Document Type


Publication Date



ethanol, cattle, livestock feed

Extension Number

ExEx 2036


Agricultural and Biosystems Engineering


The ethanol industry is currently in the midst of a considerable expansion period in South Dakota and surrounding states. As more ethanol plants are built and begin production, the availability of co-products for livestock feed will increase dramatically. Co-products may offer the cattle industry a tremendous opportunity to reduce feed costs without sacrificing performance. However, there are significant challenges that must be met before feeding these products. The majority of the new plants utilize a dry milling process to produce ethanol from corn. Dry milling (mash distillation) involves cleaning and grinding the grain into coarse flour. Then water and enzymes are added, which convert the starch into sugar. At this point the mixture, referred to as "mash," is cooked and sterilized. Once the mash has cooled, yeast is added to begin the fermentation process. Fermentation results in the production of ethanol, carbon dioxide, and residual grain particles called "spent mash." The entire mixture is then distilled to remove the ethanol and centrifuged to remove as much excess liquid as possible.


August 2002.