Feeding Ethanol Byproducts to Dairy and Beef Cattle1

Distillers grains with solubles (DGS) and corn gluten feed (CGF) are the major byproducts of ethanol production fed to cattle. Both DGS and CGF can be fed wet or dried with animal performance usually similar when fed as wet or dried products; however, some research results favored the wet products. Cattle diets can contain DGS or CGF as replacements for portions of both concentrates and forages. Distillers grains is a very good protein (>30% CP) source which is high in ruminally undegradable protein, and is very good energy (NEL ~2.25 Mcal/kg of DM) source for lactating cows, growing, and finishing cattle. The modest fat concentration (10% of DM) and the readily digestible fiber (39% NDF) contribute to the high energy in DGS. Distillers solubles are often blended with distillers grains to provide DGS, but the solubles can also be fed separately as "thin stillage" or as "condensed corn distillers solubles". Protein and energy values are similar for distillers grains with or without solubles but the phosphorus content is elevated when solubles are included. The recommended amount of DGS for feeding lactating dairy cows is up to 20% of total ration dry matter; higher amounts as much as 40 to 50% of ration dry matter can be successfully fed as an energy source to finishing cattle. Corn gluten feed is a medium protein (24% CP) and medium energy (~1.73 Mcal NEL/kg of DM) feed that also contains an abundance of digestible fiber (35% NDF). While CGF can be fed at higher amounts than one usually feeds DGS, optimal production and feed efficiency of lactating cows occurred with 18 to 27% of ration DM as CGF. Larger amounts, replacing nearly all of the concentrates and forages, were successfully fed to finishing cattle. The fiber in DGS and CGF, which often replaces high starch feeds, does not eliminate acidosis but minimizes its problems. Corn coproducts such as corn gluten meal (65% CP) and other modified products from dry and wet milling plants are additional items available as cattle feeds. Innovations in processing technology will likely result in additional products for future use as livestock feeds.