FEATURES OF THE LEVELS OF SEX HORMONES IN FEMALE REINDEER (RANGIFER TARANDUS) AT DIFFERENT STAGES OF THE ESTROUS CYCLE

Reindeer (Rangifer tarandus) are a polycyclic animal species with a limited breeding season. Although the main reproductive season for reindeer occurs in autumn, the onset of this period varies even within one geographical area, which is due to feeding factors related to the fatness of animals, as well as temperature, light and other climatic conditions. Therefore, a thorough understanding of the female reindeer reproductive cycles is important for managing reproductive processes, including through assisted reproductive technologies, and increasing the productivity of populations. Hormone levels is a critical aspect in the practice of artificial insemination of animals, since hormonal status has a significant impact on reproductive functions. The aim of our study is to study the hormones concentration: estradiol, progesterone, luteinizing hormone (LH) - in the blood of female reindeer in summer and autumn. The object of the study were clinically healthy female domestic reindeer (n = 3), that live in Pushkin. Blood was taken from June to October, the time interval between blood sampling was on average 1 week. The level of hormones was determined using enzyme immunoassay. Based on changes in LH and progesterone levels, the estrus cycles in the studied animals occurred from July to late October. The dynamics of changes in LH levels at the beginning of the rut season differed in all three animals. In all animals, cyclic increases in progesterone were observed on average every 14 days with the onset of the rut season. All the studied hormones in reindeer female demonstrated moderate and weak reliable correlations.

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