The functional state of the thyroid gland in the presence of the pathology of the cows' reproductive organs in the Far North

The study has been undertaken on the territory of the Murmansk region where the natural and climatic conditions cause iodine deficiency in the environment, resulting in a decreased thyroid gland function. As a part of the research, the functional activity of the thyroid gland of the cows with the pathology of reproductive organs has been studied. At a local dairy cattle breeding enterprise in the town Apatity some cases of gynecological diseases, particularly follicular ovarian cysts have been registered. The development of cystic degeneration can be caused by various disorders of neuroendocrine regulation, such as high milk production in the milk period of cows, inflammation in the genitals, feeding errors, hypodynamia, and hormone overdose during therapy as well as ovarian dysfunction. It is known that the function of the thyroid gland is closely connected with the hypothalamus - hypophysis - ovaries system. Thyroid gland hormones stimulate the function of the central nervous system, regulate the metabolism and have a positive effect on the growth, development and reproduction of cows. Thus, the function of the thyroid gland has a pronounced impact on the state of the reproductive system. In this regard, a histological examination of the thyroid glands obtained after the slaughter of defective animals has been carried out. A micrometric analysis of the thyroid gland of cows of reproductive age in groups separated by the presence, or absence of follicular ovarian cysts has been performed. The peculiarities of the micrometric thyroid gland structure (the inner diameter of the follicles, the thickness of the thyroid epithelium) have been studied; a strong inverse relationship between the indicators studied has been identified. It has been found that there is no significant difference in the functional activity of the thyroid gland of the cows with cystic regeneration and without it.