COMPARISON OF SEX HORMONES LEVELS IN FEMALE REINDEER DURING ANESTRUS AND THE BREEDING PERIOD

Reindeer husbandry is a historically established main branch of animal husbandry in the northern regions of the Russian Federation. Despite the active of domestic reindeer breeding within the northern latitudes of our country, the features of the biological processes of this animal species remain incompletely understood. The importance is a detailed study the reproductive system physiology, which is relevant in light of the prospects for introducing assisted reproductive technologies into reindeer husbandry practice in order to intensify the selection process. Assisted reproductive technologies in reindeer husbandry are currently not used even in breeding herds due to the low level of development, although their introduction can significantly reduce the time and financial costs of selection and breeding work carried out to improve the productive qualities of domestic reindeer breeds. In mammals, the sexual process is under the complex subordinate control of neurohumoral mechanisms, which are based on changes in hormonal status, that is, the levels and ratios of the hormones in accordance with the physiological cycle. Reindeer are the least studied productive farm animals in terms of reproduction. The current trend is to study the hormonal regulation of reproductive processes in female reindeer in different physiological states, such as anestrus, rut, pregnancy, and the post-calving period. We studied the concentration of estradiol, progesterone, and luteinizing hormone (LH) in the blood of female reindeer before the rut (early summer, early autumn, and at the beginning of the rut). The levels of hormones were determined using enzyme immunoassay. The study determined the level hormones in physiologically healthy female domestic reindeer in the early summer and early autumn periods and at the beginning of the rut. The results obtained showed a statistically significant decrease in the concentration of progesterone and estradiol. A decrease in LH was recorded in the warm period with an increase towards the breeding period.

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