Plants Poisonous to Livestock and Horses

Click on an image below to see more details about that weed

Creeping Buttercup	Field Horsetail	Jimsonweed	Mayweed/Dog Fennel	Hairy Vetch
Curly Dock	Dutchman's Breeches	Foxtail Barley	St. Johnswort	Foxglove
Yellow Starthistle	Hairy Nightshade	Wild Iris	Redroot Pigweed	Tall Larkspur
Poison Hemlock	Medusahead	Death Camas	Tansy Ragwort	Lambsquarters
Coast Fiddleneck	Large Leaf Lupine	Spotted Catsear/False Dandelion	Western Brackenfern	Rhododendron
Yew	*Sorghum Family	*False-Hellebore	Cocklebur	*Castor Bean
White Oak	Black Walnut	Red Maple	Cherry/Stonefruits	Western Water Hemlock

* Image from the Cornell Poisonous Plants Web Page system http://www.ansci.cornell.edu/plants/comrest.htmlAll other photos are courtesy of Oregon State University.Comments:
1. Poisonings are most likely to occur with very young animals or animals newly brought into the area.
2. Generally, livestock do not graze toxic plants in a pasture as long as there is abundant, palatable feed. (Tall larkspur and lambsquarters are exceptions.)
3. Examine pastures in August. Weedy species left untouched are either toxic, unpalatable or thorny.
4. Most poisonings occur in hay, so check hay closely for weeds. Starthistle can be a hay contaminant from southern or eastern Oregon.
5. Foxtail Barley and Medusahead cause mechanical injuries.
6. Lambsquarters and Amaranth are nitrogen accumulators.
7. The corn family foliage, when frosted or drought stressed, is toxic to horses.
8. Blister beetles are very toxic to horses and are sometimes found in hay. There are many kinds of blister beetles that feed on hay and pasture crops.
9. Camelids have other toxin problems.There are many poisonous plants that may be toxic to livestock and horses that are not referenced on this list.

Do not assume a plant is not toxic just because it is not listed here.This material is provided as information only and is not to be used for the home treatment of animals.

Please contact your veterinarian or poison control if poisoning is suspected.

For further information, the Cornell University website contains many links to information on poisonous plants, http://www.ansci.cornell.edu/plants/comrest.html

Authors: Ross Penhallegon, Pat Patterson, Larry Campbell, Pete Schreder
OSU/Lane County Extension Service
Revised March 2002

last updated July 16, 2003