RESOURCES FOR
INFORMATION on PLANTS AND FLOWERS THAT ARE TOXIC TO HORSES
Generally, in the US, each
state has some info available about poisonous plants in their state/region via the state universities that are oriented to
vet training. Certain private universities will offer information too.
Canada has a Ministry
office that has a list and resources for particular provinces.
The following is a limited reference list for resources. Feel
free to send a link if you know of a particularly useful one. Canada links
provided too.*
CALIFORNIA
University
of California at Davis
http://wric.ucdavis.edu/information/poisonous.pdf General information on US poisonous plants, listed by type of injury (mechanical,
digestive, etc). Pdf download.
http://envhort.ucdavis.edu/ce/king/PoisPlant/Tox-COM.htm General list of poisonous plants that includes Toxicity class and what to do if exposed to such. Includes California emergency phone contacts.
CANADA
http://www.gov.on.ca/OMAFRA/english/livestock/horses/facts/poison.htm Ontario, Canada's Ministry of Agriculture and Food; list of plants, pictures, symptoms of poisoning, emergency
phone contacts.
Noteable common plants: buttercups, yews, oleander, field horsetail, some ferns.
http://www.cbif.gc.ca/pls/pp/poison?p_x=px
Canadian government Poisonous
Plant Information System
COLORADO
Colorado State University
http://www.vth.colostate.edu/poisonous_plants/report/search.cfm
Large general database;
enter “horse” in the search box—comes up with 82 common and botanical names of plants and flowers with pictures,
link to further information. The info includes how to diagnose, treatment and
symptoms of poisoning, and a map showing the primary areas that are affected. Includes
more scientifically technical information.
INDEPENDENT RESEARCH ON
LAMINITIS (FOUNDER)
Kathryn Watts has a website
on primarily grass founder. Offers research and consulting services nationwide.
www.safergrass.org
FLORIDA
www.floridahorse.com
Just provides a list, no
further information
List includes: African violets,
dieffenbach, philodendron, impatiens, yew evergreens, angels trumpet
INDIANA
Purdue
University
http://www.vet.purdue.edu/depts/addl/toxic/byanim.htm
Direct listing of common
names of plants and link to info for horses, all animals, pets. Info includes
pictures, causes, symptoms, immediate action to take, contact phone numbers.
Noteable common plants:
oats with lots of nitrate, st.johnswort, johnsongrass, fescue, lupine.
NEW
YORK
Cornell
University
TOXIC PLANT DATABASE FOR HORSES
http://www.ansci.cornell.edu/plants/horselist.html
NORTH
DAKOTA
North Dakota University
http://www.ext.nodak.edu/extpubs/plantsci/hay/r1062w.htm
OHIO
http://ohioline.osu.edu/b762/b762_24.html
Ohio State University online--covers mostly Ohio, however includes extensive info on plants that may be found many places,
including poison and symptoms.
OKLAHOMA
http://www.noble.org/Ag/Forage/HorseForage/page16.html#Definite
The Noble Foundation in Ardmore, Oklahoma offers an excellent site for any and all information on horse pastures in the
Southwest region in particular—from start to finish under the heading “Horse Forage and Forage Management”.
The above link is direct to the poisonous plant list. Left hand side
for other links within the directory. The Plant Image directory has very specific
and complete photos of many plants, flower, grasses and shrubs and trees useful in identification, as well as with information.
OREGON
Oregon
State University
http://extension.oregonstate.edu/linn/content1/poisonplants.php
Includes color pictures
and direct link to info.
Noteable plants and flowers
include: larkspur, red maple
TEXAS
Texas
A&M
College
Station, Tx.
http://aggie-horticulture.tamu.edu/plantanswers/publications/poison/poison.html List of house and outside plants by terrain that are poisonous. Handy
one page list.
http://www.tamu.edu/univrel/aggiedaily/news/stories/01/031201-3.html Concise article on plant poisoning in horses and plants that cause them.
http://nueces-tx.tamu.edu/AG/Livestoc/PASTURE/Toxicpla.pdf Toxic plant management booklet for the Texas-Pecos region—pdf download.
US GOVERNMENT
http://plants.usda.gov/cgi_bin/link_categories.cgi?category=linkpoison
US Department of Agriculture
list of links to information on toxic plants and flowers. This includes plants
that are toxic to humans.
Poisonous and Medicinal Plants Links
WISCONSIN
University of Wisconsin
http://ipcm.wisc.edu/uw_weeds/extension/articles/poisonpasture.htm
Excellent article
that includes a list of poisonous pasture weeds and discussion of recent research findings; with references cited. Early
90's publishing date.
http://www.burnettcounty.com/rurallivingguide/outdoorhazardsinWI.pdf
A general guide to
Toxic insects, plants and wildlife in Wisconsin. Pdf download.
EQUINE WEB SITES WITH INFORMATION
http://horsecare.stablemade.com/articles2/poisonous_plants_3.htm
Some
Ornamental Plants, Shrubs and Trees Potentially Poisonous for Horses and Common Plants
www.safergrass.org
Lots of free information
on laminitis (founder)
GENERAL INFORMATION
ON HORSE POISONING
Horse
Poisoning from Oregon State
University
. 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
PLANT TOXICITY in HORSES
FROM the Canadian Ministry
Horses will usually avoid eating poisonous plants (they don't taste
very good) as long as there is an abundant supply of good quality hay or pasture available. However, faced with no pasture
or hay, a horse might decide to sample one of the poisonous weeds still left standing in the field.
The best medicine for dealing with poisonous plants is ... PREVENTION.
- Ensure that horses on pasture have adequate hay
and/or pasture so that they won't have to resort to eating poisonous weeds.
- Avoid overgrazing, if no supplemental hay is
provided.
- Learn to recognize poisonous weeds and control
them by pulling or by use of commercially registered herbicides.
- Examine your hay for unwanted plants.
Did you know?
Carbohydrate levels in grass
can increase the chances of your horses foundering.
(www.safergrass.com)
Black walnuts can cause
founder (stablemade link)
A single ounce of oleander
leaves can kill a 1000 pound horse—it has an effect similar to digitalis in human on the heart. (Several databases
including Purdue).
Needles from yews whether
dead or alive can cause immediate sudden death. Yews are often used in containers,
so avoid for decoration of rings, etc. (several databases, including Purdue)
Johnson grass contains cyanide
in leaves and stems. (Purdue)
Toxic levels of nitrates can accumulate in
Johnsongrass following heavy fertilization or drought and result in toxicosis which be confused with cyanide poisoning
(Ohio State info)
Two safe plants are crepe myrtle and red photip. (Texas A&M)
Many species of cherry
and peach trees are poisonous--once eaten, they produce cyanide poisoning in the digestive tract. Does seem to affect
ruminant animals more than horses, however, it does result in death within an hour. Includes eating of wilted leaves.
(Ohio State)
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*L.Robinson
is not responsible for any of the accuracy of any of the information provided.
