Effects of environmental temperature on heat production and its energy cost for thermoregulation in dairy heifers

Purwanto, B. P.; Harada, M.; Yamamoto, S.

doi:1994.7.2.179

Article

Animal Reproduction and Physiology

Asian-Australasian Journal of Animal Sciences 1994;7(2): 179-182.
https://doi.org/10.5713/ajas.1994.179 Published online June 1, 1994.

Effects of environmental temperature on heat production and its energy cost for thermoregulation in dairy heifers

B. P. Purwanto, M. Harada, S. Yamamoto

Abstract

A study was conducted using four dairy heifers to determine the effect of 10, 20 and 30째C environmental temperatures on the physiological responses and heat production, at a fixed level of TDN intake (60.5 g/kg0.75 d). The analysis showed significant affects of environmental temperature on respiration rate (RR), mean body temperature (Tb), changes in body heat storage (S) and heat production (HP). The HP at 20째C was almost the same as at 10째C, but the HP at 30째C was 11% higher than at 10째C. A tendency for an elongation of standing time (ST) with the increase in environmental temperature was also observed. These results suggest that the increase in energy cost of elongation of ST (9.2 kJ/kg0.75 d) and 1.3째C increase in Tb (17.3 kJ/ kg0.75 d).

Keywords: Environmental Temperature; Heat Production; Standing Time; Mean Body Temperature; Dairy Heifer