Kentucky Foal Losses May Be Due To Black Cherry University of Kentucky researchers are still studying the situation that has caused 532 aborted/stillborn fetus/foal losses this year. Researchers believe cyanide, from wild black cherry trees, to be the source, with the Eastern tent caterpillars being directly or indirectly involved with Mare Reproductive Loss Syndrome (MRLS). "We want to emphasize that the current observations are preliminary, must be confirmed and that further validation is absolutely essential," University of Kentucky College of Agriculture Dean Scott Smith told a group of producers. "We haven't met reasonable standards of scientific proof. A great deal of work needs to be done. "We also wish to point out that, if confirmed, this working hypothesis would lead to a very positive outlook for prediction and prevention of recurrence of MRLS." A similar outbreak occurred in April of 1981. University of Kentucky agronomist Jimmy Henning said there is an extremely close association between the presence of the wild cherry tree, the presence of Eastern tent caterpillars in very high numbers and both early foal losses and late term abortions. This conclusion is strengthened by the findings that previous outbreaks of early foal loss were also correlated with high numbers of caterpillars. Researchers believe Eastern tent caterpillars are eating wilted black cheery leaves and then being consumed by the pregnant mares, with in six hours of eating the leaves. Wilted black cherry leaves are known to be toxic to sheep and cattle. However, researchers have now received data suggesting hemlock as possible being involved with MRLS, but they admit field observations still suggests cyanide being involved. "I think we feel confident in saying at this stage, based on several reports, that the incidence has dropped off significantly and that we can make several observations," said Dr. David Powell, Extension Professor at the University of Kentucky Gluck Equine Center. "At this stage we consider there is no need to be shipping mares out of Kentucky at this time. "Secondly, I think with the information available we can re-establish our mares on the pasture that they had been grazing." Researchers have shown white clover was not the source of cyanide. They also determined ergot alkaloids from bluegrass or orchard grass were not the cause, nor were fescue toxicosis or mycotoxins a likely cause.
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