Plasma concentrations of insulin-like growth factor, triiodothyronine, thyroxine, and insulin in cows during different physiological states

Aim. To investigate the plasma concentrations of insulin-like growth factor (IGF, somatomedin C), triiodothyronine, thyroxine and insulin in cows during prepartum and postpartum periods. Methods. Enzyme- linked immunosorbent assay, clinical and statistical methods. Results. It was demonstrated that the plasma concentration of IGF, triiodothyronine, thyroxine, and insulin is lower in postpartum cows compared to the interlactation ones. Strong positive correlation dependence (r = 0.7) between the levels of thyroxine and somatomedin C was found on the 2 nd –4 th day after calving. The plasma concentration of all the investigated hormones increased in cows on the 10-14 th day of postpartum period and remained stable until days 30–40. Strong correlation dependence between the levels of somatomedin C and insulin (r = 0.7) was found on the 10- 14 th day of the postpartum period. Conclusions. It was determined that somatomedin C is one of the energetic balance regulators in dairy cows.