The Effects of Environmental Temperature, Sex, and Dietary Energy Levels on Growth Performance of Large White Turkeys

Six hundred forty Large White turkeys in each of two experiments were sexed and subjected to constant environmental temperatures of 10.0, 18.3, 26.7 and 35.0 C, and a high or low energy diet in a factorial arrangement of treatments from 8 to 24 weeks. Maximum body weight gains were obtained when birds were maintained at 10.0 and 18.3 C, while at 26.7 C and 35.0 C, weight gains were reduced 6 and 13%, respectively, from that observed in birds reared in the 10.0 C environment. Body weight gains were greater in males at 18.3 C and at 10.0 C for females. Trends in feed efficiency were the same in both sexes. Feed efficiency improved approximately 1.2% for each 1.0 C increase in temperature up to 26.7 C. The addition of 8% fat to the diet while holding the energy to protein ratio constant had no effect on weight gains, but it did significantly improve the feed efficiency by 4.9%. In general, environmental temperature, sex and diet had no significant effect on feathering, live market quality or New York dressed weight. Temperature altered eviscerated yields, with the highest yields being obtained at 18.3 and the lowest at 35.0 C. Temperature environment had no apparent effect on the levels of CO2 or NH3 in the pens. The incidence of pendulous crops increased at the higher temperatures. Results of this study indicate that turkeys can be reared efficiently in environmental temperatures between 10.0 and 26.7 C when diets contain up to 8% stabilized fat.