Assessment of greenhouse gas emissions from poultry enteric fermentation

Emissions of nitrous oxide (N2O) and methane (CH4) from poultry enteric fermentation were investigated using a respiration chamber. Birds were placed in a respiration chamber for certain intervals during their growing period or for the whole life cycle. The accumulated gas inside the chamber was sampled and analyzed for N2O and CH4 production. A curve for gas production during a life cycle was fitted. The calculated area under the curve estimated the emission factor of poultry enteric fermentation on a life cycle basis (mg bird(-1) life cycle(-1)). This method can be used to estimate CH4 or N2O emissions from different types of avian species taking into account factors such as diet, season or thermal effects. The CH4/N2O emission factors estimated for commercial broiler chickens, Taiwan country chickens and White Roman Geese were 15.87/0.03, 84.8/16.4 and 1,500/49 (mg bird(-1) life cycle(-1)), respectively, while the calculated CH4/N2O emission from enteric fermentations were 3.03/0.006, 14.73/2.84 and 9.5/0.31 (Mg year(-1)), respectively in Taiwan in the year of 2000. The described method is applicable to most poultry species and the reported emission factors were applicable to meat type poultry only.