2011 Annual Report 1a.Objectives (from AD-416) The objective of this research is to develop nutritional, thermal, and lighting strategies to improve production efficiency of broilers grown to heavy market weights. The four individual objectives are: characterize production efficiency and meat yield of heavy broiler chickens fed low energy diets; develop precision feeding strategies with an emphasis on DDG/S for heavy broiler chickens to optimize nutrient and energy utilization for production efficiency; determine the effects of apparent environmental temperature on production efficiency and physiological responses of heavy broiler chickens; and evaluate production efficiency and physiological responses of heavy broiler chickens as a function of light intensity. 1b.Approach (from AD-416) This project utilizes a systems approach to address current knowledge gaps associated with nutritional, temperature, and lighting needs of broilers grown to heavy weights. Four research areas are planned to address these concerns. First, baseline knowledge of feeding heavy broilers low energy diets using corn soybean meal based diets will be assessed. This will be followed by evaluation of the inclusion of co products from ethanol and biofuel production in diets formulated to low energy; second, a diet formulation model will be developed to minimize poor broiler performance associated with nutrient variability when co products from ethanol production are included in the diet; third, factors influencing the thermal environment of heavy broiler chickens will be evaluated; fourth, production efficiency of broiler chickens subjected to low light intensity grown to heavy weights will be assessed. This research will provide the broiler industry with scientific information to make dietary and management decisions needed to improve production efficiency of broilers grown to heavy weights. 3.Progress Report This research addresses Project Plan Objective 1: “Characterize production efficiency and meat yield of heavy broiler chickens fed low energy diets”. Broilers were fed experimental diets differing in apparent metabolizable energy (AME) concentration and energy source from 35-47 day and 47-60 day. While analysis of the data is incomplete, growth and meat yield data will indicate the interaction of AME concentration and energy source in practical broiler diets which will allow producers to formulate diets on a least-cost basis without limiting growth potential and meat yields. In addition, this research addresses Project Plan Objective 3: “Determine the effects of apparent environmental temperature on production efficiency and physiological responses of heavy broiler chickens.” A series of experiments was conducted to determine live production responses and processing characteristics of broilers aged 63 days subjected to temperature and humidity combinations ranging from 60 to 80°F and 50 to 80%RH from 42 to 63 days of age. Significant declines in live performance (reduced body weight gain and increased feed conversion) were observed at 80°F, which is traditionally considered thermoneutral in regards to productivity and production efficiency. Results showed that the temperature-humidity index for still air conditions can be used as a predictor of live performance and thus can be incorporated into management recommendations and building controls to improve production efficiency and profitability for contract growers to predictive control of ventilation and cooling systems. Finally, this research addresses Project Plan Objective 4: “Evaluate production efficiency and physiological responses of heavy broiler chickens as a function of light intensity”. Results demonstrated that exposure of modern broilers to varying levels of light intensities ranging from 0.2 to 25 lux had no major effects on production performance, blood physiological variables, and welfare indices evaluated. These data are important for establishing welfare guidelines and profits to modern commercial poultry facilities by using low lighting environment to reduce hyperactivity, pecking damage, and reduce energy costs while improving overall poultry welfare and environment. Review Publications Dozier, W.A., Corzo, A., Kidd, M.T., Tillman, P.B., Branton, S.L. 2011. Determination of the fourth and fifth limiting amino acids of broilers fed diets containing maize, soybean meal, and poultry by-product meal from 28 to 42 days of age. British Poultry Science. 52(2):238-244. Dozier, W.A., Corzo, A., Olanrewaju, H.A. 2011. Apparent metabolizable energy needs of male and female broilers from thirty-six to forty-seven days of age. Poultry Science. 90:804-814.