A Florida pharmacy says that medication that it prepared for 21 polo horses that died at a Florida tournament over the weekend contained the incorrect dosage of an ingredient.
Jennifer Beckett, the chief operating officer of Franck's Pharmacy, said in a statement that an internal company investigation found that "the strength of an ingredient in the medication was incorrect." The statement did not name the ingredient.
The horses, from Venezuela's Lechuza Caracas team, began collapsing Sunday afternoon as they were unloaded from trailers at the International Polo Club Palm Beach, in Wellington, Fla., where they were scheduled to play in the U.S. Polo Open.
The cause of their death is currently under investigation by local and state officials, and Beckett's statement said the pharmacy is cooperating with the investigation.
The statement said the pharmacy prepared the medication on order from a Florida veterinarian, who was not named.
Lechuza Polo said in a statement that a Florida-licensed veterinarian wrote a prescription for the pharmacy to create a compound similar to Biodyl, a vitamin and mineral supplement that is not approved for use in the United States. The supplement is often used to treat fatigue in horses.
"Only horses treated with the compound became sick and died within three hours of treatment," the team said in the statement. "Other horses that were not treated remain healthy and normal."
The statement said the Biodyl compound contained vitamin B, potassium, magnesium and selenium.
Dr. Luis Castro, a Florida equine veterinarian, said high levels of selenium or potassium can kill horses.
"Lower levels of selenium have been known to kill horses, once in a while it happens," he said. "If you multiply that by whatever mistake was made, obviously you're going to have a big problem on your hands."
Castro said the pharmacy, Franck's, had a very good reputation among veterinarians. "It's very tragic that they're involved in this," he said.
State veterinarians are still running tests to determine what killed the horses.
Veterinarians who treated some of the animals, worth roughly $100,000 each, said Monday they believed the horses were probably killed by some sort of toxin in their feed or vitamin supplements.
"We want to get to the bottom of this and find out what happened," said Peter Rizzo, director of the U.S. Polo Association.
A Department of Agriculture spokesman said earlier this week that there was nothing to indicate that the horses were intentionally poisoned.
"We want to make sure that there were no violations of Florida law in connection with anything these animals were fed or administered injection-wise," said Terence McElroy, a spokesman for the Department of Agriculture.
McElroy said the inquiry would look into animal mistreatment laws and make sure the horses were not given narcotics and were not prescribed any chemicals by anyone other than a licensed veterinarian.
"We just want to find out what happened to the horses," said Capt. Greg Richter of the Palm Beach County Sheriff's Office. "At this point, there's nothing to indicate any criminal intent or wrongdoing."
The horses were reportedly showing no signs of illness Sunday morning, according to the Department of Agriculture. By the time they were offloaded for the match, some of the animals were dead and the rest were showing signs of dizziness and having trouble breathing.
Scott Swerdlin, one of the veterinarians who treated the horses, said on Monday they died after they developed pulmonary edema, a buildup of fluid in the lungs, which sent them into shock.
"I've never seen anything like this," Swerdlin said. "Not only is it frustrating, it's tragic. We're emotionally drained too. It was just horrible."
Rob Boswell, another veterinarian at the Palm Beach Equine Clinic near the polo club, who did not treat the horses, also said "a toxic substance would be very high on your list" of possible causes of death.