Responses of shorn and full-fleeced lambs given two levels of feed intake and exposed to warm and cold temperatures.

Studies on the effect of fleece length (5 and 85 mm) and feed intake (1 and 2 kg/day) were conducted in 9- to 10-month-old wether lambs kept at 2 environmental temperatures (-12.3 and 17.8 C). Digestion coefficients were lower (P less than 0.05) at the high level of intake and in cold-exposed lambs. Rectal temperature was lower (P less than 0.05) in lambs kept at - 12.3 C. Respiration rate increased (P less than 0.05) with increasing environmental temperature and higher feed consumption. Blood glucose and plasma urea nitrogen concentrations were not affected by feed intake level or fleece length. Glucose was higher (P less than 0.05) and plasma was lower (P less than 0.05) in lambs at low temperatures. Serum-free fatty acids were increased (P less than 0.05) in lambs given the low feeding level and kept at the low temperature. Plasma thyroxine and protein-bound iodine concentrations were lower (P less than 0.10) in full-fleeced lambs and were higher (P less than 0.05) at the low temperature.