Background: Often occurs following strenuous exercise in horses that have been previously rested and are on full feed. This condition is often associated with mineral imbalances and improper nutrition, especially that of inadequate levels of selenium and the relationship of selenium intake to Vitamin E levels.
Symptoms: Stiffness of gait that may proceed to an inability to move, especially in the hindquarters. There can be profuse sweating and rapid heart rate in more severe cases.
Diagnostics: Blood tests for elevated levels of muscle enzymes; electrolyte creatinine clearance tests can indicate which minerals/electrolytes are being utilized poorly.
Special Notes: Mild cases usually resolve easily; recurring cases can be more difficult to treat.
Principles for Supplementation: Besides vitamin E and Se, calcium, phosphorus, magnesium and trace mineral imbalances account for many cases. Availability of the important minerals is questionable for many feeds and supplements currently in use.