* Purdue Department of Agricultural and Biological Engineering
* Purdue Department of Animal Sciences
* Purdue BioEnergy page

September 25, 2008

Ag engineers: Production issues dragging down DDGS

WEST LAFAYETTE, Ind. - An ethanol byproduct suitable for livestock feed could be easier sold and used if it was more uniform each time it is produced, said two Purdue University agricultural engineers.

Dry distillers' grains with solubles (DDGS), the grain product left over after ethanol is produced from corn, is often chemically different from ethanol plant to ethanol plant and, sometimes, even within a plant, said Klein Ileleji and Richard Stroshine. Those differences can create shipping, storage and livestock feeding challenges, they said.

"The big issue with DDGS is the fact that the product is so variable," Ileleji said. "Obviously, that can have a huge impact on the final product and how it is handled."

"If livestock producers don't have a consistent feed product, it makes it difficult for them to cost effectively formulate a good feed that will provide their animals with the nutrition they need," Stroshine said.

Ileleji and Stroshine will address DDGS handling and storage issues during a session of the Integrated Corn Ethanol Co-product Conference. The conference takes place from 8:15 a.m. to 4:40 p.m. Nov. 18 at the Beck Agricultural Center. The center is located at the Purdue Agronomy Center for Research and Education, seven miles northwest of Purdue's West Lafayette campus along U.S. 52.

The conference is intended for those in the ethanol industry, livestock producers and animal nutritionists. Conference registration is free for those attending at the Beck Agricultural Center, although preregistration is required. The conference also can be viewed online. The Internet Webinar fee is $20 for members of the American Society of Animal Science and Purdue Extension county educators, and $30 for all others.

DDGS can take on different physical properties from batch to batch during the ethanol extraction and post-extraction processes, Stroshine said.

"In that process we break the corn down and let the starch ferment into ethanol," he said. "Whatever is left - the liquid remaining after ethanol is removed, along with the hulls, the germ, the protein and the gluten material - goes into the DDGS. These leftovers are separated into solid and liquid portions. The solids are sent to a rotary dryer, where different amounts of the liquid condensed solubles can be added back. Differences in the amounts of solubles added cause variations in composition and particle size."

Individual DDGS particles can be larger or smaller, meaning some particles might be holding more sugars, oil and moisture than others, Ileleji said. When that happens, and under favorable environmental conditions such as high humidity and temperatures, DDGS particles can stick together and form clumps, or what Ileleji calls caking. Problems occur when DDGS cake up in bulk shipments transported by rail car or other means.

"When the product cakes up it can be very difficult to unload," Ileleji said. "That makes DDGS expensive to move. Because the product can cake up, two major rail carriers have stopped transporting DDGS."

During their conference session Ileleji and Stroshine will present research they've conducted on identifying the causes of DDGS variability and suggestions on how the ethanol industry can produce a more uniform product. In a separate session, Ileleji will provide an overview of Purdue DDGS research.

Other Purdue speakers are scheduled to address livestock-related DDGS issues, including digestibility, animal performance and carcass qualities, feed supplements, effects on excretion and manure management.

"The two talks from Purdue animal scientists will revolve around the nutritive value of DDGS as affected by conditions within the ethanol plant," said Scott Radcliffe, Purdue swine nutrition specialist. "One of the unique aspects of this research was that it was done across species using the same batches of DDGS. Nutrient digestibility was investigated in swine, broilers, roosters and cattle. Growth performance and carcass characteristics were investigated in swine, broilers and sheep."

To preregister for the conference or to view the entire conference schedule, visit . The site includes a link to the preregistration page for the Webinar. Lunch, refreshments and conference materials will be provided for those who attend the conference at Beck.

For additional conference information, contact Radcliffe at (765) 496-7718 or by e-mail at ; or Ileleji at (765) 494-1198 or by e-mail at .

Writer: Steve Leer, (765) 494-8415,

Sources: Klein Ileleji, (765) 494-1198,

Richard Stroshine, (765) 494-1192,

Scott Radcliffe, (765) 496-7718,

Ag Communications: (765) 494-2722;
Beth Forbes,
Agriculture News Page

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