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Effect of changes in management practices and animal performance on ammonia emissions from Canadian beef production in 1981 as compared with 2011

Legesse, Getahun, Kroebel, Roland, Alemu, Aklilu W., Ominski, Kim H., McGeough, Emma J., Beauchemin, Karen A., Chai, Lilong, Bittman, Shabtai, McAllister, Tim A.
Canadian journal of animal science 2018 v.98 no.4 pp. 833-844
ammonia, ammonium nitrogen, average daily gain, beef, beef cattle, beef production, bioenergy industry, breeding, byproducts, carcass weight, corn, diet, emissions, feedlots, grazing, herd productivity, management systems, manure handling, reproductive efficiency, total nitrogen
The present study compared ammonia (NH₃) emissions from Canadian beef production in 1981–2011. Temporal and regional differences in cattle categories, feed types and management systems, average daily gains, carcass weights, and manure handling practices were considered. A scenario-based sensitivity analysis in 2011 estimated the impact of substituting corn dried distillers’ grains with solubles (DDGS) for grain in feedlot diets. On average, 22% of the total nitrogen (N) intake was lost as ammoniacal nitrogen (NH₃-N) in both years. Manure emission sources were consistent across years, averaging 12%, 40%, 28%, and 21% for grazing, confinement, storage, and land spreading, respectively. Emissions per animal in 1981 and 2011 were 16.0 and 18.4 kg NH₃ animal⁻¹ yr⁻¹, respectively. On an intensity basis, kilogram of NH₃ emitted per kilogram of beef decreased 20%, from 0.17 in 1981 to 0.14 in 2011. This reduction was attributed to increases in reproductive efficiency, average daily gain and carcass weight, and improved breeding herd productivity. In 2011, substituting DDGS for grain in feedlot diets increased total NH₃ emissions and losses per animal. Although addition of by-products from the bioethanol industry can lower diet costs, it will be at the expense of an increase in NH₃ emissions.