The Florida Department of Agriculture & Consumer Sciences released this information today:
TALLAHASSEE — Florida State Veterinarian Thomas J. Holt today reported that an overdose of selenium was the probable cause of death of the 21 polo horses that collapsed prior to a competition in Wellington on April 19.
In a memorandum to Florida Agriculture and Consumer Services Commissioner Charles H. Bronson’s office, Dr. Holt stated that the animals had “significantly increased selenium levels” in samples tested. He reported that the findings obtained at the department’s Animal Disease Diagnostic Laboratory in Kissimmee were confirmed by independent testing conducted at the University of Florida’s College of Veterinary Medicine in Gainesville, the University of California-Davis Animal Health and Food Safety lab, and at testing facilities at Cornell University in Ithaca, New York. The three universities assisted in the laboratory testing.
“Signs exhibited by the horses and their rapid deaths were consistent with toxic doses of selenium,” Dr. Holt said.
Selenium is a trace mineral which is essential for normal cell function and health in animals, and is often included in small quantities in supplements and feed for horses. Large doses, however, can be fatal to animals.
Commissioner Bronson expressed gratitude for the work done at the University of Florida, which conducted necropsies on 15 of the horses and performed extensive toxicology testing. He also thanked the University of California-Davis and Cornell University for testing conducted in their labs.
Meanwhile, Commissioner Bronson noted that the deaths of the horses have triggered an investigation by a number of state agencies, including the Department of Agriculture and Consumer Services, and he emphasized that the inquiry is ongoing.
He said that no further information on the investigation can be disclosed at this time to prevent the investigation from being compromised.