03/30/2006 12:00AM

Foal deaths prompt alert

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The Florida Thoroughbred Breeders and Owners Association is advising all farm owners to inspect their paddocks for caterpillars after pathologists at the University of Florida's College of Veterinary Medicine issued an alert that two recent foal deaths and a mare's late-term abortion were probably linked to mare reproductive loss syndrome.

The incidents were the first cases in Florida to be linked to mare reproductive loss syndrome, a phenomenon that has been strongly associated with the consumption of Eastern tent caterpillars. A 2002 outbreak in central Kentucky caused approximately 30 percent of mares in the region to have late-term abortions.

According to Dr. Dana Zimmel of the University of Florida College of Veterinary Medicine, pathologists believe that the death of a septic foal earlier this month was caused by the syndrome, known as MRLS. Another septic-foal death and a late-term abortion are being considered "suspect" cases pending further pathological tests, Zimmel said.

All three cases occurred in Alachua County, just north of Ocala, where the state's Thoroughbred industry is concentrated. The farms where the mares were stabled had caterpillars in the pasture, Zimmel said.

"What we don't know is whether we are seeing these cases right now because there are more caterpillars this year or because we weren't able to diagnose this in the past," Zimmel said.

State veterinary officials do not believe that the state is facing a widespread outbreak of the disease, Zimmel said.

Although no definitive cause of MRLS has yet to be discovered, veterinary officials who have studied MRLS believe that the inadvertent consumption of Eastern tent caterpillars probably causes a buildup of toxins in a mare that causes abortions within two to 10 days. The syndrome can also cause foals to be born prematurely and underweight.

Dick Hancock, the executive director of the Florida Thoroughbred Breeders and Owners Association, said Wednesday that the organization was stressing to breeders that they rid their paddocks of any caterpillars. Eastern tent caterpillars are known to favor wild cherry, apple, and crabapple trees.

"We've advised everyone to watch their paddocks and pastures, to look out for caterpillars," Hancock said. "You have to get rid of them or move the mares to other pastures. Beyond that, there's not a whole lot we can do."

The organization has also advised breeders to notify officials of any late-term abortions or foal deaths.

"At this time, we strongly recommend that all abortions and foal deaths receive a postmortem evaluation," the organization said in a health advisory issued on Wednesday.