MIAMI (Reuters) - The 21 polo ponies that collapsed and died before a Florida competition this month were given a fatal overdose of the mineral selenium in a vitamin supplement, the state veterinarian said Tuesday.
A Florida pharmacy acknowledged last week it incorrectly mixed a vitamin and mineral supplement given to the horses belonging to the Venezuelan Lechuza Caracas polo team, but state officials had been awaiting toxicology tests to determine the exact cause of death.
Those tests showed "significantly increased" levels of selenium, a trace mineral essential for normal cell function but fatal in large doses, Florida State Veterinarian Thomas Holt said in his report.
"Signs exhibited by the horses and their rapid deaths were consistent with toxic doses of selenium," Holt said.
The horses collapsed at the U.S. Open Polo Championship in Wellington, Florida, on April 19.
The Lechuza team said last week its veterinarian wrote a prescription for a supplement containing vitamin B, potassium, magnesium and selenium. It said 21 horses got the injections shortly before the match and all were dead within hours, while other horses that did not get the injections remained healthy.
The horses were valued at up to $100,000 each and belonged to Lechuza Caracas owner Victor Vargas, a millionaire businessman and president of the Venezuelan Banking Association.
Holt said the findings from the state laboratory were confirmed by independent testing at three university laboratories in Florida, California and New York.
Reporting by Jane Sutton; Editing by Pascal Fletcher and John O'Callaghan