The postmortem testing conducted by the University of Florida College of Veterinary Medicine pathologist and toxicologists on a group of prized polo horses that collapsed and died April 19 revealed answers.

The answer to the horse mystery concluded when on April 22 toxicologists said the horses had been given an incorrect dose of the ingredients used in a vitamin compound.

Blood tissues and samples were initially gathered from the 15 horses but nothing was evident when the UF pathologists conducted necropsies, according to the UF College of Veterinary Medicine.

Tests conducted by Dr. David Barber, an associate professor in the Center for Environment and Human Toxicology in the college's department of physiological sciences verified the presence of life-threatening concentrations of selenium in the horse's blood and liver samples.

The samples were 10 to 15 times higher than normal in the blood and 15 to 20 times higher than normal in the liver.

The selenium was the incorrect dose in the vitamin compound, said Barber.