Commercial-scale Studies of the Effect of Broiler-protein Intake on Aerial Pollutant Emissions

Research is being conducted to develop integrated management systems for the rearing of broilers. The focus is on real-time dietary control to achieve growth-performance targets according to the prescribed criteria that include pollution emission considerations. Two ‘sister’ projects are in operation: one studying growth-performance and the other monitoring aerial pollution emission responses to dietary control. Both research projects utilize the same commercial-scale feeding trials on flocks of approximately 34 000 birds. Results are presented from the pollutant-monitoring project for one of a base set of experiments where a different protein level diet was supplied to each of four houses. Male broilers received ad libitum diets with target protein levels (based on lysine content) of 85, 90, 100 or 110% of the normal commercial level. The experimental arrangement is described, and results are presented of the emissions of ammonia, dust and odour monitored from the four houses throughout the 6-week rearing period. Observable correspondences were found between the ammonia emissions from and the actual total protein consumed within each house. Ammonia concentrations were consistently below 15 p.p.m., and dust and odour concentrations were reasonably consistent with previously reported levels. In the longer term, the pollution-monitoring and the bird-performance-monitoring projects aim to enable real-time control of diets to be formulated with regard to both profitability and pollution emissions.