The Effect of Dietary Fat Level on Heat Prostration of Broilers

Three trials were conducted to study the effect of dietary fat level on mortality that was due to heat prostration in 8-week-old male broilers. The four diets contained 1, 3, 7 and 10 percent added animal fat and were fed ad libitum for the 4- to 8-week experimental period. At 8 weeks of age, the dry-bulb temperature was increased from 21.1° C. with a dew point temperature of 10.0° C. to 40.6° C. over 6 hours, with a dewpoint temperature of 23.9° C. The temperature was held at 40.6° C. for 2 hours, then decreased to 26.7° C. over 30 minutes. Mortality that was due to heat prostration was recorded at 30-minute intervals during the stress test. The results obtained indicate that the dietary level of animal fat did not affect mortality due to heat prostration. This finding is significant since more concentrated rations are sometimes fed to commercial broilers during the summer in an attempt to improve growth and feed utilization.