EKAHA
Identification Guide:Toxic Plants
Compiled By:Charlie Armour
Poisonous Plants
Black Locust (Robinia pseudoacacia 1
Bracken Fern (Pteridiu m aquliinium) 2
Buckwheat (Fagopyrum esculentum) 2
Castor Bean (Ricinus communis) 3
Cherries(Wild):Black Cherry, Bitter Cherry, Choke Cherry, Pin Cherry
(Prunus) 4
Clover (Trifolium spp.) 5
Sweet Clover (Melilotus alba spp.) 6
Fiddleneck (Amsinckia intermedia) 7
Groundsels, Senecio, and Ragworts (Senecio spp.) 8
Horsetail (Equisetum arvense spp.) 9
Jimsonweed (Datura stromonium) 9
Locoweed (Astragalus and Oxytropis spp.) 10
Climbing Nightshade, Black Nightshade, Potato (Solanum spp.) 11
Oaks (Quercus spp.) Red Oak, White Oak, and Black Oak 11
Red Maple (Acer rubrum) 12
Rhubarb (Rheum rhaponticum) 13
Russian Knapweed, Yellow-Star Thistle 13
St. John's Wort (Hypericum perforatum) 14
Sensitive Fern (Onoclea sensibis) 15
Sorghum or Milo, Sudan Grass, and Johnson Grass ((sorghum spp. 16
Yew (Taxus spp.)52
Schrubs, Flowers and Trees Known to be Safe 17
Toxic Plants
Toxic Plants can be found in most, if not all, pastures. It should
be our responsibility as horse owners to be able to identify the
plants that may harm our horses and also the symptoms related to
each. Early recognition of the symptoms can mean the difference in
saving your horses life.
There is good news, too. These plants are rarely the horses' first
choice as forage. Due to the bitter taste and generally unpalatable
textures, horses rarely ingest these plants. However, even the best
pastures may harbor these potential killers and horses may
inadvertently eat them, so be prepared.
NOTE: While many of these plants have no treatments listed in the
literature, if you suspect poisoning of your horse, you should
immediately call your veterinarian for definitive diagnosis and
possible treatment.
Schrubs, Flowers and Trees Known to be Safe 17
Toxic Plants
Toxic Plants can be found in most, if not all, pastures. It should
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be our responsibility as horse owners to be able to identify the
plants that may harm our horses and also the symptoms related to
each. Early recognition of the symptoms can mean the difference in
saving your horses life.
There is good news, too. These plants are rarely the horses' first
choice as forage. Due to the bitter taste and generally unpalatable
textures, horses rarely ingest these plants. However, even the best
pastures may harbor these potential killers and horses may
inadvertently eat them, so be prepared.
NOTE: While many of these plants have no treatments listed in the
literature, if you suspect poisoning of your horse, you should
immediately call your veterinarian for definitive diagnosis and
possible treatment.
Black Locust (Robinia pseudoacacia)
The seeds, bark, and leaves contain toxic proteins that have caused
sickness and death in horses. The plant should be considered toxic
to all animals if eaten. This tree can be found around older farms
and houses and is also planted along fence rows. If older trees are
cut down in areas where horses have access, make sure they do not eat
any sprout (sucker) growth that may emerge from the stump.
Nomenclature
Botanical name Robinia pseudoacacia
English Common name: Black Locust
Botanical family name: Leguminosae
English family name: pea
Toxic parts: bark, leaves, seeds
Toxic chemicals: Robin (or robinin) and phasin, which are toxic
proteins called toxalbumins, are present in black locust. A
glycoprotein that clumps red blood cells has been extracted from the
plant. It is not clear if this is robin or another substance.
Experimental feeding to horses has shown the following toxicity:
=> aqueous extract of bark about 0.1% of body weight caused symptoms
=> powdered bark about 0.04% of body weight caused symptoms
General symptoms of poisoning: Horses that have eaten black locust
leaves, sprouts, and bark were poisoned and died. Symptoms include
loss of appetite (anorexia), weakness, paralysis of the hindquarters,
nausea and coldness of the extremities. Symptoms of colic also occur.
