A herd of Thoroughbred mares in Kentucky presented with unexplained signs of weight loss and emaciation despite supplemental hay and grain. The mares were grazing in a pasture with an abundance of buttercup plants. All the horses, especially lactating mares and their foals, demonstrated mild to severe weight loss. Seven of the mares were confirmed pregnant between days 30 and 45 days of pregnancy. These seven mares were later found to have aborted. Two 2 year old fillies developed diarrhea, incoordination, recumbancy, paralysis and were later humanely euthanized.
The Kentucky Equine Research Center states “This bitter-tasting oil irritates the lining of the horse’s mouth and digestive tract. Owners may notice blisters on the horse’s lips, swelling of facial tissue, excessive salivation, mild colic, and diarrhea that might contain blood. Decreased appetite and a slowed pulse may also be present. In severe cases, buttercup ingestion can lead to skin twitching, paralysis, convulsions, and death. Affected horses can display hemorrhaging and congestion in the lungs on postmortem examination. Cattle, goats, and pigs are also susceptible to the toxin” (p.1).
The horses were moved to pastures without buttercups on another farm and recovered uneventfully. Mares that had lost their pregnancies successfully conceived the following year.
All classes of livestock are susceptible. The clinical signs associated with ingestion of buttercups may appear similar to other gastrointestinal and/or neurological syndromes. This presentation demonstrates the significance of an on-farm investigation of feed and pastures.
Kentucky Equine Research. Buttercup Toxicity. August 7, 2013 retrieved from http://www.equinews.com/article/buttercup-toxicity-horses
Swerczek, T.W. (2016). Abortions in Thoroughbred mares associated with consumption of bulbosus buttercups (Ranunculus bulbosus L). JAVMA 248(6) p 669-672. doi: 10.2460/javma.248.6.669
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