The objective was to establish the thermal comfort zone for Santa Ines sheep by comparing the physiological responses at different options of temperatures in bioclimatic chamber. The experiment lasted 71 days and was conducted with the use of seven Santa Ines lambs per treatment. The treatments were temperature ranges of 10, 15, 20, 25, 30, 35 and 40ºC with tree replicates (exposure days) and a five-day interval. The experimental design was completely randomized. Meteorological data collected were: dry bulb temperature; wet bulb temperature and black globe temperature. Physiological data analyzed were: respiratory rate, heart rate, rectal temperature, tympanic temperature, sweating rate and blood pressure. The physiological mechanisms of heat dissipation are shown to be effective in maintaining the homeothermy of the animals studied at all temperatures. The temperature of 25ºC can be determined as the thermal comfort zone for Santa Ines lambs in an environment with relative humidity of 65%.
bioclimatic chamber; heat stress; lambs
