Distillers Dried Grains-Nutrient Digestibility
Researchers at South Dakota State University measured the digestible energy, nitrogen and phosphorus of ten distillers dried grains with solubles (DDGS) collected from ethanol plants in South Dakota and Minnesota. Eleven pigs were used in a 11x11 Latin square design experiment comparing the DDGS samples fed in a 1:1 ratio to corn. Results indicated a significant (P<0.001) difference between the ten DDGS samples in digestible energy (3,947-4,593 kcal/kg DM) and metabolizable energy (3,674-4,336 kcal/kg DM). The average digestible energy and metabolizable energy for DDGS and corn were 4,140 and 4,088 kcal/kg DM and 3,897 and 3,989 kcal/kg DM, respectively. When calculated on a percentage basis, nitrogen tension was similar for DDGS and corn. Whereas, apparent total tract digestibility of phosphorus for the ten DDGS samples averaged 59.1% compared to a value of 19.3% for corn. They concluded that that DDGS is variable; contains about the same energy as corn; and higher levels of organic phosphorus will be digested and absorbed.

Pedersen, C. M.G. Boersma and H.H. Stein. 2007. Digestibility of energy and phosphorus in ten samples of distillers dried grains with solubles fed to growing pigs. J. Animal Sci. 85: 1168-1176.

Five samples of distillers dried grains with solubles (DDGS) were collected and evaluated for energy and amino acid digestibilities using a precision-fed rooster assay. The Ohio State University study suggested that DDGS samples with darker color scores had lower amino acid and energy digestibilities. These results suggested that overheating during drying may cause Maillard reactions and lower total lysine, lysine digestibility and total metabolizable energy values. (Comment- Bottom line is the need to carefully characterize the DDGS source prior to diet formulation).

Fastinger, N.D., J.D. Latshaw and D.C. Mahan. 2006. Amino acid availability and true metabolizable energy content of corn distillers dried grain with solubles in adult cecectomized roosters. Poultry Sci. 85(7): 1212-1216.

Distillers Grains and Soybean Hulls
Researchers at the University of Florida conducted an experiment to evaluate the effects of dried distillers grains, soybean hulls, or a combination of the two ingredients in supplementing steers weighing 275kg consuming low quality hay. Results improved weight gains and nitrogen metabolism by supplementing the low-quality forage and a combination of 0.9 kg dried distillers grains and 2.05 kg soybean hulls optimized calf performance.

Wahrmund, J.L. and M.J. Hersom. 2007. Evaluation of dried distillers grains or soybean hulls to background beef calves. J. Animal Sci. 85: Suppl. 1: 410 (Abstract 526).

Another experiment was conducted to evaluate the role of distillers dried grains with solubles (DDGS) and soybean hulls in beef cattle finishing diets. The treatments consisted of diets containing various combinations of shelled corn, grass hay, soybean meal, DDGS and soybean hulls. The results of this study indicated that higher levels of DDGS (up to 40%) and soybean hulls (up to 44%) will result in similar quality and yield grades, but will require higher feed intake with lower average daily gains compared to diets containing shelled corn or limiting DDGS to less than 25 percent. They reported that cost of gain was not significantly different between treatments.

Walker, P.M., D. Admas and L.A. Forster. 2007. Evaluation of corn and soybean co-products in beef cattle finishing diets. J. Animal Sci. 85: Suppl. 1: 348 (Abstract T334).

Distillers Grains-Phosphorus Management
Fermenting the starch in corn to produce ethanol concentrates the phosphorus in distillers grains by about three-fold. Phosphorus levels in corn range from 0.27-0.33% compared to levels of 0.8-1.0% in distillers grains. A paper from Iowa State University reviewed a concern that feeding distillers dried grains with solubles may result in overfeeding phosphorus and the higher levels of phosphorus in the manure could cause environmental problems. The author pointed out that the potential problem would vary with the species and diet being fed. He concluded that the potential environmental problem could be minimized with an effective manure management plan.

Trenkle, Allen. 2006. With increasing availability of distillers grains will phosphorus be a problem for Iowa livestock producers? Iowa State University Animal Industry Report A.S. Leaflet R2124.