Poisonous plants are a major cause of economic loss to the livestock industry. Two poisonous plants common to Oregon are poison hemlock and Western water hemlock. Ingestion of either by humans or livestock typically results in death.
Silage-making has been used to reduce the concentrations of toxins in a variety of crops. But in the case of poison hemlock, the opposite is true — making silage out of it actually increases one of its toxic alkaloids.