Selenium Likely Cause of Polo Horses Deaths

MIAMI—An overdose of selenium was the likely cause of death for the 21 polo horses from Venezuela's Lechuza Caracas team at the U.S. Polo Championships, according to Florida state investigators and the Ocala, Fla-based pharmacy that produced the supplement. The toxicology reports showed fatal amounts of selenium in all of the horses that perished on April 19 and the Franck's Pharmacy confirmed they prepared a supplement that contain an incorrect dose of selenium.

The supplement was designed to mimic Biodyl, a equine product manufactured in France, but not approved in the United states. Biodyl contains selenium, magnesium, Vitamin B and potassium.