Many poisonous plants emerge in the early spring before grasses begin to grow. During cool wet springs, poisonous plants often gain an advantage over the grasses and if livestock are turned out too early, poisoning may occur. This is especially true for low larkspur, lupines, water hemlock and poison hemlock. Low larkspur is short-lived and high risk in early spring, and once seeds have shattered very little risk from low larkspur remains. Tall larkspurs are often high risk in early to mid summer when the flower/seed heads are prevalent. Storm episodes often drive cattle into areas where tall larkspur is prevalent and large cattle losses may result. Nightshades, while they emerge early, are more likely a contaminant of harvested forages than a risk for pasture-grazing animals. The toxin does not degrade in hay or silage.

These fact sheets provide information about symptoms of each plant toxicity, when and where the plants usually occur, how they affect livestock and how you can reduce loss.

Poisonous Plants Fact Sheets:

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