WDGS May Be High-Quality, Low-Cost Livestock Feed

Agricultural Research Service (ARS) studies have shown that "wet distiller's grain with solubles," or WDGS, may offer an inexpensive alternative to traditional feed ingredients when fed to livestock. WDGS is a common ethanol byproduct that could replace more costly traditional feed ingredients such as corn, soybean meal, urea, and mineral supplements. WDGS typically costs about 10 percent less than corn when used as livestock feed.

ARS scientists at the U.S. Meat Animal Research Center (USMARC) in Clay Center, Neb., have studied the effects of feeding WDGS to cattle. Four areas were investigated: feedlot performance, energy utilization efficiency, postharvest meat characteristics, and cattle manure emissions.

In one study, nutritionist Calvin Ferrell and food technologist Steven Shackelford monitored growth rate, feed intake, and feed efficiency for cattle in the "finishing phase"-the approximately 120 to 140 days leading up to slaughter. They found that in steers fed diets of 20 to 40 percent WDGS, performance in those areas was equal to or better than that of a group of cattle that did not receive the WDGS.

Another study, led by animal scientist Mindy Spiehs, took a closer look at feed efficiency by examining how much heat animals produced while digesting their food. Spiehs and her colleagues observed no significant difference in heat production between cattle fed 0, 20, 40, or 60 percent WDGS. But they did see lower energy utilization efficiency at the highest rate, a factor that could reduce feedlot performance.

Looking at meat quality, Shackelford, research leader Tommy Wheeler and food technologist Andy King found that feeding a diet of 20 or 40 percent WDGS produced carcasses that were the same or better for yield and quality traits than carcasses of cattle that did not eat the WDGS. Cattle fed 60 percent WDGS diets were lighter, leaner, less marbled, and had lower yield grades than cattle in the groups that consumed lower quantities of WDGS or none at all.

Microbiologist Vince Varel confirmed that as the concentration of WDGS increased in the diet, greater concentrations of nitrogen, phosphorus, and sulfur appeared in manure, mostly due to excess crude protein. Microbiologists Jim Wells and Elaine Berry also examined how WDGS diets affected persistence of E. coli bacteria in cattle feces and manure.

Read more about this research in the September 2009 issue of Agricultural Research magazine.

ARS is the principal intramural scientific research agency in the U.S. Department of Agriculture.