Body heat content, heat production and respiration in sheep exposed to intermittent cold

Lee, S. R.; Sasaki, Y.

doi:1994.7.3.357

Article

Ruminant Nutrition and Forage Utilization

Asian-Australasian Journal of Animal Sciences 1994;7(3): 357-362.
https://doi.org/10.5713/ajas.1994.357 Published online September 1, 1994.

Body heat content, heat production and respiration in sheep exposed to intermittent cold

S. R. Lee, Y. Sasaki

Abstract

Five adult sheep were exposed to intermittent cold for 12 h (18:00-06:00) at an air temperature of 5 1째C followed by 12 h (06:00-18:00) at 25 2째C over a period of 8 days continuously. Carotid artery blood (Tc), mean skin (Ts) and mean body (Tb = 0.86 Tc + 0.14 Ts) temperatures, heat production rate (HP), respiratory evaporative heat loss, respiration rate (RR) and volume were measured before and after exposure. Tc during the 12 h cold period of intermittent cold exposure was similar to that during the corresponding period in the warm environment, while Tc in the 25째C of intermittent cold was higher (p<0.05) than that in the corresponding period in the warm environment. Ts during the cold period markedly decreased (p<0.001) by about 9째C when compared with that in the corresponding time period in the warm environment, while Ts during the 25째C period of intermittent cold recovered to a similar level to that in the warm environment. Tb was lower (p<0.001) during the cold period of intermittent cold, whereas a slight increase in Tb during the 25째C period of intermittent cold was significant (p<0.05) when compared with the value during the similar period in the warm environment. HP was greatly increased (p<0.001) by cold exposure, followed by an immediate decrease during the first one hour of the 12 h warm period, reaching a similar level to that in the warm environment. A lower (p<0.05) RR was observed during both the cold and 25째C period of intermittent cold than during the corresponding periods in the warm environment. The results of the present investigation clearly show that the body temperature of sheep increased during a 12 h warm period following 12 h of exposure to cold. These results suggest that during a warm period of an intermittent cold exposure cycle, heat could be shored in the animal body.

Keywords: Sheep; Intermittent Cold Exposure; Body Temperature; Body Heat Content; Heat Production; Respiration