In severe cases, death may occur.
Bracken Fern (Pteridiu m aquilinium)
Bracken is a native fern. Horses have been poisoned after eating
bracken. Bracken contains several chemicals that cause problems.
Thiaminase results in vitamin B1 deficiency in nonruminants such as
horses. Ptaquiloside, a carcinogen-mutagen, causes acute and chronic
symptoms of illness in ruminants (cows). The spores may contain
carcinogens that can cause problems to animals as well. The young
fronds of bracken contain significant quantities of the carcinogen.
Nomenclature
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Botanical name Pteridium aquilinium
English Common name: bracken
Botanical family name: Polypodiaceae
English family name: fern
Toxic parts: all parts including leaves, rhizomes, spores and young
shoots
Toxic chemicals: thiaminase, ptaquiloside, prunasin and aqualide A
General symptoms of poisoning: Symptoms can include loss of appetite,
convulsions, colic, coffee-colored urine, lack of oxygen in the blood
(cyanosis - characterized bya bluish or purplish discoloration of the
skin or mucous membranes), stiff gait, a tendency to lay down, low
red blood cell count (anemia), and death.
Buckwheat (Fagopyrum esculentum)
Buckwheat is cultivated as a crop for fodder and for the production
of buckwheat honey. Eating entire plants, dried or fresh, has caused
sensitivity to light in horses with exposed light-colored skin.
Exposure to the sun is necessary. This plant is considered to be a
primary photosensitizer, although jaundice has occurred at the same
time, which indicates secondary involvement of the liver. Exposure
may cause various allergic and non-allergic reactions including
asthma, skin disorders, fever reactions, and airway obstruction and
inflammation.
Nomenclature
Botanical name: Fagopyrum esculentum
English Common name: buckwheat
Botanical family name: Polygonaceae
English family name: buckwheat
Toxic parts: all parts
Toxic chemicals: Fagopyrin, probably a derivative of
naphthodianthrone, is closely related to hypericin, which is found in
St. John's-wort. The absorption spectra of these chemicals is in the
range of 540-610 nm
General symptoms of poisoning: loss of appetite, staggering gait,
peeling of the skin and thirst.
Castor Bean (Ricinus communis)
The seeds from the castor bean plant are poisonous to people,
animals and insects. One of the main toxins is ricin. Also present
is RCA (Ricinus communis agglutinin). Ricin is a potent cytotoxin but
a weak hemagglutinin, whereas RCA is a weak cytotoxin and a powerful
hemagglutinin. Poisoning by eating of the castor bean is due to
ricin, not RCA, because RCA does not penetrate the intestinal wall,
and does not affect red blood cells unless given intravenously. If
RCA is injected into the blood, it will cause red blood cells to
burst. Castor beans are used as an ingredient in some animal feeds
after the oil has been extracted or inactivated by heating for 20
minutes at 140oC. Attempts to use castor beans in feed for horses
involve different methods of inactivating ricin while maintaining
nutritional value. Some studies have shown that even after such heat
treatment toxicity remains. Poisoning of livestock usually occurs by
accidental incorporation of castor beans in their feed. Horses are
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particularly vulnerable.
Nomenclature
Botanical name Ricinus communis
English Common name: castor bean
Botanical family name: Euphorbiaceae
English family name: spurge
Toxic parts: seeds
Toxic chemicals: Ricin, RCA (Ricinus communis agglutinin)
General symptoms of poisoning: The accidental addition of castor
beans into grain given to horses can cause sweating, rocking gait,
rapid pulse, muscle spasms, high temperature, and abdominal pain. The
early symptoms may be confused with respiratory infection.
Cherries (Wild):
Black Cherry, Bitter Cherry, Choke Cherry, and Pin Cherry (Prunus)
Chokecherry is a native plant that appears as a shrub or small tree.
