Methane and ammonia emissions from a beef feedlot in western Canada for a twelve-day period in the fall

Commercial feedlot operations are becoming a mainstay in the Canadian beef industry. These large operations that typically raise thousands of animals at a time represent a large localized source of methane (CH 4 ) and of atmospheric pollutants such as ammonia (NH 3 ) and particulate matter. An inverse dispersion model was utilized to calculate CH 4 and NH 3 emissions from a commercial cattle feedlot and an adjacent runoff retention pond. The feedlot measurements were collected within the interior of the feedlot enabling a near continuous emissions record over the 12 d of the study period. Average daily emission estimates of CH 4 and NH 3 were 323 and 318 g animal -1 d -1 , respectively. The CH 4 emissions represent 4% of the gross energy intake (GEI) and NH 3 emissions represent 72% of the total N intake. Emissions from the runoff retention pond associated directly with the feedlot operation were approximately 2.7 and 2% of the daily average feedlot emissions of CH 4 and NH 3 , respectively.