Review of new information on the use of wet and dry milling feed by-products in feedlot diets

The processing of grains to produce human foods, beverages, or fuel ethanol has resulted in a wide variety of associated feed by-products. Hominy feed and distillers by-products are feed by-products associated with two distinctly different dry-milling industries. Hominy feed contains approximately 57% starch, 11% CP, and 5% fat (DM basis). When fed to finishing cattle, hominy feed has approximately 87% the net energy value of corn. Distillers by-products contain 25 to 32% CP and 13 to 16% fat (DM basis). Wet distillers by-products have approximately 97 to 147% the net energy value of corn. The energy value of wet distillers by-products may be affected by the type of grain used in the fermentation process (corn vs grain sorghum) and the amount of solubles added to the distillers grains. Drying distillers by-products reduces their net energy value but does not seem to affect their protein value. Corn gluten feed (CGF) and corn gluten meal (CGM) are feed by-products of the wet milling industry. Corn gluten feed is composed primarily of bran and steep. Corn gluten feed is lower in both CP (14 to 24%, DM basis) and escape protein (20 to 30%, % of CP) than CGM, but it is high in net energy for gain (90 to 114% of corn; DM basis). As the proportion of steep increases and bran decreases in CGF, the CP and net energy for gain content increases. When fed to finishing cattle, dried CGF has a lower net energy value than wet CGF. Wet distillers by-products and wet CGF seem to reduce the incidence of subacute acidosis. Because feed by-products have a high nutritional content and are often economically priced, they are excellent sources of energy and protein for feedlot cattle.