7/23/96

Contacts:
Allen Trenkle, Animal Science, (515) 294-4447
Ed Adcock, Agriculture Information, (515) 294-2314

EDITOR'S NOTE: The research in this release was presented in July at the annual meeting of the American Society of Animal Science.

ISU STUDY FINDS DISTILLERS GRAINS TOPS CORN FOR FEED VALUE

RAPID CITY, S.D. -- Finishing cattle benefit when fed distillers grain, a product of ethanol manufacturing, according to research at Iowa State University.

"The bottom line is that it is an excellent feed and based on the performance of cattle has a higher apparent energy value than corn," said Allen Trenkle, a distinguished professor of animal science.

Trenkle presented his research results at the annual meeting of the American Society of Animal Science, July 23-26.

Distillers grains are produced by ethanol plants when corn is converted to fuel-grade alcohol. Trenkle said distillers grains should be considered a co-product, not a byproduct, of ethanol production because of its value as a feed.

His study evaluated the performance of finishing cattle fed rations that replaced cracked corn with wet distillers grains or distillers solubles. Six diets were compared: corn and urea; corn, soybean meal and urea; corn, 6.5 percent distillers solubles and soybean meal; corn, 16 percent wet distillers grains and urea; corn and 28 percent wet distillers grains; and corn and 40 percent wet distillers grains.

"High-gain cattle need more protein," Trenkle said. "The ration with 16 percent distillers grains provided about the same protein as the soybean meal ration."

Feeding distillers solubles increased feed intake, increased gain and improved feed conversion, he said. Increasing the amount of wet distillers grains in the diets decreased feed intake and reduced gain. Feeding wet distillers grains at all levels improved feed conversion compared to cattle fed the control diet. The average net energy for gain value for wet distillers grains was 1.5 times the energy value of corn.

Economic returns declined slightly as the percentage of wet distillers grains increased in the diet, but remained above the two diets without distillers grains, he added.

"The economic advantage of including distillers grains in rations depends on the cost," Trenkle said. The price charged by the ethanol plant used in the study was a third of the price of corn purchased. Transportation costs are critical, he said, adding that finishing operations should be located within 20 miles of an ethanol plant.

Many ethanol plants use income from selling distillers grains to increase returns to the plant. Trenkle said some plants dry distillers grains to transport them long distances to dairy cattle areas for feed.

The problem with drying, he said, is that it results in a loss of feed value from solubles removed with the liquid. Researchers are unclear about the reason for the loss, but there is less energy in the dry distillers grains, resulting in a less valuable feed for finishing cattle.

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