Re: oleanders?

Helga Loncosky (
Sun, 2 Nov 1997 17:47:24 -0500

Yes. they are very poisonous! What's worse, many horse shows landscape with
very toxic plants to horses. Have always though that was asking for
trouble! Here's a rundown on most of them!

Oleander---(Nerium oleander)-- Extremely poisonous, even humans have been
poisoned when using twigs as skewers. A single leaf is fatal to a human,
40-60 will kill a horse. Usually they won't eat this, but often it is in
trimmings, and is eaten along with everything else. Burning isn't
recommended either, the smoke can also be bad.

Bracken Fern--(Pteridium aquilinum)--Poisoning is usually in the fall, when
nothing else is left in the pasture. Whether green or dry, all parts are
poisonous. Most will not eat it, but some become accustomed to it, and will
seek it out. If it is in hay, and makes up to 20% of it or more, you will
see symptoms in a month. He must eat it from 30-60 days to see real
symptoms. It causes thyamine deficiency and central nervous system

Horsetail--(Equisetum species)--All species are poisonous, and can cause
poisoning when large amounts of it are cut in meadow hay.

Castor Bean--(Ricinus communis)--The source of castor oil is toxic. The oil
is not toxic because the toxin is not soluble in oil. The seed is
poisonous, the rest of the plant is relatively non-toxic. It should never
be around animals, as many will be curious and nibble. Even humans can be
poisoned. As little as 1/5 ounce of seeds can kill a horse. More commonly,
about 150 beans will take out a 1000# horse. Feed grains can be
contaminated with them as well. It causes severe irritation and
inflammation to the intestinal tract.

Red Maple Leaf-- Bark, wilted leaves will cause severe and rapid hemolytic
anemia. Signs come 3-4 days afterward.

Yellow Star Thistle--(Centaurea solstitialis) and Russian
Knapweed--(closely related species)--They are distantly related to the
sunflower family. It takes 30-60 to show up, but it hits instantly. When
the horse can't eat and is unable to also drink, call a vet ASAP. Caught
early, and aggressively treated, they may live.

Lupine--There are many species that are non-toxic, but it is very
difficult to tell them apart from the very toxic ones. The toxic lupine is
poisonous at all stages, but worst as young plants and at seed stage. Once
again, if there are quantities in hay, the poisoning can be slow. Will kick
the liver, and cause gastrointestinal problems.

Locoweed--(Astraglus & Oxytropis)--There are 300 hundred species, only
about 20 are poisonous. AS with lupine, even a botanist would have a hard
time telling the good from the bad. They are poisonous at all stages, at
all times of the year, even after being cut and dried. All parts are toxic.
Once again, signs come in at around 6 weeks.

Timber Milk Vetch--(Astraglus)--Poisoning comes quickly in 2-7 days, and it
causes a roaring sound, which is advent to death from affixiation.

Some plants that cause selenium poisoning are--

Prince's Plume-(Stanleya)
Woody Aster--(Xylorrhiza)
Golden Weeds--(Oonopsis)

Nicotine -- (Solanaceae)--Potato family plants are potentially poisonous,
as well as wild tobaccos--(Nicotiana).

Cirrhosis of the Liver can be caused by the following plants--

Fiddleneck, Tarweed, Fireweed, Yellow Burr Weed, Buckthorn--(Amsinckia)

Ragwort, Groundsel, Stinking Willie--(Senecio), (Senecio jacobaea)

Rattle Weed, Rattle Box, Wild Pea--(Crotalaria spectabilis),(Crotalaria
sagittalis)--Related to the pea family.

Ground Ivy--(Glechoma hederaceae)--Always a problem no matter what stage,
even dried and cured.

Poison Hemlock--(Cituta)--All parts are poisonous, especially from spring
to time it flowers. Horrible for horses, humans, cows, and sheep. 4-5 #
fresh leaves have killed horses. Signs occur within hours of ingestion.

