Case report - Sulfur-induced polioencephalomalacia in beef steers consuming high sulfate water

Central nervous system disease occurred in a group of beef steers placed into confinement feeding pens during a period of prolonged drought and high environmental temperatures. The steers began exhibiting neurological signs during the third week after placement into the pens. Microscopic examination of brain tissue revealed lesions consistent with polioencephalomalacia. Tissue analysis for lead and evidence of water deprivation-sodium ion toxicity were negative. The steers had been drinking well water containing 3000 ppm sulfate. In addition, the total mixed ration contained 2950 ppm total sulfur. Total sulfur intake was calculated to be 77 grams of sulfur per steer per day, which equated to 1% (10,000 ppm) of the ration on a dry matter basis. Based upon clinical signs, histopathology and high levels of sulfate and sulfur in the water and feed, respectively, a diagnosis of sulfur-induced polioencephalomalacia was made. No further cases occurred after the steers were provided water with low sulfate content.