Effects of high temperature on body temperature and hormonal adjustments in piglets

Abstract

Effects of a high (33 °C) or thermoneutral (23 °) temperature on body temperature and endocrine parameters were studied in weaned piglets. Rectal and skin temperatures were measured in four ad libitum fed animals per temperature during three weeks. After this acclimation period, 11 blood samples were withdrawn on a 24-h period. Over the acclimation period, rectal and skin temperatures were 0.6 and 2.9 °C higher, respectively, at 33 °C than at 23 °C (P < 0.01), this change occurring from the 1st day at 23 or 33 °C. A tendency of serum leptin concentrations to be lower after meals at 33 °C than at 23 °C was also displayed (P = 0.09). Plasmatic concentrations in Insulin-like growth factor I and thyroxine were decreased at 33 °C relative to 23 °C (P < 0.01 and P < 0.06, respectively), and triiodothyronine concentrations tended to be lower at 33 °C than at 23 °C (P = 0.1), which could account for the lower heat production and growth observed in pigs exposed to high temperatures.