Horses have been poisoned and have died after eating large quantities
of berries, which contain the seeds. Eating the plant material can
poison all types of livestock. (Related species, including peach
(Prunus persica) and apricot (Prunus armeniaca), have pits with
enough toxin to cause poisoning and death in humans and animals. Pin
cherry (Prunus pensylvanica) is a native tree that can be found
throughout most of the US. The leaves have an average nitrogen rate
of 91 mg/100 g, with as much as 143 mg/100 g recorded. These levels
are potentially lethal to horses if eaten. At all stages of growth,
leaves of red chokecherry contain quantities of prunasin that are
well above the minimum 1.4% level required for acute poisoning. Twigs
also contain levels of prunasin at or above the level required to
cause acute poisoning. Twigs developed more toxin during dry years.
The prunasin level of buds and flowers is above the minimum level as
well.
Nomenclature
Botanical name: Prunus Virginiana L., Prunus pensylvanica L. f,
Prunus serotina
English Common name: red Chokecherry, Pin cherry, Black Cherry
Botanical family name: Rosaceae
English family name: rose
Toxic parts: leaves, berries, pits, twigs, buds, flowers
Toxic chemicals: amygdalin, prunasin.
General symptoms of poisoning: Eating as little as .25% of body
weight of plant material can lead to coma, convulsions, lack of
oxygen in blood, and death by asphysiation. Additionally, you may see
staggering gait or extreme agitation. Drawn blood is usually bright
red. Onset of symptoms is often sudden and acute.
Clover (Trifolium, spp.)
Cases of sensitivity to light have occurred from eating this feed
plant, sometimes accompanied by liver enlargement and damage. All
toxic compounds have not been identified, although nitrate poisoning
is one likely suspect. Eating red and white clover plants can cause
bloat, infertility and conditions known as 'congenital joint laxity'
and 'dwarfism' in foals. White clover has caused laminitis in horses.
After the plants are eaten, some varieties can liberate HCN, causing
cyanogenic poisoning in animals. White clover is also reported to
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cause birth defects if infected with various fungi.
Nomenclature
Botanical name: Trifolium spp.
English Common name: clover (alsike, red, white)
Botanical family name: Leguminosae
English family name: pea
Toxic parts: All parts
Toxic chemicals: nitrate, isoflavones, Two cyanogenic glycosides,
linamarin and lotaustralin, are found in white clover. In young
leaves, the cyanogen levels may reach 350 mg of HCN per 100 g of
tissue. Two independently inherited genes in white clover control
cyanogenesis. Only plants possessing at least one dominant functional
allele of both genes liberate HCN when damaged.
General symptoms of poisoning: depression, staggering gait,
blindness, liver disease (cirrhosis), severe degeneration of the
kidneys, infertility, laminitis (tenderness, swelling, and
inflammation around the hooves).
Sweet Clover (Melilotus alba spp.)
White sweet-clover is a cultivated and naturalized plant that occurs
as a weed. This plant contains a glycoside with a coumarin fraction.
When sweet-clover is harvested for feed, the succulent stems usually
mold before drying. The molds metabolize the glycoside into
dicoumarol, which interrupts vitamin K activation of prothrombin,
necessary in blood clotting. Levels of dicoumarol at more than 10 ppm
are suspected of possible poisoning. Dicoumarol levels are usually
higher in small and round bales than in stacks.
Nomenclature
Botanical name Melilotus Alba Desr.,
English Common name: White Sweet Clover, Yellow Sweet Clover
Botanical family name: Leguminosae
English family name: pea
Toxic parts: leaves and stems. Moldy sweet-clover is produced through
insufficient drying of bales and silage. Dicoumarol production by
molds is not likely to occur if animals ingest living plants.
Toxic chemicals: dicoumarol, melilotoside
General symptoms of poisoning: Eating moldy sweet clover forage can
lead to low red blood cell count, swelling and hemorrhage. Treatment
is possible with whole blood transfusion and injections of 4.2 g of
menadione sodium bisulphate. Vitamin K1 is also effective in
treatment.
Fiddleneck (Amsinckia intermedia)
An introduced plant found mainly in California and the Pacific
Northwest. Eating fiddleneck can cause severe diseases in horses.
Liver damage results from eating the seeds of the plant. The symptoms
are known as 'walking disease' in horses.
