Distillers grains energy value varies

By Ron Kotrba | July 08, 2008
Beef cattle fed a percentage of distillers grains in Nebraska performed differently than cattle fed the same percentage of distillers grains in Kansas.

This finding has driven researchers to investigate the phenomenon further, and at least two major regional differences in feeding practices have been pinpointed as the bases for these variations in beef cattle performance. The nutritional composition of distillers grains between different corn-based ethanol plants can vary, too, so when recent research at Texas A&M University, Texas Tech University and elsewhere concluded that the energy value of distillers grains is dependent on the ethanol feedstock used, it confirmed what some already believed.

Jim MacDonald, a beef nutritionist with Texas AgriLife Research in Amarillo, Texas, said two years of feeding trials on finishing beef cattle confirmed that distillers grains from
sorghum has a 25 percent lower energy value than distillers grains from corn because the energy value of the grains differs. Sorghum, used as an ethanol feedstock with corn or in rare instances as a lone feedstock, makes up only 6 percent of total U.S. ethanol production. The grain is grown in southern Plains states such as Kansas, Oklahoma and Texas.

Furthermore, there is the major difference in how cattle feeders treat feed corn as a base in which distillers grains may be added prior to cattle consumption. "Researchers in the northern Plains tend to use dry-rolled corn, and in the southern Plains, they use steam-flaked, corn-based diets," MacDonald said.

According to Terry Klopfenstein, a research professor of ruminant nutrition with the University of Nebraska, the differences in base-feed treatment are marked and have much to do with how cattle respond to the same distillers grains incorporated into the two differently treated base corn feeds. "What we know is that the cattle perform differently to distillers grains when they're fed steam-flaked corn than when they're fed dry corn," he said. "We don't know why, but that's clear. The data from Kansas State University, Oklahoma State University, Texas Tech University and Texas A&M University suggest the cattle respond differently. When I say performance,' I'm talking about rates of gain, efficiencies of gain and [maybe] differences in carcass quality."

Dry-rolled corn is gently rolled to break up the kernel for easier digestion by the rumen, whereas steam-flaked corn is steamed in a stainless steel chest for approximately 20 minutes to moisten and heat the corn up, after which it enters a roller to make thin flakes.