CANYON -- Wet sorghum distiller's grains can be fed in a steam-flaked corn ration without affecting efficiencies, said two researchers.
The two four-month cattle finishing experiments with yearling heifers were conducted by Dr. Mike Brown, a Texas Agricultural Experiment Station ruminant nutritionist and West Texas A&M University associate professor, and Dr. Andy Cole, U.S. Department of Agriculture-Agricultural Research Service animal scientist.
Designed to gain more information on the feeding value of wet sorghum distiller's grains plus solubles, the study included 400 head of cattle. These cattle were divided between two study periods, April 27-Aug.14 and July 28-Dec. 8; with eight replications of five treatments, Brown said.
"We wanted to determine what the trade-off is when you substitute wet distiller's grains for some of the steam-flaked corn and cottonseed meal," Brown said. "Also, there hadn't been any studies previously to assess the value of the fat within the distiller's grains."
Two of the treatments were standardized, based on steam-flaked corn diets with no wet distiller's grains, while three of the diets had 15 percent of the ration dry matter as wet sorghum distiller's grains. The distiller's grains replaced a combination of 35 percent cottonseed meal and 65 percent steam-flaked corn, he said.
Yellow grease was added to the steam-flaked corn diets as a fat source because the distiller's grains have a higher fat content than the original grain, Cole said. The energy-dense fat helps tie the ration together, making it less dusty.
In the long run, with 8 percent to 10 percent fat, wet distiller's grains have a number of advantages over dried distiller's grains, including greater nutritive value and elimination of the added expense of drying, he said. However, the disadvantage is hauling the water, so they must be from a local source.
Within the study, heifers receiving the wet distiller's grains and solubles ate about 5 percent more and gained about 5 percent more, so the feed efficiency was the same in comparison to those that did not receive it, Brown said.
"We found you will have to have one and a half percent added fat with the distiller's grains to achieve the feed efficiency similar to a steam-flaked corn diet with 3 percent fat added," he said.
The net energy value for gain of the distiller's grain based on animal performance was 80 percent of that used for steam-flaking corn, Brown said. Those numbers determine what the exchange is, or what the nutritive values are for competing ingredients,
Nutritionists and feedyard managers can factor in costs û the price of distiller's grains, cottonseed meal, yellow grease, which all change over time û to determine what is more economical, Cole said.
"Through the comparison of with or without distiller's grains, we have numbers of what actual performance ended up being with those exchanges," Brown said. "Individuals can use that information and apply economics to it to find the best combination of ration ingredients at a given point of time."
Another consideration in feeding a wet distiller's grain is the ration has more total weight to be delivered to the bunk, he said.
"We measured diet density on six occasions to determine if you have to haul more or fewer loads to feed the cattle," Brown said. "That would certainly factor into decisions at a commercial facility."
The distiller's grains rations were wetter and more dense than those without distiller's grains, he said. The data suggests a feedlot would need to deliver 10 percent more feed if feed trucks are filled to the same volume or 23 percent more if feed trucks are filled to the same total weight.
The researchers also are looking at potential effects on ammonia emissions and other environmental and animal health concerns, Cole said.
"We certainly didn't see any adverse consequences at the feeding rate of distiller's that we used," Brown said, but added the environmental data is still being analyzed.