Nutritional Muscular Dystrophy / White Muscle Disease

Dietary deficiency of vitamin E and/or selenium.

Clinical signs:
White muscle disease has been reported in bison, but the clinical signs have not been described (68). In cattle, clinical signs include sudden death, increased heart rate, stiffness, weakness, recumbency, and dyspnea.

Postmortem findings:
The pathological changes associated with nutritional muscular dystrophy in bison have not been described. In cattle, the affected muscle groups can be swollen, edematous and have white or gray streaks in them. There may be cardiac hypertrophy and pulmonary emphysema (9).

In cattle, the diagnosis is made from determination of serum selenium, creatine phophokinase , glutathione peroxidase levels. Normal bison had serum selenium levels of 0.1 ug/ml. Bison from a herd with white muscle disease had serum selenium levels of 0.026 ug/ml (68). Reference serum levels of creatine phosphokinase and glutathione peroxidase have not been established for bison.

Treatment protocols for bison with nutritional muscular deficiency have not been described. Cattle are treated with selenium and DL-alpha-tocopherol injections in preparations that contain 3mg selenium per ml and 150 iu DL-alpha-tocopherol per ml. The cattle dose is 2ml per 45 kg (9). The effectiveness of this dosage has not been established for bison.
The response to treatment of severe cases will be poor. When clinical cases occur, all bison in the group should be treated, since the others in the group will probably be deficient as well. Care should be taken when handling selenium and vitamin E deficient bison because excitement or exercise may precipitate clinical cases.

Preventing the occurrence of nutritional muscular dystrophy will require supplementing the diet with vitamin E and selenium. Selenium can be toxic to cattle when overfed. It would be prudent to analyze selenium and vitamin E in feed sources, and to consult a qualified nutritionist, before supplementation is carried out. Some geographical locations are known to be selenium deficient. In these areas continuous supplementation would be required.
Selenium and DL-alpha-tocopherol can be supplemented in the salt or grain rations. Bison however, do not always consume salt or grain on a consistent basis. Bison have developed white muscle disease even when provided with free choice selenium (68). The daily requirement of selenium and DL-alpha-tocopherol for bison has not been established.


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