(Editor’s note: This story updates an earlier version which did not yet have the name of the stable involved.)

GORHAM – According to Maine State Veterinarian Dr. Donald Hoenig, 23 horses have died since Easter at the Whistlin’ Willows Farm on Nonesuch Road in Gorham.

In a telephone interview Friday, Hoenig said all 23 horses either died or were euthanized by local veterinarians after succumbing to symptoms of botulism.

Hoening said the horses appear to have contracted the toxin from balage – a method of gathering chopped hay or plant material into large, round bales and sealing them in container, usually by wrapping them in plastic, at a high moisture content, to increase forage value per acre.

“We know they were fed both balage and dried hay,” said Heonig. “The balage is where we are focusing right now.”

The state has contracted the feed supplier, said Hoenig. He declined to release the name of that company because, “We don’t think we know everything we need to know just yet.

“We are right in the midst of the investigation, so we want to make sure we have all of the facts straight,” said Hoenig.

Hoenig said there appears to be “very little” danger to other area stables. Still, because botulism is “very hard to test for,” he cautioned similar operations from using balage.

“It’s not really a good practice to feed balage to horses because of the possibility of botulism,” he said.

State officials, who were at the Gorham farm as recently as Friday afternoon, are scheduled to return next week. The stable has changed the feed it’s using and no additional horse have become sick in the past few days, said Hoenig. The state’s primary concern at this time is the mass burial ground, located alongside a barn.

“It’s not a dire emergency, but we’ve got to get them out of there and buried according to our carcass-disposal guidelines in a fairly short period of time,” said Hoenig, citing possible groundwater contamination. “We’re just trying to determined to what steps we can take to make sure that happens in a fairly quick period of time.”

Hoenig said he was not certain how many of the dead horses were owned by the stable and how many, if any, were boarders.

Stable owners William and Anna Kozloff could not be reached for comment Friday. The website for their 175-acre farms says it is home to “over 50 horses,” meaning it has lost almost half of its stock since the first reported death on April 7.