CONCENTRATION OF STEROID AND GONADOTROPIC HORMONES IN THE BLOOD SERUM OF FEMALE REINDEER IN THE LATE PREMAILING AND EARLY POSTPARTUM PERIODS

Despite the fact that reindeer (Rangifer tarandus) are an important commercial species for providing food for the population in difficult living conditions, they are currently poorly studied due to the complexity of conducting research. This is especially true for physiological characteristics associated with reproduction, the gaps in which complicate the implementation of modern assisted reproductive technologies. Deep knowledge of endogenous hormonal regulation in different physiological periods of female reindeer could allow us to manage the reproductive function. The work is devoted to the analysis of concentrations of steroid hormones 17β - estradiol and progesterone, as well as gonadotropins - follicle-stimulating and luteinizing hormones of females during the breeding season. The object of the study were female (female) reindeer (n = 31). The habitat is a reindeer farm in the north of Western Siberia, in the Yamalo-Nenets Autonomous Okrug of Russia. The total sample was divided into two groups: group 1 (n=16) did not calve and group 2 (n=15) did. The hormone levels in the blood serum were determined using enzyme immunoassay. The results of the studies show that in the group of does in the late calving period, the concentrations of estradiol and progesterone were significantly higher (p<0.01) compared to the group of does after calving. At the same time, a tendency towards an increase in follicle-stimulating hormone can be noted after calving. A negative correlation was recorded in the case of progesterone and luteinizing hormone in the group of does in the early calving period (r=-0.735, p<0.01). A positive correlation was found between follicle-stimulating and luteinizing hormones (r=0.811, p<0.01). In the group of animals in the late calving period, a positive correlation was found between progesterone and estradiol (r=0.641, p<0.01). The results obtained suggest that in female reindeer, the resumption of sexual cycles occurs according to a similar hormonal scenario, in which the level of steroid hormones decreases after calving, and the concentration of gonadotropic hormones, on the contrary, gradually increases with higher FSH dynamics, compared to LH.

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