The veterinarian’s diagnosis was polioencepholomalacia or PEM. The condition is also referred to as brainers. PEM is a noninfectious neurological disease that is related to thiamine deficiency.
“The cause of the deficiency is not always clear, but does seem related to abrupt ration changes. High sulfur levels in the feed and water are also implicated,” said Eldon Cole, livestock specialist with University of Missouri Extension.
The symptoms are many and varied. They may include restlessness, diarrhea, muscular twitching, hard breathing, blindness or star gazing and circling. Death may occur if not treated promptly.
The ration being fed in this recently struck herd did include several by-product feeds that could potentially contain high levels of sulfur according to Cole.
“Those products included corn gluten feed, dried distillers grain and condensed distillers solubles; the latter feed is called "syrup."
Recommendations for sulfur levels in cattle diets are placed at no more than 0.4 percent of diet dry matter. The average sulfur content of the three by-products, according to the book values, should be safe, but borderline.
“Unfortunately, by-product feeds vary tremendously in their nutritive values. The sulfur values on these feeds may run from 0.4 percent up to one percent, or more on a dry matter basis. I’ve even seen syrup sulfur levels above 1.5 percent,” said Cole.
When cattle are fed other low sulfur feeds such as pasture and the by-products make up no more than 0.5 percent to one percent of the animal’s body weight, Cole says there should be minimal risk of PEM.
Certain water supplies may also contain high sulfur levels which can add to the PEM possibilities.
“The bottom line is to know sulfur levels in your feeds if possible and not overdo a good thing when there’s a chance it could cause problems,” said Cole.
Many cattle have been fed three to five pounds of corn gluten feed and other untested by-products per head, per day, with no reported instances of PEM.
“As we see more ethanol by-products such as distillers grain and syrup available in southwest Missouri, use them according to recommendations. Too much of a good thing could be bad,” said Cole.