Mysterious ailment is killing foals and triggering abortions


LEXINGTON, Ky. – Horse breeders are facing what may be the most devastating reproductive disaster in recent industry history.

As of May 14, 442 aborted equine fetuses and stillborn foals have been submitted to the University of Kentucky Livestock Disease Diagnostic Center since April 28. At least 18 breeds have been affected, but 70 percent of the total loss in Kentucky has been Thoroughbreds.

Although central Kentucky farms are at the epicenter of the foal loss crisis, losses have also been recorded in Ohio, Pennsylvania, Indiana and Illinois.

Undetermined cause.

The cause of the mare reproductive loss syndrome has not yet been determined, but research shows a possible link to fescue mycotoxins.

Reports show the syndrome could have a $150 million impact on Kentucky’s economy. Many mares are having late-term abortions and cannot be bred for another 120 days.

“The problem has been devastating. It appears to be pasture related and not contagious,” said Rusty Ford, Kentucky Department of Agriculture’s equine program manager. “The mycotoxin theory is so far the most defined conclusion. We have ruled out any viral agent. It’s definitely an environmental issue.”

Horse owners are reporting two problems. One problem is a significant amount of late-term abortions and foals being born weak. Ninety percent of the affected foals born alive will die within days.

Symptoms in mares include nonproduction of milk, difficulty giving birth, and stillborn fetuses.

Another problem is an increased number of mares determined to be pregnant at about 40 days, but then experiencing early fetal loss. Affected mares seem normal during manual pregnancy examinations, but during ultrasound tests an abnormal fluid is seen around the fetus.

More than one-third of this season’s foals have been aborted in Kentucky.

“This problem involves many breeds and farms,” said David Powell, disease researcher with the University of Kentucky’s Maxwell Gluck Equine Research Center.

“The problem does not appear to be contagious – that is, spread by one horse coming into contact with another horse.”

Ohio losses.

After noticing problems with his clients’ foaling mares, Richard Novak, a veterinarian in Novelty, Ohio, attended the Late Term Abortions and Early Fetal Loss Information Session May 10 in Lexington, Ky.

Novak said the late, wet summer, severe winter, and warm spring days coupled with cold, frosty nights allowed a mold to grow on the pasture.

“At the meeting we were told information could change hourly because they’re (researchers) are working around the clock running tests,” said Novak. “The researchers I met at the meeting were obviously stressed and hadn’t slept more than two hours a night for a week.”


Novak said mycotoxin binders seem to be the only answer to battle the foal loss syndrome. The supplements bind mycotoxins in the animal’s digestive tract, preventing those toxins from being absorbed.

“Keeping the horses out of pasture is not the answer. It comes down to 30 cents a day to feed the supplement to neutralize the toxin,” said Novak. “It was reported at the meeting, that within two days of availability, every broodmare in Kentucky was getting this supplement. Feed companies are having a hard time keeping it in stock.”

Novak has seen three farms in Ohio and western Pennsylvania with disastrous problems. One Pennsylvania farm lost all 16 of its foals.

There have also been reports of foal loss in Morgan, Highland and Gallia counties in Ohio. Veterinarians are reporting an abnormal number of red bag abortions in ponies, Standardbreds and Quarter Horses.

Modroo Farms in Chagrin Falls, Ohio, lost two foals this season.

“After we lost the first foal, our vet sent tissue to a lab to rule out any normal viruses and the results did show high levels of fescue toxicity,” said Mary Hardy. “We put the remaining mares on Domperidone (a medication used to counteract the problems associated with fescue toxicosis) and they foaled without any problems.”

The Ohio Department of Agriculture’s Animal Disease Diagnostic Laboratory reports no increase of early fetal abortions from last year.

“Last year to this date we had 21 fetuses submitted for examination. From January 2001 to now, we have had 17. We are aware and alert to the situation in Kentucky, but so far have not seen an increase,” said lab spokesman Sheila Grimes.

Similar loss in ’81.

Novak said a similar incidence of foal loss happened in 1981.

“In 1981, we lost an abnormal number of foals. There are definite parallels. Researchers are going to study the environmental history to see if the two problems could be related,” said Novak.

Horse owners are encouraged to report late-term abortions or similar problems. Veterinarians are being advised to consider ultrasounding mares at 60-65 days of gestation. If the mare aborts, fetal tissue and a serum sample should be submitted to the UK Livestock Disease Diagnostic Center.

For information contact the UK Livestock Disease Diagnostic Center, 1429 Newtown Pike, Lexington, KY 40511-3186 or call Bob Coleman at 859-257-9451. Information is also available on the University of Kentucky’s College of Agriculture Web site:

(Reporter Annie Santoro can be reached at 1-800-837-3419, ext. 22, or

Get our Top Stories in Your Inbox

Next step: Check your inbox to confirm your subscription.