The horses, worth up to $1.5 million, belonged to a Venezuelan team, Lechuza Caracas. They reportedly appeared dizzy and disoriented while being unloaded from their trailers Sunday afternoon just prior to a 3 p.m. match. Seven died at the scene, and the others during treatment elsewhere or while being moved to a medical facility.
"Some died right away. Others lasted about 45 minutes," said Dr. Scott Swerdin, of the Palm Beach Equine Clinic, International Polo's consulting veterinarian group, who was at the scene.
Eyewitnesses said several veterinarians from Wellington, a wealthy equestrian and golfing community in central Palm Beach County that hosts the event every year, rushed to the grounds to help try to revive and save some of the horses by running cold water on them and using fans that shoot a fine water mist to try to get their body temperatures down. Intravenous tubes were inserted to help them breathe.
Large blue curtain screens were put around the horses to shield them from direct view of the audience.
Another veterinarian at the scene, Dr. James Belden, told NBC's "Today" show Monday morning it appeared some type of poison was to blame and could have led to what he believes was heart failure among the horses. "Well, clearly it's an intoxication, clearly there's some sort of poison," he said during the telecast, adding that it remains to be seen "whether it's something in the environment or something that the horses were exposed to." He said the horses followed a normal routine in the stable before the match.
"It could be the water, hay, bedding. We just don't know. When we find out what it is, we will take all the necessary actions," said John A. Wash, a polo club official.
Necropsies were being conducted by State Veterinarian Dr. Mike Scott at the state-run Kissimmee Diagnostic facility. A preliminary report was expected late Monday or sometime Tuesday.
After the incident, an exhibition match replaced the match in which the fallen horses were to have participated. Each 10 or 11 years old, the horses were said to be worth about $100,000 each.
The U.S. Polo Association, the sport's governing body, said it also plans a full-scale investigation.