Sulfur (S) intake does not appear to be the only factor contributing to the likelihood of S-induced polioencephalomalacia (PEM). Cattle appear to be more susceptible during the early part of the finishing period. In this study, increasing S inclusion after the first 30 d of finishing resulted in lower peak hydrogen sulfide (H2S) concentrations compared with feeding the same level of S earlier in the finishing period. Therefore, waiting to include high levels of ethanol co-products until after the first 30 d of finishing may decrease the likelihood of S toxicity.