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Nomenclature
Botanical name: Amsinckia intermedia
English Common name: fiddleneck
Botanical family name: Boraginaceae
English family name: borage
Toxic parts: seeds
Toxic chemicals: intermedine, lycopsamine, echiumine, The
pyrrolizidine alkaloids of fiddleneck cause liver damage in horses,
mainly a result of the presence of the seeds in grain and grain
screenings fed to livestock.
General symptoms of poisoning: The presence of blood in the urine,
continous aimless walking, extreme nervousness, liver damage, death.
Groundsels, Senecio, and Ragworts (Senecio spp.)
Entire-leaved groundsel (Senecio integerrimus) is a native herb. This
plant has caused poisoning of horses. Eating the plant material over
long periods causes irreversible liver damage. This plant grows when
other forage is abundant so that it is not a toxic threat unless
forage is scarce or the plant is abundant in an area to be cut for
hay. Tansy ragwort contains pyrrolizidine alkaloids that primarily
cause irreversible liver damage. Tansy ragwort should be eradicated
from forage and crops. Animals may be poisoned if they drink the milk
of other animals that have eaten this plant, i.e., foals. Horses may
stagger, press their head against objects, and walk in a straight
line regardless of obstructions.
Nomenclature
Botanical name Senecio integerrimus,Senecio jacobaea, Senecio vulgaris
English Common name: entire-leaved groundsel, tansy ragwort, common
groundsel
Botanical family name: Compositae
English family name: Composite
Toxic parts: All parts
Toxic chemicals: Toxic agent unknown in groundsels. Pyrrolizidine
alkaloids are found in other toxic members of the genus Senecio and
are probably the chemicals responsible for cases of poisoning found
in experiments. Pyrrolizidine alkaloids such as jacobine and
seneciphylline are found in tansy ragwort. The content of these
alkaloids has been measured at a mean level of 0.31%.
General symptoms of poisoning: confusion, restlessness, weakness,
depression, abdominal swelling, peeling of skin, weight loss, coma,
yellowish discoloration of the skin and mucous membranes (jaundice)
and liver damage leading to death. Eating plant material causes
jaundice, a sweet odor from the skin and, after 1 or 2 days,
insensibility to objects and pushing against obstacles, urine
discoloration, and death. All horses that showed definite symptoms
died. Liver damage was apparent upon postmortem examination.
Horsetail (Equisetum arvense spp.)
Field horsetail is a native plant. This plant contains thiaminase,
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which causes thiamine deficiency in horses. Eating the leaves and
stems of field horsetail has poisoned horses.
Nomenclature
Botanical name Equisetum arvense
English Common name: field horsetail
Botanical family name: Equisetaceae
English family name: horsetail
Toxic parts: leaves and stems
Toxic chemicals: Thiaminase is an enzyme that splits thiamine, a B
vitamin, making it inactive. Thiamine is involved in decarboxylation
reactions in animal bodies. Deficiency of thiamine leads to
accumulation of pyruvate in the blood, with a resulting impairment in
energy metabolism and cellular shortage of ATP. Hay that contains
horsetail at a level of 20% or more may produce symptoms of thiamine
deficiency in horses in 2-5 weeks.
General symptoms of poisoning: Symptoms can include loss of
appetite, inability to coordinate voluntary muscle movement (ataxia),
colic, stiff gait, a tendency to lay down and low red blood cell
count. Severe cases can lead to convulsions and death.
Jimsonweed (Datura stromonium)
Poisoning can occur when hungry animals are on sparse pasture with
Jimsonweed infestation. Most animal poisoning results from feed
contamination. Jimsonweed can be harvested with hay or silage, and
subsequently poisoning occurs upon feeding the forage.
Nomenclature
Botanical name Datura stromonium
English Common name: Jimsonweed
Botanical family name:
English family name: Jimsonweed
Toxic parts: All parts of Jimsonweed are poisonous. Leaves and seeds
are the usual source of poisoning, but are rarely eaten do to its
strong odor and unpleasant taste.
Toxic chemicals: Jimsonweed toxicity is caused by tropane alkaloids.
