Veterinary Medicine Library

Poison Hemlock (Conium maculatum L.)

Clinical signs

Susceptible species include cattle, pigs, elk, and poultry. Toxicosis has been experimentally reproduced in sheep and horses as well.

Systemic effects:

After having eaten poison hemlock, animals may lose their appetites, salivate excessively, bloat, and have a rapid but feeble pulse. They also show evidence of muscular incoordination and appear to have great abdominal pain. Other signs include muscle tremors, frequent urination and defecation, recumbency, mydriasis, and "nervousness" followed by severe depression. In animals that die, breathing ceases due to respiratory paralysis before cardiac arrest. Convulsions, which occur in water-hemlock poisoning, do not follow the eating of poison hemlock.

Teratogenic effects:

Birth defects due to ingesting poison hemlock occur in (at least) calves and piglets and may include crooked legs (crooked calf disease, arthrogryposis), cleft palate, and kinked tails. Arthrogrypotic skeletal malformations occur in calves when poison hemlock is ingested by pregnant cows between days 40 through 70 of gestation. Similar skeletal lesions occur in pigs between days 40 through 61 of gestation. Cleft palates can occur in piglets if pregnant swine ingest poison hemlock between days 30 through 45 of gestation.

| Description & image | Distribution | Conditions of poisoning | Control | Toxic principle |

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Comments to: Greg Youngen
Updated on: 01/21/2005 VK, 03/18/1996