An outbreak of early-term fetal loss in 1980 was eventually discounted by researchers as an "artifact epidemic" caused by earlier than usual examinations. Still, that outbreak now is viewed by many as similar in nature to the current syndrome that many Central Kentucky farms are experiencing. According to experts such as Dr. David Powell of the University of Kentucky Gluck Equine Research Center, the current problem is much more widespread than in 1980.
The 1980 outbreak occurred in late May and early June, weeks after a frost was reported to have hit the region on a particularly cool May 9 night. After concern was expressed by Central Kentucky breeders and veterinarians, Dr. Joe Hendricks, an epidemiologist with the United States Department of Agriculture was hired by the Kentucky Equine Practitioners to conduct a study.
For the purposes of the study, the term abortion was "limited to those mares diagnosed 60 days or more in foal and later found barren." Further, Dr. Hendricks limited his figures to farms reporting "multiple cases" of abortion. According to a report in The Blood-Horse
, a total of eight farms submitting data fit these conditions. Hendricks found from those eight farms: "There were 127 mares in approximately the same stage of pregnancy located in 10 pastures on eight different farms. Fifty-one or 40.16% of these aborted." Of the 51 mares that aborted, 26 were maiden mares, 14 were barren mares, and 11 were foaling mares. They were covered by 40 stallions located at 14 different stud farms.
Hendrick wrote: "Since a specific pathogen has not been recovered from most of the cases, consideration should be given to the possibility that the cause is of a toxic nature."
Citing limited data available, Hendrick was unable to draw any substantive conclusions. In his report to the Kentucky Equine Practitioners, he said 1) there was no evidence of venereal transmission of disease; 2) the data did not show the cause to be a communicable disease; 3) the incidence of abortion decreased with time; 4) the more severely affected farms are widely distributed in the Central Kentucky region.
Later in the year, Dr. John T. Bryans of the University of Kentucky concluded that the believed increase in abortions was the result of changes in procedures for checking mares for pregnancy and termed the affair an "artifact epidemic."
"The apparent 'outbreak' seems to have been precipitated by examinations of mares that would not have been done until September in most routine veterinary practices," Bryan said. "There weren't more mares coming up empty than usual, we were just discovering them earlier. There were a couple of unusual occurrences. One veterinarian found five mares out of five in one field, and there was nothing in common at all among those five. Maybe those just happened to be the five he was going to lose anyway. And another veterinarians lost 15 on his place.
"The vast majority of our veterinarians did not have anything unusual going on. There is not a new disease. I can tell you that."
That was 1980. In May of 2001, with farms throughout the region hurriedly ordering ultrasound scans to check on the status of their in-foal mares, researchers are scrambling for answers.