Distillers grain is an important co-product of drymill ethanol production. Drymill ethanol production process uses only the starch portion of the corn, which is about 70% of the kernel. All the remaining nutrients - protein, fat, minerals, and vitamins - are concentrated into distillers grain, a valuable feed for livestock. A bushel of corn weighs 56 pounds and will produce at least 2.8 gallons of ethanol and 17 pounds of distillers grain.
Distillers grain can be fed to livestock wet or dry. Dried distillers grain (DDG) is the most common variety. Drying the distillers grain increases its shelf life and improves its ability to be transported over longer distances. If a consistent nearby market can be secured, ethanol producers can supply the feed as wet distillers grain (WDG). The wet form is not as easily transportable, but the cost of drying the product is removed.
Dried distillers grain with solubles (DDGS) is the form available to the feed industry. The liquid that is separated from the mash during the distilling process is partially dehydrated into a syrup, then added back onto the dried distillers grain to create DDGS.
DDGS is a high quality feedstuff ration for dairy cattle, beef cattle, swine, poultry, and aquaculture. The feed is an economical partial replacement for corn, soybean meal, and dicalcium phosphate in livestock and poultry feeds. Historically, over 85% of DDGS has been fed to dairy and beef cattle, and DDGS continues to be an excellent, economical feed ingredient for use in ruminant diets.
Source: http://www.ethanol.org/index.php?id=38&parentid=8
See Also:
The Ethanol Report:2007 vs. 2008