Determining the Influence of Dietary Roughage Concentration and Source on Rumen Parameters related to Sulfur Toxicity

Producers are looking for a way to prevent the negative effects associated with feeding large amounts of ethanol co-products that are high in sulfur (S). High levels of S in the diet result in increased ruminal concentrations of hydrogen sulfide (H2S). Elevated levels of ruminal H2S have been correlated to increased incidences of the neurological disorder polioencephalomalcia. The results of these studies suggest that when balanced for NDF levels, chopped cornstalks and chopped bromegrass grass hay did not differ in their effects on rumen H2S concentrations and ruminal pH, and that increasing inclusion of roughage resulted in increased ruminal pH and decreased ruminal H2S. Although increasing roughage levels in the diet results in reduced energy density of the diet, steers in this study increased intake to compensate and thus gains were not affected. Increasing hay inclusion in the diet from 5% to 12% (DM basis) decreased H2S concentrations by approximately 2,000 ppm, and thus appears to be a practical way to increase inclusion of high S ingredients such as ethanol co-products while reducing the risk of S toxicity