05/20/2001 11:00PM

USDA to assist in survey on mares

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LEXINGTON, Ky. - As veterinarians and researchers continue to seek a definitive cause for the disease that is making Kentucky's mares abort their foals and fetuses, three United States Department of Agriculture veterinarians will help Gluck Equine Research Center officials design a second questionnaire for Kentucky's farm managers.

The Kentucky Thoroughbred Farm Managers Club and Kentucky Association of Equine Practitioners sent an initial questionnaire to 159 area farms last week.

According to a statement issued by the University of Kentucky's communications director, Dr. Carla Craycraft, the new epidemiological survey will address such issues as breed differences, mowing patterns, fertilization patterns, pasture management, pasture composition, and horse management on both infected and uninfected farms.

Researchers have yet to identify the disease's cause, but they believe the problem may be related to toxins in the pasture where horses eat.

The investigation is being focused on ergot alkaloids produced by fungi in the grass; a range of mold- or fungus-produced mycotoxins; and plant-produced estrogens, as well as other compounds affecting pasture grasses.

From April 28 through noon on Tuesday, the University of Kentucky's Livestock Disease Diagnostic Center in Lexington reported it had received 468 aborted or stillborn foals and/or fetuses thought to have been killed by the disease.

In the first week of May, veterinary researchers also began discovering that many newly pregnant mares were aborting their early-term fetuses between 40 and 85 days after conception; the most recent numbers available, from May 8, put those losses at 678 fetuses, but the number is thought to be far higher now.

Veterinarians continue to advise clients to provide their horses feed supplements that include mycotoxin binders, which are designed to neutralize the toxins, and to mow pastures low enough to eliminate seed heads but not so low as to discourage pasture growth.

They also have recommended administering domperidone, which is thought to be effective against mycotoxins, to mares late in pregnancy.

The KAEP also is asking vets to collect manure samples from mares and deliver them frozen to Dr. Kyle Newman at the Livestock Disease Diagnostic Center for testing.

Samples should include the date, mare's name, farm, veterinarian, and a brief history of the mare, including the brand names of any medications and supplements the mares have ingested.