The total alkaloid content in the plant can be as high as 0.7%. The
toxic chemicals are atropine, hyoscine (also called scopolamine), and
hyoscyamine.
General symptoms of poisoning:.
Early Signs
rapid pulse restlessness frequent urination
rapid breathing nervousness diarrhea
dilated pupils muscular twitching weight loss
depression loss of appetite
Fatal Cases
weak pulse irregular breathing coma
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lower body temperature retention of urine convulsions
Locoweed (Astragalus and Oxytropis spp.)
Eating the plant causes a variety of problems. Plants contain the
alkaloid swainsonine, which can cause 'locoism'. The common symptoms
are: impairment of the nervous and immune systems, depression,
dullness or excitement when disturbed. Abortion and birth
deformities may occur. Animals may become habituated to locoweed.
Swainsonine influences the vascular system and can cause heart
failure. This is a major poisonous range plant in the western United
States.
Nomenclature
Botanical name: Astragalus lentiginosus, Oxytropis lamberti
English Common name: Astragalus, purple locoweed
Botanical family name: Leguminosae
English family name: pea
Toxic parts: flowers, leaves, seeds, stems. The flowers of locoweeds
contain more swainsonine than the leaves. The immature pods contain
less swainsonine than the blooms, but this amount increases with
maturity.
Toxic chemicals: swainsonine, slaframine. Swainsonine, the chemical
involved in locoism, is found in several plants, including Astragalus
bisulcatus, A. lentiginosus, Oxytropis lambertii, and O. sericea.
This indolizidine alkaloid causes locoism in horses; it also causes
birth defect deformities in foals.
General symptoms of poisoning: depression, excitement when
disturbed, impaired nervous system function, abdominal swelling, loss
of appetite, generalized swelling, lack of coordination, may lead to
paralysis and death.
Climbing Nightshade, Black Nightshade, Potato (Solanum spp.)
Nightshade is a naturalized woody vine, sometimes grown as an
ornamental. The plant, especially in its green immature fruits,
contains steroidal alkaloids, which have caused poisoning in horses.
Potatoes are also in the nightshade family, containing the same
toxins. Most potato plants have been tested for lowered levels of
the toxins, and are generally safe. If a horse were to injest the
berries of the potato plant, however, toxic response should be
expected.
Nomenclature
Botanical name Solanum dulcamara, Solanum nigrum, Solanum tuberosum
English Common name: Climbing nightshade, Black nightshade, Potato
Botanical family name: Solanaceae
English family name: nightshade
Toxic parts: immature fruit, leaves
Toxic chemicals: Immature green berries of climbing nightshade
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contain parent steroidal alkaloid aglycones: 50% solasodine and 50%
of another aglycone thought to be soladulcidine. The total alkaloid
concentration has been found to be 0.030% of dry matter in the green
berries.
Two glycoalkaloids, alpha-solanine and alpha-chaconine, are the major
alkaloids in potatoes. The major effects are gastrointestinal tract
irritation and nervous system impairment. Exposing potato tubers to
light may increase the concentration of glycoalkaloids to 0.05% in
the tuber instead of the usual 0.008%.
General symptoms of poisoning: eating of the immature fruits can lead
to rapid respiration, feeble pulse, high temperature, dilated pupils,
then death.
Oaks (Quercus spp.) Red Oak, White Oak and Black Oak
Eating of acorns of any species of Oak can cause severe poisoning in
horses. The tannin compounds present in the acorns are present also
in the leaves, though to a lesser extent.
Nomenclature
Botanical name Quercus alba, Quercus rubra Quercus velutina
English Common name: white oak, red oak, black oak
Botanical family name: Fagaceae
English family name: beech
Toxic parts: acorns and leaves
Toxic chemicals: The toxic agents are polyhydroxyphenolic compounds
(tannins) including gallic acid, pyrogallol, and tannic acid. The
concentration of these compounds is higher in immature, green acorns
than in mature ones. The following quantities of phenolics were found
in acorns:
Oak species Total phenolics (% of total weight)
Quercus alba (white oak) 1.09 (0.41-2.54)
Quercus rubra (red oak) 3.72
Quercus velutina (black oak) 4.51 (3.29-6.13)
Black oak and red oak contain a greater total average of phenolics in
acorns than white oak.
