Nutritional deficiencies of vitamin E and selenium can occur alone or concurrently. Prolonged and sustained deficiency of either or both nutrients can lead to profound clinical disease. Selenium deficiency can also result in signs of cardiac disease, upper gastrointestinal dysfunction, and abortion or the birth of weak foals. Deficiencies can usually be readily established by evaluating the dietary intake of individuals and by measurement of blood concentrations of these nutrients. Treatment of clinical disease is not always successful and prolonged morbidity and mortality can be encountered
hence, prevention is of the utmost importance.