In addition to producing fuel, the ethanol industry also helps to feed the world. Many feed products can result from the various ethanol production processes. In fact, more grain is available for feed and food use today than at any other time in history. This section will answer many of the frequently asked questions (FAQ) on distiller’s grains.
What are the differences among DDGS, corn gluten feed and corn gluten meal?
DDGS is a co-product of the dry milling manufacturing obtained after the removal of ethyl alcohol by distillation from yeast fermentation of a grain or a grain mixture by condensing and drying at least three-fourths of the solids of the resultant whole stillage by methods employed in the grain distilling industry. DDGS is produced by blending corn distillers liquid solubles on the wet corn distillers grains before being dried. If not dried, it is sold as wet distillers grains (WDG). DDGS can also be produced from other grains, such as barley, rye, sorghum and wheat.
Corn gluten feed is a co-product of wet milling manufacturing. It is defined as that part of the commercial shelled corn that remains after the extraction of the larger portion of the starch, gluten and germ by the processing employed in wet milling manufacture of corn starch or syrup. Corn gluten feed is significantly lower in energy, protein and fat, than DDGS and therefore is valued lower than DDGS in many diets.
Corn gluten meal is a co-product of wet milling manufacturing. It is defined as the dried residue from corn after the removal of the larger part of the starch and germ, and the separations of the bran by the process employed in the wet milling manufacture of corn starch or syrup, or by enzymatic treatment of the endosperm.
Corn gluten meal is used as a protein source in poultry and livestock feeds. It also serves as a good source of xanthophylls (golden yellow).
The table below is a comparison of the major nutrient analysis from NRC for swine.
|DDGS||Corn Gluten Feed||Corn Gluten Meal|
|Metabolizable Energy, Kcal/Kg||2820||2605||3830|
What is the nutrient analysis of DDGS?
A rule of thumb for the nutrient analysis of DDGS is that it is approximately three times the nutrient analysis of corn. For nutrient profiles for Iowa and other states’ ethanol plants in production, visit the University of Minnesota web site.
Additional nutrient analysis is available upon request. The following table shows the results from a sampling of 10 plants for one year (total of 118 samples).
|Nutrient||88% Dry Matter|
|Metabolizable Energy (Kcal/lb.)||1500|
* Apparent Ileal Digestibility
What are the major ingredients that affect the cost of DDGS?
The value of DDGS nutrient contribution to the final diet is basically determined by the cost of corn, soybean meal, and dicalcium or monocalcium phosphate for which DDGS is substituted when added to the diet.
How consistent are the various product characteristics of DDGS?
The particle size, color, bulk density and nutrient analysis can vary slightly from plant to plant. The recommended purchasing practice to optimize the consistency of DDGS is to purchase DDGS from one plant or selected plants. The factors that can be involved include: The equipment used for drying and temperature used during drying. The drum dryers produce a more granular product whereas the flash dryer produces a finer particle DDGS. The resultant DDGS particle size produced will affect bulk density. Source of corn and final ratio of wet corn distillers grains to corn distillers liquid solubles going into the dryer can affect nutrient analysis. Typical bulk density is 35 to 36 lbs/cubic foot.
The typical color of DDGS is generally in the range of “golden.” If the color is “dark brown or darker,” it would be an indication that the drying process overheated the DDGS and would reduce the digestibility of the amino acids.
Swine, poultry, dairy and beef researchers from several land grant colleges have conducted several experiments to evaluate the use of DDGS in feeding programs. Many of these experiments have been summarized and reported at various animal and poultry science meetings. The results of these experiments are reported on the University of Minnesota’s DDGS website.
Does GMO corn affect the quality of DDGS?
Currently, ethanol plants do not differentiate between GMO and non-GMO corn. Research that has been done with GMO corn suggests that it would not affect the quality of resultant DDGS.
Can DDGS be pelleted?
Yes. However, obtaining a high-quality pellet may require a different die than the dies typically used to pellet corn-soybean meal diets.
Where can I purchase distillers grains in Iowa?
For a list of marketers who sell distillers grains in Iowa, please click here. Use in Animal Diets.
What livestock species provides the greatest value for DDGS?
Ruminants, especially dairy, provide the greatest value because of the nutrient contribution and the bypass protein of DDGS.
What are the major nutrient guidelines for the use of DDGS in nonruminant diets?
Use the available phosphorus value because the bioavailability of phosphorus is 85% in DDGS, which is higher than the bioavailability of phosphorus in corn of 14%, 31% – 44% in soybeans, or 23% – 47% in soybean meal. Use digestible amino acid values to more accurately balance the amino acid requirements of the animal when incorporating DDGS into the diets.
What levels of DDGS are being used in nonruminant diet formulations?
A common level is 10% in many nonruminant diets. However, research has shown that DDGS has been successfully incorporated into swine diets up to 20%, and has resulted in similar performance and carcass characteristics as pigs fed a typical corn-soybean meal diet.
Do DDGS provide any added values when used in swine diets?
Research to determine these added values is ongoing. Many field reports indicate improved “gut health” of growing-finishing pigs.
Can phytase be added to diets that contain DDGS?
Yes, research has demonstrated that phytase added to typical corn-soybean meal diets (at 225 FTU/lb. of complete feed) replaces approximately 10 to 11 lb/ton of inorganic phosphorus and reduces phosphorus excretion in the manure by approximately 30%. The addition of 10% DDGS to the diet replaces approximately 6 to 7 lb/ton of inorganic phosphorus.
Are there special precautions for handling and storing wet or dry distillers grains with solubles?
Generally, DDGS will contain approximately 12% moisture or less. Therefore, when properly stored the quality of DDGS will be maintained, as well as any other protein or grain ingredients used in diet formulations.
Flowability agents may be used to enhance flowability of DDGS, especially if the DDGS is of the finer particle size or contains excessive moisture.
Properly processed and stored DDGS does not require the use of antioxidants or mold inhibitors.
Wet corn distillers grains with solubles,which contains approximately 65% to 70% moisture, is the product available before being dried. Modified wet DDGS, which contains approximately 50% moisture, is also available from some plants. Additives are available from commercial suppliers to enhance the storage life of the wet corn distillers grain with solubles. Practical experience suggests that an open storage time of approximately a week, depending on environmental temperature, can be maintained without product deterioration.
What is the risk of mycotoxins in DDGS?
Myotoxins can be present in DDGS if the grain delivered to an ethanol plant is contaminated. Myotoxins are not destroyed during the ethanol production process or the drying process to produce distillers grains. However, the risk of myotoxin contamination in U.S. distillers grains is very low because it is uncommon for most of the major growing regions in the U.S. to have climatic and weather conditions that lead to myotoxin production from corn. Furthermore, the vast majority of ethanol production facilities monitor grain quality, similar to practices implemented at grain elevators, and reject sources that are contaminated with myotoxins.
What level of distillers grains are being recommended in diet formulations?
Research indicates distillers grains can account for the percent of daily feed rations as follows:
- Beef cattle: 10-40%
- Dairy cows: 10-30%
- Swine: depends on growth stage
- Poultry: 10-15%
Why are ethanol producers extracting oil from DDGS?
The current market price and demand for crude corn oil is very attractive as another revenue source for ethanol production facilities and the availability and relatively low cost of adding oil extraction equipment to existing ethanol plants makes this process very profitable.