Protecting Your Livestock from Our Region’s Toxic Plants

There are a lot of plants in the Northwest that are perfectly suitable for grazing livestock. Our tracks of land are covered in them. But, sprinkled throughout the region are toxic plants that can have disastrous effects on horses, cattle, sheep, and goats. We’ve compiled a quick list of some of the more common toxic plants with information from the Spokane County Noxious Weed Control Board, the United States Department of Agriculture (USDA), University of Missouri-Columbia Outreach & Extension, and Washington State University Extension.

Coastal Tip: If you’re unsure about a plant and its toxicity, be sure to consult your veterinarian. 

Why Animals Eat Toxic Plants

According to the USDA Agricultural Research Service, there many dozens of plants in the Western United States that are extremely toxic to livestock. The number gets a bit more manageable when you narrow it to just the Pacific Northwest. While animals will avoid the unpleasant taste of most toxic plants, the USDA warns that if an animal is extremely hungry, in need of water, stressed, or limited in its grazing opportunities, it is far more likely to eat something it shouldn’t.

Identifying Toxic Plants

The following is not a comprehensive list of toxic plants in the Pacific Northwest, but is a solid starting point in protecting your livestock from potential danger.

Arrowgrass (marshy areas)
What is Toxic: all parts of the plant, especially if the plant is dry
Possible Treatment: poisoning is quick and progressive

Black Locust (shrub)
What is Toxic: bark, leaves, and seeds are toxic
Possible Treatment: No treatment

Bracken Fern
What is Toxic: all parts of the plant
Possible Treatment: Horses or swine may be responsive to thiamin injections

Buttercups
What is Toxic: all parts of the plant
Possible Treatment: Remove plant from all pastures and grazing areas.

Deathcamus (one of the first greens of spring)
What is Toxic: all parts of the plant
Possible Treatment: Atropine and picrotoxin

Dock (also known as Sorrel)
What is Toxic: leaves and stems
Possible Treatment: veterinary care with flushing of the stomach is suggested

Elderberry
What is Toxic: all parts of the plant, especially the roots
Possible Treatment: No treatment

False Hellebore (mountain meadows)
What is Toxic: all parts of the plant
Possible Treatment: Atropine or epinephrine

Foxglove (garden flower)
What is Toxic: all parts of the plant
Possible Treatment: Atropine and limiting access to the plant

Halogeton (found on burned or overgrazed land)
What is Toxic: all parts of the plant
Possible Treatment: No treatment

Horsebrushes (on arid rangeland)
What is Toxic: all parts of the plant
Possible Treatment: Remove animal from sunlight and treat with antihistamines and steroids

Japanese Yew (shrub)
What is Toxic: Leaves, twigs and seeds are toxic.
Possible Treatment: Atropine

Jimsonweed (Thornapple)
What is Toxic: all parts of the plant
Possible Treatment: No treatment

Lambsquarter
What is Toxic: leaves and stems
Possible Treatment: Methylene blue (administered by a veterinarian)

Locoweeds (milkvetches)
What is Toxic: all parts of the plant
Possible Treatment: Remove animals from area to minimize toxicity

Milkweeds
What is Toxic: leaves, pods, seeds, and sap
Possible Treatment: No treatment

Mistletoe
What is Toxic: all parts of the plant
Possible Treatment: move livestock out of area and feed baled hay

Oak
What is Toxic: young leaves, acorn buds, and green acorns
Possible Treatment: Calcium hydroxide may help

Oleander (shrub)
What is Toxic: all parts of the plant
Possible Treatment: Atropine and propranolol

Poison Hemlock (growing in wet areas, including pastures)
What is Toxic: all parts of the plant
Possible Treatment: treat with activated charcoal and a saline cathartic, and call a veterinarian

Pigweed (found in pastures and corrals)
What is Toxic: all parts of the plant
Treatment: Methylene blue (administered by a veterinarian)

Ponderosa Pine
What is Toxic: fresh and dry needles, including young plants
Possible Treatment: Remove animals from area to minimize toxicity

Scotch Broom (grows in open meadows and along roads)
What is Toxic: all parts of the plant
Possible Treatment: treat with activated charcoal and fluids.

Sneezeweeds (elevations over 5,000 feet)
What is Toxic: all parts of the plant
Possible Treatment: Remove animals that have short exposure. Longer exposure is often fatal.

St. Johnswart
What is Toxic: all parts of the plant when fresh or dry
Possible Treatment: Removing animal from sunlight and giving steroids

Tansy Ragwort (found on rangelands)
What is Toxic: all parts of the plant
Possible Treatment: symptoms can take months to manifest. Contact a veterinarian if your livestock shows signs of lethargy, poor appetite, blindness, or liver issues.

Water Hemlock (found along streams and river banks)
What is Toxic: all parts of the plant including the roots
Possible Treatment: poisoning is quick and progressive

Wild Cherry (including choke cherry, black cherry, peach, apricot, cherry laurel)
What is Toxic: seeds and pits are poisonous
Possible Treatment: sodium nitrite and sodium thiosulfate.

Yellowstar Thistle (Russian Knapweed)
What is Toxic: all parts of the plant

Possible Treatment: No treatment and most poisonings are fatal

Get Advice at Coastal

Stop by your Northwest owned and operated Coastal today and ask about plants you think might be poisonous. Our folks know the area and can often give helpful advice and show you possible treatments for your livestock and pets. For more about toxic plants in the Pacific Northwest, read the report by Washington State University Extension titled Selected Poisonous Plants of the Pacific Northwest, which contains even more helpful advice including symptoms and images.  Additionally, a report titled Plants Poisonous to Livestock hosted on the Oregon State University website and created by the University of Missouri-Columbia Outreach & Extension has nice illustrations that can be very helpful.

Coastal Extra

If you suspect your livestock have eaten something poisonous, call your veterinarian immediately. You may be asked to identify the plants that have been ingested.

Remove your livestock from the area to ensure other animals are not poisoned as well.

Remove or eradicate noxious and poisonous plants from areas where livestock graze.