General symptoms of poisoning: Eating the leaves and acorns can
cause toxic symptoms including loss of appetite, bloody diarrhea,
constipation, swelling, dehydration, leading to death.
Red maple (Acer rubrum)
Horses can be poisoned after they eat wilted red maple leaves. Signs
of poisoning are similar to those seen with the Brassica anemia
factor after animals ingest of plants of the genus (such as canola,
kale and cabbage).
Nomenclature
Botanical name Acer rubrum
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English Common name: Red maple
Botanical family name: Aceraceae
English family name: maple
Toxic parts: Eating of wilted leaves of red maple have caused
poisoning and death in horses. This toxicity is most prevalent from
June through October. Cases become symptomatic 3-4 days after eating
the leaves. Wilted leaves administered to a pony at the rate of 3.0
g/kg of body weight caused illness and death within 1-5 days. Freshly
harvested leaves did not cause any symptoms. Dried leaves remain
toxic for up to 30 days.
Toxic chemicals: toxic agent unknown
General symptoms of poisoning: rapid breathing, lack of oxygen in
blood, dehydration, depression, elevated heart rate, congested lungs,
swelling of kidneys, brown mucous membranes, brownish urine, brownish
blood, weakness, leading to coma and death.
Rhubarb (Rheum rhaponticum)
Rhubarb (Rheum rhaponticum) is a perennial cultivated plant. The
plant contains oxalate crystals, which have been reported to cause
poisoning when large quantities of raw or cooked leaves are eaten.
Anthraquinones (glycosides) have been implicated more recently in
poisoning. The stalks are widely used as preserves and are also eaten
raw, without problems. The toxic content is much lower in the stalks
than the leaves.
Nomenclature
Botanical name Rheum rhaponticum
English Common name: Rhubarb
Botanical family name: Polygonaceae
English family name: Buckwheat
Toxic parts: leaves
Toxic chemicals: Oxalates are contained in all parts of rhubarb
plants, especially in the green leaves. There is some evidence that
anthraquinone glycosides are also present and may be partly
responsible.
General symptoms of poisoning: abdominal pain, weakness and
drowsiness. Blood clotting is reduced.
Russian Knapweed, Yellow-Star Thistle
These plants cause 'chewing disease' in horses. Prolonged
consumption of the plants is required to produce the symptoms.
Russian knapweed is more toxic than yellow-star thistle. There are no
known treatments for horses once the symptoms appear. Chewing disease
becomes incurable once clinical signs are present.
Nomenclature
Botanical name Centaurea repens L. Centaurea solstitialis L.
English Common name: Russian Knapweed, Yellow-Star Thistle
Botanical family name: Compositae
English family name: Composite
Toxic parts: Leaves, stems, all parts
Toxic chemicals: toxic agent unknown
- Eating 1.8-2.5 kg/100 kg of body weight per day of Russian knapweed
causes poisoning after eating 59-71% of body weight of the plant
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material in about 30 days.
- Eating 2.3-2.6 kg/100 kg of body weight per day of yellow-star
thistle causes poisoning after eating 86-200% of body weight of the
plant material in about 54 days.
General symptoms of poisoning: constant chewing activity without
food intake, lack of coordination, unsteady gait, restlessness,
drowsiness, reduced water intake, leading to death.
St. John's Wort (Hypericum perforatum)
St. John's Wort is a naturalized herb that contains hypericin, which
is a primary photosensitizing chemical. Eating has caused skin
problems in horses and other animals. The skin problems occur on
white or light-colored skin, dark skin is not affected. Severe
symptoms such as convulsions, staggering, and coma have occurred. The
reaction is more severe if fresh plants are eaten, but dried plants
can also cause photosensitization, even though 80% of the hypericin
is lost.
Nomenclature
Botanical name Hypericum perforatum
English Common name: St. John's Wort
Botanical family name: Guttiferae
English family name: St. John's Wort
Toxic parts: flowers and leaves
Toxic chemicals: Hypericin, a fluorescent pigment, is a derivative of
naphthodianthrone. The pigment is contained in small black dots that
are just visible to the naked eye on leaves and petals. The chemical
is a primary photosensitizer because the photodynamic action occurs
in the skin.
