Warning: Yews are extremely toxic to livestock
Earlier this season in St. Joseph County, a farmer found out the hard way that yews (Taxus
spp.) are extremely toxic to cattle. A few overgrown bushes were
removed from a landscape one afternoon and pulled into a pasture area.
The intention was to burn them once all were removed and dried. The next
morning, all 10 cattle in the pasture were dead. Plant material
submitted to the lab was identified as Japanese yew (Taxus cuspidata).
Taxus is the genus that includes numerous forms of evergreen shrubs or trees used in the landscape. Common species include Canada yew (T. canadensis), English yew (T. baccata), Japanese yew (T. cuspidata) and Anglojap yew (Taxus x media). Cultivars of the Anglojap yew, a cross between T. cuspidata and T. baccata, are some of the most encountered at garden stores.
Yews have linear, sharp-pointed, approximately one-inch long, needle-like leaves that are dark green above and yellow green below. Leaves are spirally arranged but generally lie flat on the stem. Flowers are inconspicuous with mildly attractive, red, berry-like fruit.
All parts of yews, except the red, fleshy part around the seed, are extremely toxic to cattle and other livestock. The primary toxin is taxine, which is a mixture of alkaloids that act upon the heart and usually result in death of the animal. Uprooted bushes and clippings should never be placed near livestock. Yew is generally not highly palatable to livestock. However, animals are more likely to graze on tender new growth or clippings discarded in a pasture. As little as a mouthful to 1 lb. of yew clippings is sufficient to kill a 1000 lb. animal in only a few minutes.