and heifers and first-born cows fertility after the first insemination is reduced, and the duration of the service periods and between-calving period and index of animal insemination are increasing. It should be noted that the percentage of the influence of genotype on indices of reproductive ability of animals thus was not high, but in most cases it was probable and ranged 0.19-4.67 %. Genotype had the highest impact on the duration of gestation in heifers, and the lowest - on the fertility index.