DES MOINES, Iowa, August 1, 2007 - The rapid expansion of the ethanol industry has greatly increased the volume of distiller's grains available for livestock feed. Nutritionists with Pioneer Hi-Bred suggest feeding distiller's grains for high protein and fat values, but keeping a close eye on sulfur and phosphorous content in grain.
"The industry is reporting that 75 percent to 80 percent of the distiller co-products are fed to dairy and beef cattle," says Steve Soderlund, Pioneer beef nutrition manager. "When evaluating the potential value of these products, make sure you request a nutrient profile from the plant. Consider how these products complement your existing feeding program."
Soderlund adds that one of the biggest factors in determining the nutrient content of the distiller co-products is the grain source used by the ethanol plant.
"In comparison to corn, if the plant is using sorghum as a primary grain source, expect to see higher protein levels, but a lower fat level," says Soderlund.
Feeding distiller's grains
University beef cattle feeding trials have found the energy values of distiller's grain can be as much as 9 percent better than corn. Soderlund says this is due primarily to the fat content in the product which is 2.25 to 2.5 times the caloric density of starch. Most distiller's grains contain between 10 percent to 12 percent fat and 24 percent to 30 percent protein.
"Including distiller's grains at 15 percent to 20 percent of the dry matter in a beef finishing ration generally will meet the protein requirements and contribute to the energy needs of the cattle," says Soderlund. "In forage-based diets for beef cows, distiller's grains can be used as a source of supplemental protein and energy. The amount fed depends on the desired performance and nutrient content of the forage."
Be aware of two potential mineral concerns, sulfur and phosphorus, when feeding distiller's grains to feedlot cattle. Keep sulfur content to less than 0.4 percent of the dry matter intake from all sources, including water. Polioencephlemalacia - a disease affecting the central nervous system of cattle - can result from elevated sulfur levels. In addition, phosphorous levels should be monitored. The phosphorous content typically will be three times higher in distiller grains than in corn grain.
"Unless very high levels of calcium are supplemented, an unfavorable calcium-to-phosphorous ratio may develop," says Soderlund. "Urinary calculi - water belly - can develop in feedlot steers under these conditions. Keep the calcium-to-phosphorous ratio between 1-1 to 1.5-1."
Distiller's grains will be used primarily as a protein and fat source in dairy rations, which generally limits its inclusion rate to less than 10 percent of the diet. However, university tests have shown that distiller grains can be fed at up to 20 percent of the ration when feeding higher forage levels.
"Dairy producers need to pay close attention to the amount of effective fiber in the diet," notes Soderlund. "Even though distiller grains contain a relatively high level of neutral detergent fiber, the fiber is very fine and will not maintain good rumination."
Traditional ethanol co-products
There are several different distiller feed products produced by the ethanol industry. The highest-volume product is distiller's grains, which primarily contains unfermented grain residues - protein, fiber and fat. The remaining fraction is called thin stillage which contains yeast cells, soluble nutrients and very small corn particles.
"Most large distilleries have the capability to dry their distiller's grains - DDG," says Soderlund. "The thin stillage is concentrated to a molasses-like consistency to form condensed distiller's solubles (CDS). The CDS product can be sold directly to liquid feed manufacturers or dried and placed back on the DDG to produce distiller's grains plus soluble (DDGS)."
While the majority of distiller's grain produced in the upper Midwest is sold as DDGS, a high percentage produced in the High Plains is fed as wet distiller's grain (WDG) locally - reducing energy costs associated with drying. WDG needs to be fed within four to five days before warm weather causes significant spoilage.
Pioneer is developing genetics that not only yield higher ethanol but also produce co-products with higher nutritional value. Strategies to improve the amino acid profile, lower fiber content, lower phosphorus content and improve fatty acid profiles are all being explored.
Pioneer Hi-Bred, a DuPont business, is the world's leading source of customized solutions for farmers, livestock producers and grain and oilseed processors. With headquarters in Des Moines, Iowa, Pioneer provides access to advanced plant genetics in nearly 70 countries. DuPont is a science-based products and services company. Founded in 1802, DuPont puts science to work by creating sustainable solutions essential to a better, safer, healthier life for people everywhere. Operating in more than 70 countries, DuPont offers a wide range of innovative products and services for markets including agriculture and food; building and construction; communications; and transportation.