Ovarian response to different doses of follicle-stimulating hormone in donor cows with different levels of anti-Müllerian hormone

Variability of response to stimulation of superovulation is one of the biggest problems of industrial production of bovine embryos. Given the importance of the effect of the hormonal stimulation scheme and the role of anti-Müllerian hormone as a predictor of ovarian response to stimulation, the aim of the study was to determine the effect of the dose of follicle-stimulating hormone on stimulation of superovulation in donor cows with different concentrations of anti-Müllerian hormone in the blood serum. All animals admitted to the experiment were randomly divided into 3 groups based on the concentration of anti-Müllerian hormone in the blood serum: the first group – < 0.1 ng/cm3 (low level); the second group – 0.1–0.25 ng/cm3 (medium level); the third group – > 0.25 ng/cm3 (high level) and their estrus cycles were synchronized. Before stimulation of superovulation, each group of donor cows, formed on the basis of the level of anti-Müllerian hormone in blood serum, was again divided into 3 groups depending on the dose of follicle-stimulating hormone administered to the cows: 800 IU (reduced dose of follicle-stimulating hormone); 1000 IU (medium dose recommended by the manufacturer); 1500 MO (increased). The control group consisted of animals with a medium level of anti-Müllerian hormone with a dose of follicle-stimulating hormone of 1000 IU. Differences between groups were evaluated by counting the corpora lutea, the total number of flushed embryos and the quality assessment of the latter. It was found that the number of corpora lutea and flushed embryos increased proportionally with the concentration of anti-Müllerian hormone in the studied animals, regardless of the dose of follicle-stimulating hormone. A decrease in the dose of follicle-stimulating hormone led to a decrease in the studied indicators in all groups. While increasing the dose of follicle-stimulating hormone, some differences were noted. Thus, in groups of animals with a low and medium level of anti-Müllerian hormone, a decrease in all studied indicators was observed, while with a high level, a significant increase in the number of corpora lutea and the total number of flushed embryos was observed against the background of a sharp decrease in the quality of the latter. In summary, measuring the concentration of anti-Müllerian hormone in the blood serum of donor cows allows one to predict the number of embryos obtained after stimulation. A decrease in the dose of follicle-stimulating hormone led to a decrease in the studied indicators in all the studied groups, while an increase led to a significant decrease in the quality of the obtained embryos, compared to the control group.