THE EFFECT OF FEED-INTAKE ON BODY-TEMPERATURE AND WATER-CONSUMPTION OF MALE BROILERS DURING HEAT EXPOSURE

Two trials were conducted to study the effect of feed intake on rectal temperature and water consumption of acclimated and unacclimated broilers during heat exposure. Male broiler chicks, 100 per trial, were raised as one group to 29 days for Trial 1 and 36 days for Trial 2. The birds were moved to environmental chambers and 50 per trial were acclimated by being subjected to 3 consecutive days of 24 C, 35 C, 24 C cyclic temperature. After acclimation, the birds were exposed to a linear change in temperature from 24 to 41 C over 3 h with a constant 10 C dewpoint, starting at 0800 h on Day 34 for Trial 1 and on Day 41 for Trial 2. The feeding schedule for the day of the heat exposure was as follows. For the feed group, feed was removed from the birds at 0400 h and placed back at 0700 h. For the no feed group, feed was removed at 0700 h. At 0800 h, feed was removed from all birds but water was accessible throughout the heat exposure. Acclimated and unacclimated birds given access to feed for 1 h before a heat exposure consumed 60 and 50 mL of water per broiler, respectively, during the heat exposure. However, for broilers not receiving feed, the water consumption was 58 and 30 mL per broiler, respectively. Acclimated and unacclimated broilers given access to feed had similar body temperatures, but the acclimated broilers not receiving feed had a significantly lower ending rectal temperature than the unacclimated group.