ABSTRACT: 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.