Case Report: Polioencephalomalacia in Dairy Calves

Polioencephalomalacia (PEM) is a neurologic condition in ruminants that can be caused by several dietary factors including water deprivation-sodium ion toxicosis, lead poisoning and high sulfur intake. Three month old calves on a 1500-cow dairy experienced neurologic problems during three separate episodes. The morbidity rate approached 75% each time. Based upon post-mortem examination, three of the affected calves were diagnosed with PEM. The history revealed a change in the formulation of the pelleted feed four day prior to the initial outbreak.

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The Relationship between Sulfer, Thiamine and Polioencephalomalacia

Thiamine deficiency has been classically described as the cause of ruminant polioencephalomalacia (PEM). More recently excess dietary sulfur has been shown to be a major cause of PEM. This paper reviews the relationship between PEM and thiamine metabolism in mature cattle, thiaminase in plants, rumen acidosis and excess dietary sulfur.

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Sulfur Toxicity - Polio in Cattle can be Caused by Sulfur Toxicity

Polioencephalomalacia (PEM) was first reported in 1956 and was described as a neurologic disorder of cattle characterized by blindness, ataxia, recumbancy and seizures. The micropathologic description was a laminar cortical necrosis. This description of PEM is still accurate 50 years later, but several additional causes have been identified.

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