Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/16/2009
Publication Date: 3/16/2009
Citation: Kerr, B.J., Anderson, P.V., Shurson, G.C. 2009. Ethanol Corn Co-product Assessment Opportunities and Challenges in the Swine Industry. Journal of Animal Science. 87:82.
Technical Abstract: Corn milling for ethanol production has resulted in an increased variety of co-products for use in feed formulation, ranging from a highly digestible feedstuff such as dehulled, degermed corn (8.3% CP, 88% ST, 2.6% TDF, 0.2% EE), to high protein distillers dried grains (44% CP, 7.3% ST, 31% TDF, 2.9% EE), to fibrous corn bran (11% CP, 23% starch, 54% TDF, 5.1% EE). Likewise, distillers dried grains with solubles (DDGS) may have various amounts of oil removed such that the reduced oil DDGS may contain only 3% EE vs. the 11% found in typical DDGS. Empirical methods for determination of energy values are difficult, expensive, and variable. However, estimation of energy values from regression equations based on nutrient composition varies greatly depending upon which regression equation is used. Likewise, nutrient composition both within and between these co-products varies constantly and substantially depending upon the milling methodology. Results from a recent collaborative effort focusing on in vivo determination of ME content of corn co-products showed that ME ranges from 2,334 to 8,777 kcal/kg. Application of published regression equations to this data set to estimate ME from the analyzed chemical composition resulted in predicted ME values that did not match well with the empirically derived values, bringing into question our ability to accurately predict the energy value of corn co-products. Causes for these discrepancies are not fully understood, but likely include differences in methodology used to determine ME as well as variation in analytical composition of the feed ingredient itself. Lastly, the influence of exogenous enzymes and feed processing on co-product utilization needs to be better understood. In addition, the value of corn co-products as an available P source is poorly understood, and is influenced by processing method and dietary phytase supplementation. Lastly, the influence of processing method, solubles addition, and the interactive effects of fiber on availability of amino acids and other nutrients needs to be determined.