ENDOCRINE AND METABOLIC PROFILE IN HOLSTEIN AND RED HOLSTEIN HEIFERS DURING PERIPARTAL PERIOD

The aim of this stady was to examine the relationship between triiodothyronine (T-3), thyroxin (T-4), insulin-like growth factor-I (IGF-I) and blood serum liver function biomarkers concentrations in Holstein and Red Holstein heifers during the peripartal period. In the first experimental group (I) were heifers of Holstein Friesian breed (n=10), and in the second experimental group (II) were Red Holstein heifers (n=10). Blood samples were taken from the vena coccygea three times during the short peripartal period (5 days before delivery, at delivery and 5 days after delivery), and blood serum samples were separated after spontaneous coagulation. Blood serum T-3, T-4 and IGF-I concentrations were determinated using radioimmunoassay (RIA). Blood serum concentrations of glucose (G), total protein (TP), albumin, (Alb), urea, total bilirubin (tBil) and aspartate aminotrasferase (AST) were determined using commercial ELISA kits. The statistical significance between means was determined using Student t-test. Blood serum T-3 concentration in Group II was significantly lower after delivery, and T-4 concentration was significantly higher before delivery (p < 0.05), compared to Group I. Mean blood serum IGF-I concentrations between the two experimental groups were not significantly different at all time intervals. Relationships between the determined hormones showed a median positive correlation between T-3, and T-4 (r=0.74) in Group land highly positive correlation in Group II (r=0.81). Blood serum thyroid gland hormones and IGF-I concentrations in healthy heifers during peripartal period vary considerably, the lowest values being determined immediately after calving in both experimental groups. Blood serum G, TP Alb and urea concentrations were significantly higher in Group I at all investigated time intervals. Blood serum tBil concentration was significantly higher after partus in Group I (11.02 +/- 3.33: 8.49 +/- 3.35 mu mol/L, Group I vs. II, respectively), and AST activity was not significantly different at all intervals.