The cases of mare reproductive loss syndrome (MRLS) that Lexington, Ky., experienced in 2001 were a symptom of many issues converging, according to laboratory medicine specialist Jennifer Taylor of Melbourne, Australia. Taylor presented her findings in a seminar at the University of Kentucky's Gluck Equine Research Center on June 30.

"This type of abortion happens all over the world and for a variety of reasons," said Taylor. "Only by understanding it can we prevent it from happening again."

Taylor advised looking at the mares and the pastures for answers. She was contracted by a large stud farm in Lexington to set up a $100,000 U.S. laboratory to monitor all breeding stock in 2001 when $336 million worth of foals aborted. All scientific work to date has focused on the overwhelming presence of Eastern tent caterpillars In her study she created extensive equine blood profiles on affected mares, zeroing in on high levels of blood urea nitrogen (BUN) in all cases.

"Nitrogen is used to build protein, and the excess is then excreted from the body via the liver and kidney," she said. "When it cannot be excreted quickly enough, it will form toxic ammonia which accumulates in body fluids in such areas as the brain, eye, pericardium (the fibrous sac that surrounds the heart), and amniotic fluid, causing hypoxia (lack of oxygen) and a decrease in blood flow in tissues