|Dozier iii, William|
Submitted to: Journal of Applied Poultry Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/15/2006
Publication Date: 9/15/2006
Citation: Dozier III, W.A., Price, C.J., Kidd, M.T., Corzo, A., Anderson, J., Branton, S.L. Growth performance, meat yield, and economic responses of ross x ross 308 broilers provided diets varying in metabolizable energy from 3o to 59 days of age during low and moderate temperatures. Journal of Applied Poultry Research. 15:383-393. Interpretive Summary: Feed cost represents 65% of the total live production cost for broiler chickens that supports an industry that produces 8 billion birds annually. Approximately 13% of the total number of broilers marketed is greater than 7.5 lb. Broilers raised to these heavy weights consume about 17.0 lb per bird and these heavy birds are less efficient of converting nutrients into meat compared with smaller broilers. Dietary cost can be greatly influenced by energy contributing ingredients. Information is sparse on dietary energy needs of broilers grown to heavy weights. Results indicated that dietary energy needs were higher with broilers produced during a summer than winter environment to optimize feed conversion. Broiler companies may need to increase dietary energy from 3,220 to 3,260 kcal/kg during summer production with broilers from 30 to 60 days of age.
Technical Abstract: Two studies examined responses of broilers to diets varying in AME from 30 to 59 d of age. A 59 d termination allows for evaluation of energy needs to applicable to “big bird” programs, as research on nutritional needs for such programs is warranted. Two experiments were conducted; experiment (exp.) 1 having low temperatures while moderate temperatures were used in exp. 2. The treatments in exp. 1 and 2 were AME concentrations ranging from 3,175 to 3,310 with CP, TSAA, and Lys being identical across all treatments. In exp. 2, an additional treatment consisted of a diet containing 3,310 kcal AME/kg with CP, TSAA, and Lys being increased to 104% of those specifications used in the other treatments so as to minimize differences in energy:CP ratio. In both experiments, feed consumption and conversion decreased linearly as dietary AME increased, but breast meat yield was reduced with the high AME diet and only increasing amino acids in exp. 2 ameliorated the negative effect. Live production costs and gross feeding margin (bird return over feed costs) were optimized in exp. 1 with 3,220 kcal AME/kg of diet, but 3,310 AME kcal/kg of diet and increased amino acids were needed for improved monetary returns in exp. 2. In both experiments, broilers had similar caloric consumption indicating that these broilers can compensate to varying dietary AME concentrations within practical limits. These results demonstrated that the response to dietary AME was more pronounced under moderate ambient temperatures.