There is a close functional relationship between the ovaries and thyroid gland (thyroid). Thyroid hormones (TH) play an important role in the regulation of various physiological and cellular functions, including growth, development and metabolism in general. Thyroid secretes several forms TG : thyroxin (T4) , triiodothyronin (T3 ) and reverse triiodothyronin (zT3).

Considering the literature data and the results of previous own studies that show significant hemostatic, metabolic, inflammatory disorders in cows purulent necrotic limb disorders in the area and the existence of a common mechanism in the pathogenesis of orthopedic and obstetric diseases, the question of the nature and significance of their dystyreoz associated manifestations.

The aim of the study was to determine the dynamics of thyroid hormones in the blood and tyrotropin high-yielding cows during pregnancy and the postpartum period and establishing the nature of thyroid dysfunction for orthopedic and obstetric diseases.

Research materials served as a high-performance Ukrainian black and white Holstein dairy breed cow’s 3–7 years age. In the serum of cow’s by enzyme immunoassay (ELISA test) determined the content of free thyroxin, free triiodothyronin, and thyrotropin .

We found that during physiological pregnancy there is likely (p<0,001) increase in T₃. From the third month of pregnancy until the end of its concentration increased from 5,47 to 8,10 pg/ml, 48 %. Special Period was the fifth month, which was characterized by decreased levels of the hormone. As for thyroxin, it should be noted that similar dynamics was observed. In the third and seventh month of pregnancy its values are the same – 2,41 ng/DL, and in the fifth and ninth – it level dropped to 1,68 and 1,16 ng/DL, respectively. In our opinion, this was due to the activation of thyroxin deiodization followed by transformation into triiodothyronin as a more active form, and for increasing concentrations of T₃. At the same time, the tyrotropin concentration gradually increased from 0,15 to 0,23 mkIU/ml during the first half of pregnancy significantly increased (2,7 fold, p<0,0001) – in the seventh and reached a peak of 1,51±0,15 mkIU / ml in nine months. Thus, during pregnancy there is a growing pituitary stimulation of the thyroid gland, a gradual increase in the level of triiodothyronin in half and reducing the concentration of thyroxin twice. Such dynamics can be explained by activation of thyroid function corresponding to an increase in consumption, protein synthesis, metabolism, simultaneous to the development and needs of the fetus.

In the early postnatal period marked a dramatic decrease of T3 to 4,48 pg/ml, which is 1,8 times less than for families. TSH level was also significantly (p<0.001) less than 6 times (0,25 vs. 1,51 in the ninth month of pregnancy), and T₄ concentration remained almost unchanged – 1,46 ng/DL. This hormonal profile indicates a pituitary suppression is possible functionally linked with the physiological decline synthesis follicle stimulating and luteinizing hormones and increased glucocorticoid and adrenaline series (mechanisms of stress for families) [1, 6]. Hypothetically, let us assume that the suppressive effect may have during this period as somatotropin and prolactin.

On the 25th day after birth TSH synthesis increased (p<0,05) to 0,42 mkMO/ml, which resulted in a significant increase in the concentration of triiodothyronine at 26%. 60–65th days was recorded even greater stimulation of the pituitary thyroid as both background contents TSH increase to 0,68 mkIU/ml and increased levels of T3 to 6,76 pg/ml. As for the concentration of T4, then it was characterized by unreliable indicators of change within 1,46–1,79 ng/DL during the two-month period after birth. Thus, in the first 5–10 days after birth observed a significant reduction in the functional activity of the thyroid, and the 15–20th day, amid pituitary stimulation, the level of free triiodothyronine gradually increased in 1.6 times from 60 to 65th days. This dynamic indicates a close functional relationship with thyroid lactation regulatory process and the restoration of ovarian cycle.

For obstetrical and gynecological pathology marked by certain changes in thyroid support. Thus, the most striking was significant (p<0,05; 0,01) decrease in the concentration of thyroxin in cattle manure and detention of postpartum merits – up to 3,45 and 3,22 pg/ml, respectively. Over the course of chronic inflammation of the uterus decrease its level continued and reached 2,70 pg/ml, which is 60 % lower than in cows with normal puerperal period 15–20th day after birth.

Ovarian dysfunction was accompanied by a decrease in the number of triiodothyronin and 1,8 times tyrotropin half. For purulent necrotic lesions in the region of the fingers characteristic was 1,4–1,7 times reduction in the content of triiodothyronin during seventh to ninth months of pregnancy and increasing concentrations of thyroxin 1,5 times against the background of low tyrotropin three times in nine months. Postpartum period of cows ran a high concentration of thyroxin in the blood and significantly reduced – tyrotropin and triiodothyronin.

According to an associate of orthopedic pathology and delay placenta, postpartum metrits, ovarian dysfunction in cattle showed a significant decrease of triiodothyronin on the background of increasing tyrotropin.

Key words: cow, thyroxin, triiodothyronin, tyrotropin, pregnancy, post-natal, obstetric disease, ovarian dysfunction, purulent-necrotic lesions in the region of the fingers.