The effect of water restriction on some physiological responses of steers during enforced exercise in a warm environment

Abstract

Two groups of steers, accustomed to drinking either once daily in the afternoon every other day or twice daily, were subjected to enforced exercise in a warm environment for four consecutive days. Animals in the restricted watering group were exercised both 42 h (days 1 and 3) and 18 h (days 2 and 4) after having access to water. Control animals watered twice daily commenced exercise 2 h after watering on all four days. On days 1 and 3, the restricted group exhibited higher rectal temperatures and lower respiratory rates with exercise than the control group. On days 2 and 4, restricted animals displayed both lower rectal temperatures and respiratory rates than control animals. Measurements of sweating rate and feed intake are reported. These data suggest that neither evaporative heat loss from the skin nor body heat production was implicated in the lower rectal temperature response of restricted animals on days 2 and 4. It is suggested that the lower rectal temperatures of restricted animals during exercise on days 2 and 4 may be related to their greater water intakes at the afternoon watering on days 1 and 3.