Contaminated Hay Blamed for Mystery Horse Deaths

State agriculture officials Wednesday blamed hay cubes contaminated with a botulism bacteria for the mystifying deaths of at least 15 horses in stables across Southern California over the past two weeks.

Laboratory tests confirmed that from two to three pounds of the candy bar-sized cubes, collected at a San Bernardino County stable where three horses died, contained remains of a rabbit that may have carried the bacteria, officials said in a news conference at the Orange County Fairgrounds Equestrian Center in Costa Mesa.

It was there that the puzzling malady came to light Oct. 28, and in the space of a few days claimed the lives of seven horses. Two other horses at the center have been stricken with similar symptoms--quivering muscles, difficulty breathing and dull eyes--but remained alive Wednesday night.

State officials and local veterinarians, encouraged that no new cases have been reported since Tuesday, expressed optimism that the crisis that had alarmed stable owners and equestrians has ended.

“Each day that passes with no reports of new victims is a positive sign that we may have isolated the problem,” said Irvine veterinarian John Byrd, who treated the sick horses at the Costa Mesa equestrian center. “For the first time in a week, we’re feeling better.”

In all, officials said that 15 horses have died--seven in Orange County, three in Chino, three in Los Angeles County and two in Ventura County.

Investigators focused on the possibility of botulism after eliminating other potential culprits such as rabies, strychnine, heavy metals, pesticides or infectious viruses.

Dennis Thompson, a state Department of Food and Agriculture veterinarian, said hay cubes had been fed to each of the afflicted horses.

Early on, veterinarians had suspected botulism, a type of food poisoning. But it was not confirmed until cubes from the Prado Park Stables in Chino were analyzed and animal remains were found.

The tainted cubes, Thompson said, were processed in Utah, where the hay was cut and then compressed into pellets by a harvesting combine. Thompson said the rabbit may have been caught in the harvesting machinery, then shredded and pressed into the cubes.