So, You Think You Love Horses?

Some Reflections on the Nature of Horses and Man

• Yellow Star Thistle (Centaurea solstitialis)

  [Toxic Plant to Horses] Yellow star thistle is an invasive weed found in the inter-mountain West and Pacific Northwest of the U.S. that is toxic to horses, resulting in a condition called “chewing disease” or nigropallidal encephalomalacia. Horses seem to be the only animal effected by the toxin but fortunately they must consume large amounts of it. Often animals avoid consuming toxic plants but horses find this one quite palatable.

• Yew (Taxus species)

  [Toxic Plant to Horses] Yew plants are common ornamental shrubs planted around homes but the needles are toxic to horses (also children for that manner). They contain toxic alkaloids, taxine A and B, which depress the electrical activity in heart muscle cells, producing arrhythmia. A fatal dose can be as little as 1/2 pound. If you think you have nothing to worry about I once discovered that my gardener was in the habit of throwing clippings over the fence into corners of the pasture. They had no idea that plants might be toxic to horses