Title: Nutrient management and environmental and societal issues affecting sustainability of feedlot finishing systems Authors
Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2013
Publication Date: July 30, 2013
Citation: Cole, N.A., Todd, R.W., Waldrip, H., Hales Paxton, K.E., Macdonald, J.C. 2013. Nutrient management and environmental and societal issues affecting sustainability of feedlot finishing systems. American Society of Animal Science meeting, Indianapolis, Indiana, July 9-13, 2013. Journal of Animal Science, 91:E-Supplement 2. Technical Abstract: Cattle evolved on a diet consisting primarily of forages. Thus, it is often assumed that the "ideal" system for producing cattle is pasture-based. In contrast to much of the world, beef cattle in North American typically spend a portion of their life in feedlots where they are fed diets high in grains and/or by-products. Feeding cattle nutritionally balanced, high-energy diets in confinement has many advantages over pastoral systems. However, feeding cattle in confinement leads to a concentration of nutrients into a small geographic area. Significant environmental and economic concerns include accumulation of nutrients, extraneous losses of nutrients to ground, and surface water, removal of accumulated manure, excretion of pathogens, and physiologically active compounds (PAC), and emissions of ammonia, greenhouse gases (GHG), odors, and dust. The public often views with concern, animal welfare, and the use of growth promoters and antibiotics. Nutrition and management practices influence the quantity of nutrients excreted by the animal, transformations, and movements of those nutrients, as well as losses of ammonia, volatile organic compounds, particulate matter, GHG, and PAC. Fortunately, ruminants can readily utilize a variety of high-fiber by-products to produce high-quality protein. The growth of the grain-based bio-fuel, and corn sweetener industries has provided cattle feeders with a large supply of by-products (distiller's grains, corn gluten feed, etc.) that can be substituted for feed grains. Because these byproducts are usually high in fiber, N, P, and S, when fed at high dietary concentrations, manure production, N, P, and S excretion, enteric methane emissions, and ammonia, nitrous oxide, and hydrogen sulfide emissions from manure are all increased. However, feeding lower concentrations (< 30% of DM) of these by-products, and use of grain processing techniques such as steam flaking may actually decrease the environmental footprint of feedlots by decreasing the quantity of feed grains required.