| Popis: |
Serum thyroxine (T4) and triiodothyronine (T3) concentrations were determined twice daily (830h and 16h) in seven primiparous Holstein cows from 4 days prior to (-4, -3, -2, -1) to delivery, on the day of calving, and up to 4 days postpartum (1, 2, 3, 4) by radioirnmunoassay (RIA). Serum thyroid hormone concentrations were higher in the afternoon samples on the first two days of investigation (-4 and -3), hut this circadian rhythm was not maintained. Serum thyroid hormones declined significantly after delivery according to a polynomial regression line (R2=0.967 for T4; R2=0.9216 for T3). Ispitivanje koncentracije tiroksina (T4) i trijodtironina (T3) u krvnom serumu vršena su radioimunološkom (RIA) metodom kod 7 junica Holštajn rase 4 dana pre porođaja (-4, -3, -2, -1), na dan porođaja (0 dan), i posle pqrpdaja (1, 2, 3, 4 dana) uzimanjem dva uzorka krvnog seruma dneyno (u 8 h ujutro i 16h popodne). Koncentracija hormona tireoideje bilaje visa u popodnevnom uzorku u prva dva dana ispitivanja (- 4 i - 3 dana), ali nije ustanovljen jasan cirkadijalni ritam njihove sekrecije. Koncentracija hormonatireoideje opada značajno nakon partusa prateći regresionu polinomsku liniju (R =0.967 za T4; R =0.9216 za Т3). |
