Clinical and Pathologic Features of a Suspected Selenium Deficiency in Captive Plains Zebras

Previous studies have shown that selenium (Se) deficiency is associated with nutritional myopathy, known as white muscle disease (WMD), in horses. However, correlations between Se deficiency and clinical findings, such as hematologic biochemical values and pathological features, have not been evaluated in captive plains zebras. The purpose of the present study was to investigate the clinical and pathologic features that may be caused by a Se deficiency in the captive plains zebra. Clinical findings, feed analyses, hematologic biochemical analyses, response to treatment, and pathologic examination were assessed in six affected plains zebras. The dietary concentration of Se in feed was also tested. Sudden death occurred in two cases during the first day of the onset of symptoms. Two zebras died at 4 days and two zebras survived after treatment. The clinical signs in affected animals were characterized by general weakness, astasia, and abnormal postural positions. The Se concentration in hay from the breeding stable was low, based on the reference value. Glutathione peroxidase (GSH-Px) activity was lower compared with the equine reference value. Multiple areas of subcutaneous steatitis and pale skeletal muscle and myocardium were revealed at gross necropsy. Degeneration and necrosis of myocardial and skeletal muscles, as well as congestion of the liver, lung, and kidney were found via histopathological examination. No suspected bacterial infections were found. Feed analyses, response to treatment, serum GSH-Px activity, and pathological features suggest that Se deficiency may have caused the disease in the six affected captive plains zebra.