Clinical and experimental substantiation of the use of reduced concentrations of FSH during superovulation in highly productive cows

The purpose of the studies was to substantiate the use of reduced concentrations of follicle-stimulating hormone to induce superovulation in highly productive cows and heifers. The research was carried out in one of the farms in the Leningrad region. After analyzing breeding cards and based on ultrasound visualization of the reproductive organs, promising animal embryo donors were selected - cows after the first calving and heifers that had reached physiological maturity, Holstein breed. According to the principle of analogues, groups of experimental animals Ⅰ and Ⅱ were formed, which included cows, and groups Ⅲ and Ⅳ, which included heifers, eight and six animals each, respectively. To induce multiple ovulation, hormonal treatment regimens were used, presented in Table 1. Hormonal treatment regimens were compiled in accordance with methodological recommendations on the procedure and conditions for applying the method of cattle embryo transplantation, as well as in accordance with the results of previously conducted studies and analysis of literary sources. As a result of the studies, it was established that all experimental animals responded equally to the hormonal regimen recommended by the manufacturer of exogenous gonadotropins and the experimental regimen, with a reduced concentration of the latter. It was revealed that there were no significant differences in the number of corpora lutea in the groups of cows and heifers when using a standard scheme for stimulating polyovulation and with a reduced content of follicle-stimulating hormone. There was also no difference between the experimental groups of cows and heifers in the number of embryos obtained. Analyzing the data obtained, we can conclude that it is advisable to use reduced concentrations of pituitary gonadotropins to stimulate multiple ovulation in highly productive cows and heifers.