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Q: What is an acceptable level of sulfur in finishing cattle diets containing distillers' grains to reduce concerns of polio?

A: The answer to that question is an open ended one. It really depends on the feeding situation and other sources of sulfur. Because sulfur levels in distillers' grains can vary from day to day even within the same plant, taking the average sulfur content and formulating rations based on that may cause problems. The NRC estimated the maximum tolerable dietary concentration of sulfur to be 0.4% of the diet dry matter. There have been cases where more sulfur has been fed, but usually the roughage level in the diet is increased to reduce the possibility of development of sulfur-induced polio. The incidence of sulfur-induced polio in some cases appears to be related to a stressful event such as a weather change or muddy conditions. With this in mind, some people will step-up the level of distillers' grains in the ration if it is high in the final ration (i.e. 25% or more distillers' grains, depending on the concentration of sulfur in the distillers' grains). Receiving can be a stressful time for cattle and there may be some adaption of the rumen environment to high sulfur levels. Another concern is water quality, and this is especially important in the summer when water intake is high. If water sulfate levels are 1000 ppm, when the ambient temperature is 40º F the sulfur intake through water will be approximately equal to an additional 0.10% dietary sulfur. However, when the ambient temperature is 90º F the sulfur intake through water will be approximately equal to an additional 0.23% dietary sulfur. Variability of sulfur in content of distillers' grains will also have an impact on how much can be fed. A lot of polio problems can be attributed to an unexpected load of high sulfur distillers' grains. Sulfur levels can vary due to additional sulfur being used in the process of making ethanol. Differences in sulfur content of distillers' grains can also be the result of varying levels of distillers' solubles (i.e. syrup) being added back onto the distillers' grains. Sulfur levels can be almost 1.0% greater in the distillers' solubles than in the distillers' grains. A fairly safe and practical recommendation for sulfur levels in feedlot diets where water quality is not an issue is 0.30% of the diet dry matter. The best suggestion I can give you though is to work with a nutritionist to assess your particular situation and design a ration that will suit your operation.