Dynamics of thyroid gland morphometric indicators in pigs in postnatal ontogenesis

The purpose of research is the study of the dynamics of morphometric parameters of the thyroid gland of pigs in postnatal ontogenesis. Studies are conducted in the Stavropol Region. The object of the study was the thyroid gland of the pigs of a large white breed aged 1 day (newborns), 3, 6, 9 and 12 months. All animals were female, three individuals in each group. It is established that the area of follicles of the thyroid gland of the pigs of a large white breed increases from birth to three months, and decreases by 12 months. The maximum average value of this indicator (5178.00 ± 569.70 μm2) is observed in nine months, minimal (1213.00 ± 154.00 μm2) – in newborn pigs. The thyrocytes area of pigs increases from six to nine months of age. The minimum average values (45.54 ± 0.56 μm2) were noted at birth, the maximum (57.07 ± 0.78 μm2) at 12 months. The area of thyrocyte nuclei remains relatively stable until the age of nine months, increasing by the ninth month, reaching the maximum average value (37.50 ± 0.38 μm2). However, by the age of 12 months, this parameter decreases to average values among all studied groups. The minimum average value of the area of the nuclei of thyrocytes is observed at six months. The nuclear-cytoplasmic ratio of thyrocytes in pigs at six months decreased, and at nine months, on the contrary, in-creased to the maximum average value (0.68 ± 0.004 ed). The minimum average value of the NCR (0.52 ± 0.004 units) is observed at the age of 12 months, upon reaching which this parameter decreases.