Cattle Polioencephalomalacia Prevention: Sulphur Monitoring in Feedlots

Monitoring dietary sulphur to prevent polioencephalomalacia in feedlot cattle is a critical welfare and management intervention that requires understanding multiple sulphur sources.

Key Facts

Dietary sulphur above 0.3-0.4% dry matter increases risk of PEM by impairing thiamine metabolism and producing hydrogen sulphide gas in the rumen
Water sulphate is a frequently overlooked source — water with over 500 ppm sulphate contributes significantly to total dietary sulphur
By-product feeds including distillers grains, corn gluten feed, and beet pulp can be high in sulphur — up to 0.8-1.0% DM
Hydrogen sulphide produced in the rumen of cattle on high-sulphur diets is absorbed and damages brain tissue
Total dietary sulphur should be calculated accounting for feed, water, and mineral sources combined
Early neurological signs — blindness, head pressing, unresponsiveness — indicate established PEM requiring immediate thiamine treatment

Welfare Considerations

Polioencephalomalacia caused by dietary sulphur excess is an entirely preventable welfare emergency. The neurological deterioration — blindness, seizures, recumbency — represents severe acute suffering. Prevention through sulphur monitoring is straightforward but requires measuring all sources: feed ingredients, water, and mineral supplements together. Feedlot nutritionists who routinely calculate total dietary sulphur can keep rations within safe thresholds. Water testing is particularly important in areas with naturally high sulphate levels. The rapid response of early-stage PEM to thiamine injection makes quick recognition and treatment the key to minimising suffering once disease occurs. Training feedlot staff to recognise early neurological signs enables faster intervention before cases become irreversible.

What You Can Do

Test water sources for sulphate annually — particularly wells and surface water in areas with high mineral content
Calculate total dietary sulphur when formulating rations including all by-product feeds, water, and mineral contributions
Keep total dietary sulphur below 0.3% DM for feedlot cattle and monitor by-product feed composition from variable sources
Train feedlot staff to recognise early PEM signs and ensure emergency thiamine is available on-farm
Consult a ruminant nutritionist when incorporating high-sulphur by-products into feedlot rations