NASHVILLE, Tenn. -- In the beef safety section of Cattlemen’s College at the National Cattlemen’s Beef Association annual convention Feb. 1, the link between Escherichia coli O157:H7 and the feeding of wet distiller’s grains (WDGS) was discussed. 

Meat Animal Research Center researcher Elaine Berry, PhD, outlined studies looking at different levels of WDGS in growing and finishing diets and the effect on E. coli prevalence in hides and fecal matter.

Berry said in one study where controls were fed no WDGS in the ration and others were fed 40% WDGS, fecal samples during finishing in the controls was 1.5% versus 15% positive samples in the 40% WDGS group.

Hide samples were similar in that 33% of the cattle fed 40% WDGS were positive for E. coli on the hide, versus 9% in the controls.

“High WDGS levels in the finishing diets did increase E. coli O157:H7,” Berry said.  “This indicates mechanisms by which E. coli increases, and may point to potential control points.”

She said, however, that eliminating WDGS is not the goal, but rather “can we reduce E. coli when feeding? Can we feed WDGS initially and then remove it from the diet before finishing?”

Another study was done to determine just that.

Cattle were fed a silage-based growing diets with WDGS included at none, 40% and 70%. After the growing phase of 56 days the percentage of WDGS in the diet was reduced to none, 15% or 40%, and the cattle were fed another 56 days.

At finishing, fecal samples showed that the  WDGS-free controls were 2% positive; the 40% group was 35% positive; and the original 70% group was 38% positive.

“The treatment group maintained on the 40% WDGS had higher levels than animals fed no WDGS, and when shifted from the higher diet to the lower diet, that group shifted significantly lower. Hide contamination was significantly higher in the 40% WDGS group than the controls, Berry said.

“Feeding high levels of 40% and 70% WDGS can increase E. coli prevalence in feces and hides,” she said. “But reducing the amount fed as well as the timeframe may reduce E. coli."