Scientists look for best feed from ethanol byproduct
URBANA – Ethanol is the star on the agriculture stage now, but behind the scenes, University of Illinois animal scientists are casting the spotlight on its not-so-sexy byproduct.
Distillers dried grains – or DDGs – are what's left over after distillers turn ground corn into alcohol, the hulls and other solids usually fed to livestock, especially ruminants like cattle and sheep that can digest the high fibrous feed.
UI animal scientists Larry Berger and Carl Parsons, a poultry specialist, are working on ways to make the feed more efficient and cost-effective because they say if ethanol production increases as forecast, there are going to be a lot more DDGs around.
Berger said that fact is focusing industry interest on their work.
"Forecasts say in the next couple of years, we could be fermenting up to 40 percent of the corn crop," he said. "For every bushel of corn, you get 17 pounds of DDGs. With the plants under construction in the next year or two, we could be producing 30 million tons of DDGs a year. Production's in the 10 to 12 million range now."
Berger has developed a pelletized feed for ruminants made of cornstalks treated so they're more digestible and mixed with DDGs, a study he and his students completed with major support from Decatur ethanol giant Archer Daniels Midland.
But pelletized feed is expensive, and Berger is looking for other options. He's working on a study with lambs combining chopped cornstalks and wheat straw, some treated with DDGs.
"We'll harvest stalks as silage and mix them with the DDGs at feeding time," Berger said. "We're looking for the optimum combination, digestibility similar to that of feeding them corn. They complement each other. Straw is low in protein and phosphate but high in calcium and potassium, and DDGs have little calcium and potassium but lots of protein and phosphate."
He's also working on ways to store wet DDGs at the UI's Beef Farm on Old Church Road.
"We have a trench silo, a concrete bunker, we put salt on top, 1 pound per square foot, and we put plastic over it to keep the rain off and we've stored it for a year," Berger said.
He said ruminants can eat a diet of up to 40 percent DDGs because their stomachs have bacteria designed to break down fiber; but pigs and poultry don't, so their diets typically include only about 15 percent of the byproduct.
Parsons said the ethanol byproduct has "reasonable energy value" for poultry.
"There's a lot of talk about the fiber content, but there's also a lot of fat in it," he said. "So it has energy. One of the biggest concerns in the industry is the variability in quality from plant to plant and from day to day."
Parsons is working with agricultural engineering experts to try to modify equipment so it turns out a feed product that's more consistent with a higher nutritional value for poultry.
But he said one of the biggest limiting factors to feeders is price.
"We keep hearing there's going to be a lot of it and the price will go down, but so far it's actually gone up with corn prices, " Parsons said. "And there's also geographical location. You have to pay to get the DDGs to the poultry companies.
"Turkey producers in Minnesota, where there are a lot of ethanol plants, are trying to increase the amount of DDGs in turkey feed. But there aren't many ethanol plants in North Carolina and the South so they're feeding corn and soybean meal, the diets they always use."
Berger said some new ethanol mills extract corn oil from the process to turn it into biodiesel. "That makes it even less valuable as feed for pigs and poultry because they digest oil well," he said.
Berger said DDGs that sold for $65 a ton last summer now sell for $130 a ton, following corn prices that also doubled.
"As we take more corn out of feed and use it for fuel, DDGs that used to be fed as a protein source become an energy source," he said.
Berger said talk about putting feed lots next to ethanol plants makes a lot of sense because DDGs can be trucked wet next door to feed rather than dried for shipment, a costly process that uses a lot of energy.
He said any time the product's shipped more than 100 miles, it's shipped dry because of shipping costs.
Berger is also watching the export market closely because it's expanding.
"With corn at $4, Cuba, Korea and other countries instead of importing corn to feed to livestock are importing DDGs so it's value is increased to importers," Berger said.
"It's going to be a balancing act for the next few years," he said. "We'll be operating according to supply and demand. If corn's cheap, we'll build more ethanol plants, but the cure for cheap corn is fermenting it."
"But I don't think we're going to see $2 corn for a long time."