Western Water Hemlock--Sometimes confused with poison hemlock, it is the
most poisonous plant growing in the US. It may also be called poison
parsnip,snakeroot,false parsley,. Tiny amount of the toxic alcohol is
needed to poison. It is wetland plant. Horses show signs within 15 minutes
to 6 hours, and usually die within an hour of shown symptoms.

Forage Poisoning--Caused by damaged corn and moldy corn. Acts like sleeping

Larkspur--(Delphinium)--Garden delphiniums are just as bad. 2nd only to
locoweed in livestock death.

Marijuana--(Cannabis)--Death occurs within 15-30 minutes of ingestion. Hemp
does grow wild, so beware.

Sorghum & Sudan Grass Toxicity-- Show 2 clear kinds of poisoning, prussic
acid (cyanide), and the infection of the urinary bladder that travels up to
the kidneys. It is not seen with hay made from these plants, but beware of
it in pasture. Johnson Weed has also done this.

Bermuda Grass Tremors--Ergot is a fungus that grows in certain grasses,
such as this. It is also seen on rye and dallis grass. More common in late
summer, fall, and winter.

Chokecherry--(Prunus)--The leaves cause cyanide poisoning, and are more
toxic when wilted, dry, frozen, etc. Death can occur within minutes to
hours after ingestion.

Other Misc. Poisonous Plants--

Common garden flowers like Iris, Foxglove.
Black Locust-bark and all.
Acorns/Oak Leaves
Wild Jasmine
Overripe Crimson Clover
Death Camas
Large Quantities of Apples, Chives, Onions, Wild Onions can cause toxicity
and colic.

Mechanical Injurious Plants--
Longbearded grasses, Barley, Foxtail, Cheat grass(Bromus tectorum), Yellow
Bristle grass(Setaria glauca, S. lutescens). These all can/will cause
ulcers and sores within the mouth and throat.

There are more, but this is the main list. If you have any questions
regarding them, symptoms, cures/treatments, etc, feel free to ask. Hope you
find this info helpful!

Helga Loncosky
Beacon Morgan Horses
"There is something about the outside of a horse
that is good for the inside of a man."
-----------Winston Churchill

> From: Susan Evans Garlinghouse <>
> To:
> Subject: oleanders?
> Date: Saturday, November 01, 1997 8:04 PM
> Hi all,
> Could one of the vets (or anyone else) on the list tell me whether
> oleander is really as toxic to horses as they say? I've heard
> everything from "it doesn't matter because no horse will eat it" (yeah,
> right) to "one leaf and they're dead within 24 hours". I heard stories
> a few years ago about Friesians being fed a handful of oleanders by
> well-intentioned show-goers and dying soon thereafter despite veterinary
> intervention.
> The reason I ask is because an Elks Lodge is being built right next to
> my place and they want to be able to plant oleanders on the greenbelt
> that separates their property from my horse's corral. Despite a planned
> six foot barrier wall, I know how high oleander can grow and believe me
> when I say that there is no force in nature that will keep George of the
> Jungle (the former Spudnuts, 'cept now we're Spudnutless :-D) out of any
> trouble he sets his sights and appetite on. Not to mention leaves drop
> and winds blow and s**t happens. The final Planning Commission hearing
> is next week and I plan to be there raising holy hell about oleanders if
> this is a threat to my horses. When I called the Elks themselves, I got
> blank looks and a response of, "Oh, don't worry, we have plenty of
> insurance to cover that sort of liability." Like I could place a value
> on Dakota, Cato, Katy and Puzzle. Argh.
> Sorry, I know this isn't directly endurance-related, except that if I'm
> right and they're wrong, there might be four less endurance horses in
> the world...any help would be appreciated. Thanks!
> Susan and...
> Cato ("you know I never eat anything that moves in the wind")
> Katy ("you know I never eat anything not directly from Daddy's hands")
> Puzzle ("you know I never eat anything except sand and leg wraps")
> Dakota aka George of the Jungle ("Look! They're putting in a salad bar
> next door!")