The effect of environmental temperature on growth and feed conversion of broilers to 21 days of age.

Temperature during rearing is a major factor in production efficiency for broilers. The objective of this research was to determine the effect of five temperature regimens on the growth, feed conversion, and mortality of broilers to 21 d of age. This information is needed to select the most profitable conditions for broiler production. Three trials were conducted in 10 environmental chambers; five chambers were stocked with males, and five were stocked with females. The chambers were initially set at 28, 29, 30, 31, and 32 C followed by daily reductions of 0.3 C for each beginning temperature. The dewpoint was set at 15.7 C throughout the experiments. Lighting was continuous, and feed and water were provided ad libitum. Weight gain and feed conversion were determined at 7, 14, and 21 d, and mortality was recorded as it occurred. Temperature did not affect weight gain or feed conversion for any period, but males were superior to females for these parameters for the 7- to 14-d and 14- to 21-d periods. Temperature affected mortality; most of the deaths occurred during the 0- to 7-d period and at the lowest temperature treatment. These results suggest that mortality is the best indicator of the effect of rearing temperature on performance.