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 b roilers. The objective of this research was to determine the effect of five temperature regimens on the growth, feed conversion, and mortality of broi lers to 21 d of age; This information is needed to select the most profitab le conditions for broiler production. Three trials were conducted in 10 env ironmental chambers; five chambers were stocked with males, and five were s tocked 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 co ntinuous, 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 f or 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; mos t of the deaths occurred during the 0- to 7-d period and at the lowest temp erature treatment. These results suggest that mortality is the best indicat or of the effect of rearing temperature on performance.