STUDIES ON THE R E L A T I O N S H I P BETWEEN T H Y R O I D FUNCTION, COLD A C C L I M A T I O N A N D R E T E N T I O N T I M E OF D I G E S T A IN SHEEP 1 ,2
University o f Alberta 3, Edmonton, T6G 2E3, Canada
SUMMARY The effects of ambient temperature (22 to 55 C vs 2 to 5 C) and injection of triiodothyronine (T3; O, .125 or .25 mg T3/day) on apparent digestibility, oxygen consumption, concentration of thyroid hormones in plasma, and mean retention times of digesta in the reticu!o-rumen, hind gut and total tract of sheep given brome grass (Bromus inermis) pellets were studied in two experiments in order to determine whether T3 was a mediator causing the decreased retention time observed in cold-exposed sheep. In thyroid-intact sheep, both exposure to cold and injection of T3 resulted in decreased (P
University o f Alberta 3, Edmonton, T6G 2E3, Canada
SUMMARY The effects of ambient temperature (22 to 55 C vs 2 to 5 C) and injection of triiodothyronine (T3; O, .125 or .25 mg T3/day) on apparent digestibility, oxygen consumption, concentration of thyroid hormones in plasma, and mean retention times of digesta in the reticu!o-rumen, hind gut and total tract of sheep given brome grass (Bromus inermis) pellets were studied in two experiments in order to determine whether T3 was a mediator causing the decreased retention time observed in cold-exposed sheep. In thyroid-intact sheep, both exposure to cold and injection of T3 resulted in decreased (P
