Maine’s state veterinarian has been working to find the source of a rare botulism outbreak that is believed to have killed 23 horses at the Whistlin’ Willows Farm in Gorham in the past month.

Part of the problem during an outbreak, says Dr. Donald Hoenig, is that once a horse exhibits signs of botulism poisoning, there is little veterinarians can do to treat the animal.

Owners of the 175-acre farm — William and Anne Kozloff, according to the Whistlin’ Willows website — did not respond Saturday to telephone calls or emails.

State inspectors believe the powerful and fast-acting neurotoxin responsible for the outbreak developed in bales of silage, which is packaged in white plastic while the grass is still moist, unlike hay, which is dried.

Hoenig said a horse can die from botulism within hours of ingestion. Flushing the animal with fluids is the standard treatment, but that is often difficult because the horse’s facial muscles are typically paralyzed and it is impossible for it to swallow.

“It is just an awful situation,” said Hoenig.

He said that antitoxins are available, but they are not a great solution since the veterinarian has to know which one of eight different strains of botulism caused the poisoning. The antidote can cost $500 to $1,000 per dose.

Hoenig said because botulism is so rare, Maine horse owners do not commonly vaccinate their animals against it. Hoenig does not recommend feeding silage to unvaccinated horses.

Hoenig said he hopes to send samples of the silage to Cornell University in Ithaca, N.Y., this week to confirm the presence of botulism. He said he would then decide what steps to take to prevent more poisonings. The person who provided the silage to Whistlin’ Willows Farm, whom Hoenig declined to identify, is working with state officials to help identify the source.

Hoenig warned horse owners against feeding moldy hay to their animals.

Some local horse owners said that while the poisonings were tragic, they were not worried about the welfare of their own animals.

Jo Hight, president of the Maine Horse Association, said silage is difficult for horses to digest and generally horse owners avoid it.

“There is no panic that this would spread,” she said.

The poisonings started April 7 and continued through April 17. Several horses recovered from the effects, probably because they ingested smaller amounts of the bacteria, said Hoenig. Another 40 to 45 horses at the farm were not sickened. Hoenig said there were no signs that the animals were cared for improperly.

There have been no other cases of suspected botulism poisonings in horses in Maine.

State officials are working with the Gorham farm owners to keep the carcasses of the animals, buried 8 feet deep on the farm, from contaminating the water table. Hoenig said the concern is not about the spread of botulism, which research shows does not spread through water, but about other contaminants.

Staff Writer Beth Quimby can be contacted at 791-6363 or at:

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