Lawrence J. Hutchinson, Professor of Veterinary Science, Carolyn M. Burns,
Pokeweed is an unusually tall (4-5 ft.) perennial herb with purplish stems and large alternate leaves. During Spring, it has greenish white flowers. The purplish black berries resemble an elongated bunch of grapes in the fall. Pokeweed can be found in fence rows and along the edges of corn fields. Pokeweed is a poisonous plant to livestock as well as to humans. The root is the most poisonous plant to livestock as well as to humans. The root is the most poisonous part of the plant. The berries are the most attractive part of the plant, but are the least dangerous.
Pokeweed poisoning in livestock is rare because the animals generally do not eat enough of the leaves and berries to show toxic effects because these parts of the plant have a bitter taste and burns the tongue. However, pokeweed can be more of a problem during very dry conditions when other vegetation becomes more undesirable. Accidental poisoning can also occur when pokeweed is cut with corn silage and fed to the cattle green.
Symptoms of poisoning develop within one to two hours after eating. Severe diarrhea, often being bloody, is the most common sign. Other symptoms include impaired vision, shallow breathing, and lethargy. In rare cares, convulsions can occur followed by death due to respiratory failure.
Prevention is the best way to protect your herd against pokeweed poisoning. Maintain good pastures, remove all pokeweed plants from the fence rows and corn fields. Supplement forages when pastures are poor, especially during a drought. Avoid cutting pokeweed with your corn silage.