Plant poisoning of livestock continues to be a widespread and economically important problem in North America. Both indigenous and imported plants can cause severe poisoning in situations where pastures or range land are overgrazed, or noxious weeds are allowed to become established.

Veterinarians are frequently confronted with the challenge of investigating the cause of sudden deaths, reproductive failure, neurological disease, photosensitization, abnormal milk flavors etc., suspected to be due to plants in the animal’s environment. This presentation will cover the important and most common causes of plant poisoning of ruminants in North America, including plant cyanogenic glycosides, nitrates, cardiac glycosides, hepatotoxic and neurotoxic alkaloids, oxalates, and plant induced reproductive failure.