In an effort to identify a possible link to mare reproductive loss syndrome, plant scientists at the University of Kentucky College of Agriculture are investigating a number of different pasture-related theories.

"The first area we're looking at is the endophyte situation that's present in much of the old tall fescue that's present on our farms," said Jimmy Henning, UK Extension forage specialist. "We've taken samples on problematic farms for visual presence of the endophyte and have submitted samples that are being extracted and run to determine possible levels of toxicity."

Henning said although symptoms of the near full-term abortions are consistent with ingestion of endophyte-infected tall fescue by pregnant mares, many other factors must still be considered.

"One frustrating thing is that, as we have walked many pastures and looked, we've found several fields that contain very little tall fescue, so the endophyte as a potential link in many of these instances does not seem to be a good fit. Also, there is no one who really has a good handle on how much of the endophyte toxin it takes to cause this difficulty in mares."

UK plant scientists are also pursuing a number of theories, including the possibility that a new endophyte exists.

"This only a rumor, something we heard, and we're tracking it down, but it is not highly likely," said Henning. "If it's there, we're going to find it. But I don't expect it."

Henning said investigators are also exploring the possibility that there is an external fungus on the early seed heads of bluegrass that can produce a toxin, and are also looking at the possibility that certain varieties of white clover can produce cyanide during stress.

Henning's comments came during the horse farm manager's public meeting at Keeneland on Thursday evening, May 10th.