Missouri's woodlands contain several kinds of plants poisonous to livestock. Many have a disagreeable taste that ordinarily discourages livestock. Although cattle aren't browsers, in a woodland environment they are often forced to eat plants they normally wouldn't choose. It is the leaves that cause problems for cattle. Hydrocyanic or prussic acid contained in the leaves, especially wilted ones, can be deadly.
Some herbaceous species are toxic to livestock.
The green and unripe berries and fresh leaves can poison grazing livestock. While the vegetation in woodlands can sometimes have unwanted effects on livestock, the effects of livestock on the health and productivity of a woodlot can be just as unwanted. Damage that can occur to woodlands includes damage to the trees themselves, soil compaction and erosion, and destruction of wildlife habitat. Seedling and sapling trees are the first to be hurt. These slender young trees, which are the next generation of the forest, are at just the right size and height to be eaten and destroyed by livestock.