High-sulfur in beef cattle diets: a review

While many cattle feeding areas in the United States have long dealt with high sulfate water, increased feeding of ethanol coproducts such as distillers grains with solubles to beef cattle has led to a corresponding increase in dietary sulfur. As a result, sulfur metabolism in the ruminant has been the focus of many research studies over the past 10 yr, and advances in our knowledge have been made. Excessive sulfur in cattle diets may have implications on trace mineral absorption, dry matter intake, and overall cattle growth. This review will focus on what we have learned about the metabolism of sulfur in the ruminant, including ruminal sulfate reducing bacteria, the role of ruminally available sulfur, factors affecting the production of hydrogen sulfide in the rumen, and the potential mechanisms behind sulfur toxicity in cattle. Additionally, this review will discuss potential strategies to minimize risk of sulfur toxicity when cattle are fed high-sulfur diets, including dietary and management strategies. Further research related to high-sulfur diets including implications for carcass characteristics, meat quality, and animal health will also be discussed. As ethanol production processes continue to change, the nutrient profile of the resulting coproducts will as well. Often removal of one nutrient such as oil will result in the concentration of other nutrients such as sulfur. Therefore, it seems even more likely that a better understanding of sulfur metabolism in the ruminant will be important to beef cattle feeding in the future.