by James I. Sprague, Ph. D. , Livestock Nutritionist

A valuable co-product from ethanol production
With the advent of ethanol production used to blend with gasoline, two by-products are left over for cattle feeding. The products are distillers grains and condensed distillers solubles. Originally, the products were either fed locally or dried and then sold to cattle producers or feed manufactures. But because of the expense in drying, they are now being offered in the wet form to cattle feeders.

Dried distillers grain is a valuable feed ingredient, however the wet form works very well for growing and finishing cattle. It is very palatable, and the moisture adds conditioning to dry cattle.

Practical experience with distillers grain
Since the development of a plant at Russell, Kansas, wet distillers grains are used by feedlots in Kansas. One of their customers is Rex Stanley Feedyard at Dodge City. The product is delivered by special trucks that place the product on the concrete bunker area.

John Thornton, consulting nutritionist for the Stanley’s, reports the product on a dry basis at his clients’ yards is 31.8 percent protein, 16 percent acid detergent fiber (ADF) and 9.4 percent crude fat (mostly the oil from the milo), 0.77 percent phosphorus, and about 60 percent moisture. These analyses make this product a very good source for protein and phosphorus supplementation. Probably only a small amount of urea and calcium carbonate are needed in the supplement along with additives, vitamins, and trace minerals.
We also know that part of the protein is rumen degradable, and some is escape protein from the rumen. This means, in my opinion, a small amount of urea should be fed along with the distillers grain to feed the rumen microbes. A nutritionist can help formulate cattle rations with distillers grain.

Production of wet distillers grain
In Kansas, the majority of the wet distillers grains are manufactured from sorghum grains (milo) because of the cost of the grain. Since the original grains are concentrated by a factor of three, the protein is appromately 30 percent crude protein on a dry basis. In alcohol production, the grain is ground, water added with an enzyme and time allowed for the enzyme to change some of the starch to maltose sugar. The yeast is added and allowed to ferment and then the alcohol is distilled from the mixture. The residue is pressed or centrifuged of moisture and solubles. The remainder is wet distillers grain. The soluble products can be condensed, and that is called condensed distillers solubles. They may be combined as wet distillers grains with solubles.

The fermentation process improves the digestibility of the protein compared to dry rolled or flaked milo. Nutritionists and cattle feeders know the starch and protein of milo grain is difficult for cattle to digest, as noted by the grain in the manure. The reason is, in simple terms, the protein forms a tight wrap around the starch granules in sorghum grain. But because of the enzyme action and the fermentation, the protein of the residue is more digestible than in the original grain.

Research
Research at Iowa State University has demonstrated the nutritional value of both wet distillers grain and condensed distillers soluble. Their latest research with condensed distillers grains indicates it can “replace a portion of the corn and supplemental nitrogen in finishing rations.” Cattle feeders will use the products primarily as a protein source for growing and finishing rations. ©