Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 26, 2004
Publication Date: August 15, 2004
Citation: Miles, D.M., Owens, P.R., Rowe, D.E., Branton, S.L. 2004. Spatial disparity of ammonia flux within a broiler house at one and 21 days of age [abstract]. Poultry Science. 83(supplement 1):146.
Ammonia concentrations greater than 25 ppm in broiler houses have been linked to emasculated birds. The objectives of this study were to measure ammonia and other gas fluxes in a commercial broiler house and assess any spatial variabilities. Application of these findings include the development of optimum sampling methods as well as the identification of characteristics of modern tunnel ventilated houses that contribute to gas emissions. Researchers hypothesize that litter age, moisture, pH, temperature, and airflow patterns affect gas flux values and these parameters vary spatially. Ammonia, nitrous oxide, carbon dioxide, methane, and carbon monoxide were measured using a photoacoustic multigas analyzer along with flux boxes. Samples (n=36) were collected systematically throughout the house along a set grid. Twenty-eight flocks had been grown on the litter prior to the summer flock sampling with chicks in the house at one (placement) and 21 (mid-growout) days of age. At one day of age during half-house brooding, average NH3 flux was 498 mg/m2-hr for the brood area and 372 mg/m2-hr for the vacant end of the house with peak areas near the middle of the cool cell end (where airflow is not well established) and near the north side wall (an area of high litter moisture, 37%). At 21 days of age, litter temperatures were reversed from those at chick placement and were greater near the fan end of the house. Both ranged from about 25.6 to 31.9 C. Litter pH was greater in the nonbrood half of the house at placement and mid-growout. Average NH3 flux for the mid-growout was 136 and 310 mg/m2-hr for the brood and fan ends. A peak area for NH3 flux in mid-growout was evident approximately 7 m past the midpoint of the house (towards the fans) and correlated to high pH (~8), high litter moisture (~33%), and high CO2 flux (12500 mg/m2-hr). The spatial variability of these parameters demonstrates that increased NH3 flux relates to high litter moisture as well as greater litter temperatures and CO2 flux and NH3 flux decreases on average from placement to mid-growout.