Local polo clubs are shocked at the 21 horse deaths in Florida.

San Diego Polo Club veterinarian Dr. Michael Manno learned about the tragic situation with the horses at the U.S. Open Polo Championship in Florida as it was unfolding Sunday afternoon.

"Just in a matter of minutes, as these horses were unloaded off the truck, that they started falling to the ground," he said.

By Monday a total of 21 horses belonging to the Venezuelan-owned Lechuza polo team had died.

"For them to lose that many ponies, you can't replace them at that level of play. It's just tragedy, total tragedy," Dr. Manno said.

Alisha Wray and her husband own 16 horses, and she says she can't begin to imagine losing them all at once.

"I am sad for the entire family," she said. "We all care for our horses so much and to lose one of them is really traumatic, but to have a couple dozen within a matter of hours... it's just unbelievable."

Florida state investigators believe the horses died from some sort of reaction to toxins in their food or supplements, or possibly insect repellent. While necropsies and toxicology tests are underway, a criminal investigation has also been opened to rule out foul play.

"It's really hard for me to comprehend that anyone would intentionally try to do this. I'd have to figure out that it would have to be some sort of mistake," Dr. Manno said.

The horses that died were reportedly worth a total of more than $2 million.

The U.S. Open Polo Championship tournament will resume on Wednesday.