A:   There are a few trials that suggest thiamine helps with diets high in sulfur. However, feeding thiamine will not solve all the problems. The data are inconclusive on just how big of an impact feeding thiamine has on S-induced polio. With that said, I would recommend adding thiamine at 150 to 200 mg per head daily when total S in the diet gets to 0.35% of diet DM. This assumes that the water is clean and low in sulfates. We always recommend having a fairly recent water analysis for S.

The NRC suggested maximum for dietary S is 0.4% of diet DM. We have fed diets at 0.4 and seen some cattle experience polio. Conversely, we have fed diets containing 0.5% S and not observed any polio. It appears to be sporadic when it occurs, and generally occurs when another stressor is influencing the cattle. We often observe polio soon after the grain adaptation (step-up) period is over. Another common observation is that a relatively small number of cattle will ever exhibit signs of polio (unless fed at very high levels). Another common observation with high-S diets is that intakes (DMI) will decrease.

If you have cattle with polioencephalomalacia (PEM, brainers, etc), we recommend intravenous dose of thiamine at 2000 mg. If caught early (before cattle go down), many times they will respond to the thiamine. If the cattle are not observed frequently, or you catch it after a longer period of time (many hours), then chances of recovery are much lower. It is not clear how many will die, or how they will recover.

We have much to learn about S-induced polio, but it is an important thing to be aware of and attempt to prevent.

With that said, distillers grains can vary dramatically in S content. However, most distillers grains average between 0.6 and 0.8% S. We have observed or "heard" of a range from 0.4 to 1.7% S in different loads. Assuming your water is relatively clean, and feeding a grain-based diet, you can generally feed more than 30% of the diet DM as distillers before total dietary S will approach 0.4%. Therefore, I would recommend adding thiamine when distillers grains plus solubles inclusion is 30% or more. If you are in an area with high sulfate water, then the inclusion level may be significantly less.

The key here is that is hard to develop a ration without knowing the S content of all your ingredients, as well as limiting S in the minerals you use and also analyzing the water. However, with that information, you can probably manage around this issue.