A new form of polio (polioencephalomalacia), resulting from cattle consuming high levels of sulfur in range situations, is hitting some cowherds hard in certain areas of the U.S. Identifying what leads to sulfur toxicity in a range scenario, and how to effectively treat, and ideally prevent, its occurrence can eliminate a costly wreck for producers in many areas.

Steve Ensley, Iowa State University veterinary toxicologist and diagnostician, says cattle consuming water with more than 1,000 ppm of sulfur are at risk to develop polio in range conditions. He suggests testing water regularly to determine the sulfur level present.

“We have some water, especially in Western states, with as much as 2,000 to 3,000 ppm of sulfur content. However, since the drinking water supply is typically limited in these situations, we have to use what is available, and cattle do consume the water without issue in some instances,” Ensley says. He stresses that while water alone can pose a problem, many cattle will consume it with no health-related issues.

Erica Koller, an Edgemont, SD-based DVM, says cattle are typically able to adjust to high sulfur content in their drinking water. What often causes them to exhibit sulfur toxicity is when a protein supplement is fed in conjunction with the water.

Ethanol-derived dried distillers grains (DDGs) is a huge byproduct used in cakes, mineral tubs and almost any other supplement that someone might use, mainly because it tends to be a cheaper, more readily available protein source. The issue is that some ethanol plants clean with sulfuric acid, and each batch of DDGs could contain anywhere from 0.4% to 1% sulfur,” she says.

With maximum diet sulfur levels for cattle suggested at 0.3-0.4%, in the right scenario, adding a supplemental feed could quickly surpass even a well-adjusted cow’s ability to avoid toxicity.

While DDGs get most of the rap for high sulfur content in livestock feedstuffs, certain plants can also contain critical levels. These include certain varieties of hay, kochia weeds and Canada thistle. Proper grazing management and testing water sources and feed additives (including hay), can help producers prevent a problem and manage around potential problem areas on their operation.

Watch for symptoms

The first sign of a problem is generally cattle exhibiting polio symptoms. Ensley says the first clinical sign to watch for is blindness. This is due to toxic levels of sulfur within the animal causing brain swelling, which damages neurons, including the optic nerves. If left untreated, ataxia, down animals and death within 48 hours of first exhibiting symptoms is the common outcome.

“An animal exhibiting symptoms can be treated with thiamin, even though the cause isn’t a direct vitamin B deficiency. Usually a combination of steroids and thiamin over 3-4 days will get the animal to come around. But, you have to get to them early, or they’ll likely die,” Koller explains.

Temporarily removing any supplements possibly containing DDGs, and switching water sources if possible, will provide immediate relief and reduce the odds of more cases. However, Koller’s strongest recommendation is to take preventive measures, rather than be prepared to treat affected animals.

Jeremy Martin, a consulting nutritionist with Great Plains Livestock Consulting Inc. in Hershey, NE, concurs. He says awareness and proper management are the most effective means of avoiding a wreck.

“If water quality is a question, you need to sample regularly – at least twice a year, in the summer and winter. I realize water testing is an expense, but with the current prices for cattle, it’s manageable in the big picture,” he states.

If water comes back high in sulfur, and no alternative water sources exist, Martin suggests producers consider how to change their feeding strategies.

“I’m not aware of anything feasible that can reduce sulfur levels in existing water sources in a ranch setting. However, it’s possible to supplement cattle to achieve similar results using low-sulfur feedstuffs. The first step is becoming more particular about the source of your protein supplement, making sure your supplier is aware of your situation, and what the sulfur levels are in their feed sources,” Martin explains.