By Kimberly S. Graetz
The highest number of foals/fetal samples taken to the Livestock Disease Diagnostic Center in Lexington, Ky., during the current problem with late-term abortions and early embryonic loss occurred on Derby Day, May 5, according to the Center's Director, Lenn Harrison, VMD, Dipl. ACVP. On that day, 73 foals/fetuses were brought in for examination.
Many farms have lost late-term foals during the current syndrome. However, word from a couple of veterinarians is that while early pregnancy mares might still be at risk for losing their pregnancies, the loss of these late-term foals is slowing.
Chet Blackey, DVM, a private practitioner in Central Kentucky, noted late on Tuesday, May 8, that he thinks the late gestation losses are decreasing. "My impression is that this thing is over and now we are just cleaning up," Blackey said. However, he added, "We aren't out of the woods."
Blackey's day was ending late again--as have been the days recently of many other equine practitioners in the field and clinic--after doing ultrasound exams on 125 mares. He said while it is impossible to ultrasound every pregnant mare in his practice because the breeding season is still underway and there are normal mares to get in foal, he's working in the extra ultrasound exams as he can for clients who request them.
Blackey feels that some mares with May and June foaling dates still could be compromised by the situation. On one client's farm, six consecutively foaled Thoroughbreds were compromised. Three were stillborn, three made it to the clinic, and two have survived thus far.
He added that some mares bred this year that were checked manually last week with good uterine tone, this week are losing pregnancies. "I have some farms with mares in the same field together--one was fine and another lost it (the early pregnancy). There must be some sort of individual tolerances or preferential grazing patterns." Blackey said he's heard of farms with 75% losses in the 2002 foal crop (mares bred this year), and he has one farm with no losses. But, he agreed with what Dr. Roger Murphy said at Tuesday's media briefing at the Gluck Equine Research Center--those mares losing pregnancies early in gestation are returning to cycle quickly ("Like they were never pregnant," Blackey said) and are showing no compromise in getting re-bred.
Blackey added some other good news. "I have seen no effect on stallion fertility or conception rates."
At Rood and Riddle Equine Hospital in Lexington, Bill Bernard, DVM, Dipl. ACVIM, a specialist in internal medicine, seemed to have the same feeling as Blackey as far as a slowing of stillborn foals was concerned. "It seems to have peaked and is on the downhill side," said Bernard on May 9. "We have fewer foals coming in, but that might be in part that there are fewer foals left to be born."
Bernard's recommendations for at-risk pregnant mares include giving something orally to bind the toxins, using domperidone, and keeping mares off pasture. While he said the last-named recommendation is not a good one, he has to give clients the options and let them make the decisions.
However, word from the Hagyard-Davidson-McGee veterinary hospital doesn't necessarily follow the theory that the number of late-term complications is slowing.
Doug Byars, DVM, Dipl. ACVIM, Dipl. ACVECC, head of Hagyard-Davidson-McGee's Medicine Unit in Lexington, says that while he is seeing fewer foals admitted, the hospital is full. "I took in four last night," said Byars on Wednesday, May 9. "Our impression is not that it is slowing. I think it is increasing. A lot of people are telling us they are still having stillbirths. If there are increasing stillbirths, then it's a signal that the exposure is still there or increasing."