Myeloencephalopathy, Equine Degenerative
Basic Information
Epidemiology
Risk Factors
• Prolonged exposure to dry dirt lots with no grass.
• Feeding of heated, pelleted feed and sun-baked forages with very low vitamin E content (<5 U/kg dry matter).
• A familial tendency has been observed, suggesting vitamin E deficiency has a greater effect in genetically predisposed animals.
• Some chronically affected animals have been found to have normal serum vitamin E concentrations because of subsequent pasture exposure.
• Use of insecticide and exposure to wood preservative has been identified (with others) as risk factors in equine degenerative myeloencephalopathy (EDM), although a causal relationship has not been established.
Clinical Presentation
History, Chief Complaint
• Signs are first seen in suckling and weanling foals younger than 6 months.
• Signs are usually insidious in onset and slowly progressive. However, an acute onset of severe ataxia and weakness in the pelvis or all four limbs may occur.
• Clinical signs occasionally progress to recumbency, although most frequently the clinical signs plateau with maturity of the horse and chronicity of the condition.