Industry under threat after MRLS kills two foals in Florida.

Byline: By Amy Bennett

THE cause of death of two foals in Florida in the last fortnight has been confirmed as mare reproductive loss syndrome (MRLS) - the destructive condition that caused havoc in the bloodstock industry's Kentucky heartland five years ago.

The first foal, a thoroughbred, was out of a mare from the University of Florida's research herd, while the second was a quarter-horse foal, born at a private farm in nearby Alachua County.

MRLS, which causes mares to abort and can lead to eye, heart and respiratory illnesses in foals, had a devastating impact during a severe outbreak in Kentucky in the spring of 2001.

A study commissioned by the office of Kentucky Governor Paul Patton showed that MRLS resulted in the loss of 516 foals in 2001 and 2,998 of the 2002 foal crop, a loss of 30 per cent of the 2002 crop.

The financial loss at the time was estimated to be as high as $400 million, with returns at yearling sales dropping from $473.3m in 2001 to $390.8m in 2002. Two more cases of MRLS are suspected in Florida.

While no definitive cause of MRLS has been pinpointed, the syndrome is widely believed to be caused by mares ingesting eastern tent caterpillars while grazing. Large numbers of the caterpillars, which feed primarily on cherry trees, were noted in Kentucky during 2001 following an unusually warm spring. Farm owners have since cut down many of the cherry trees that were home to the caterpillars.

The caterpillars have been much in evidence in Alachua County this year, and stud owners are now being advised to clear their fields of the insects.

Richard Hancock, vice-president of the Florida Thoroughbred Breeders' and Owners' Association, told the Thoroughbred Times: "We understand the importance of the situation and are working closely with our state and local vets. The main thing is to get the caterpillars off the pastures.

Bloodstock Desk, page 18