Informal Nutrition Symposium Biological limits to productivity

Abstract

SUMMARY There will obviously be biological limits to productivity in terms of growth rate of meat birds and egg production in layers and breeding stock. We continue to see an unprecedented increase in commercial performance, and to date, we have managed to accommodate this everincreasing potential as provided by the poultry geneticists. In many situations, we do not see the full genetic potential at the poultry farm because of myriad factors that negatively affect productivity compared with maintaining these birds under small-scale experimental conditions. Under such ideal conditions, we have realized 345 eggs in 365 d in some strains of white-egg layers, whereas handling individual broilers during trials has resulted in weights of almost 4 kg at 42 d. These values therefore represent the true genetic potential of these birds and suggest that we are nowhere near the biological limit to productivity in commercial flocks of layers, broilers, or turkeys. It is not the intent of this review to discuss the reasons for “reduced” commercial productivity; rather, the goal is to discuss potential factors that may influence the absolute biological limits to performance inherent today and, more important, in the future.