General symptoms of poisoning: loss of appetite, staggering gait,
peeling of the skin and in severe cases, coma
Sensitive Fern (Onoclea sensibis)
Sensitive fern is often abundant in low, wet areas, and has been
implicated in the poisoning and death of horses. When horses eat hay
containing dried sensitive fern, resulting symptoms were similar.
Nomenclature
Botanical name Onoclea sensibilis
English Common name: sensitive fern
Botanical family name: Polypodiaceae
English family name: fern
Toxic parts: Leaves
Toxic chemicals: Toxic agent unknown
General symptoms of poisoning: Eating sensitive fern, either in hay
or as forage produces the following symptoms: difficulty in eating,
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falling down, walking as if blind, rubbing against objects, and may
lead to death. Old horses are affected more than younger ones.
Horses that are worked and are fed a grain supplement, in addition to
hay that includes the fern, appear unaffected. Recovery may occur if
the horses are given good hay and grain before serious nervous
symptoms develop.
Sorghum or Milo, Sudan Grass, and Johnson Grass (Sorghum spp.)
Sorghum, Johnson Grass, etc. can contain a cyanogenic glycoside that
can produce HCN during times of stress or if damaged by frost or
chewing. Modern sorghums have been developed for their low HCN
potential and are normally safe. Sorghum can also accumulate toxic
levels of nitrates.
Nomenclature
Botanical name Sorghum bicolor ( L.), Sorgham halepense, Sorghum
sudanense
English Common name: Sorghum
Botanical family name: Gramineae
English family name: grass
Toxic parts: leaves and stems
Toxic chemicals: dhurrin; nitrate. A cyanogenic glycoside, dhurrin,
is found in Sorghum spp. After chewing has damaged the plant, plant
enzymes convert the glycoside to other chemicals, including HCN.
Cyanide, which is lethal, can be released into the animal's system.
Since HCN is volatile, silage made from this plant is generally safe.
General symptoms of poisoning: HCN causes damage to the lumbar and
sacral segments of the spinal cord in horses after they eat sorghum.
Large quantities of sediment occur in the urine. If forced to move,
affected horses sway from side to side and dribble urine, a condition
known as 'sorghum cystitis ataxia'. Other symptoms include an
extremely enlarged bladder and patchy softening of the tissue of the
brain (encephalomalacia) with associated nerve (axonal) degeneration.
Damage is permanent. When fed sorghums during early pregnancy, mares
have aborted. Symptoms are the result of oxygen loss due to cellular
damage (cytotoxic hypoxia), leading in severe cases to death from
asphyxiation. Other symptoms include increased respiration, irregular
pulse, frothing at the mouth, and staggering.
Yew (Taxus spp.)
English yew (Taxus baccata) is an introduced ornamental shrub. This
shrub has caused poisoning and death in horses. Eating leaves, bark,
or seeds can cause poisoning in all animals. The fleshy fruit pulp is
considered to be nontoxic (or low in toxicity). Taxine, a complex of
alkaloids, is found in the plant. Animals should not have access to
the shrub or clippings of the branches.
Nomenclature
Botanical name Taxus baccata, Taxus canadensis
English Common name: English Yew, Canadian Yew, Japanese Yew
Botanical family name: Taxaceae
English family name: yew
Toxic parts: leaves, pollen, seeds. All parts of the plant contain
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significant amounts of the alkaloids, with the exception of the
fleshy part of the fruits, which is regarded as nontoxic or low in
toxicity. The seeds are toxic. Eating the entire fruits without
removing the seeds can cause poisoning. Toxicity is not reduced with
drying. Hedge clippings from these plants are as toxic as fresh
plants.
Toxic chemicals: Taxine (taxin) is a complex mixture of alkaloids
that is rapidly absorbed from the digestive tract and interferes with
heart action. The lethal dose is estimated at 0.5-2 g/kg for horses.
General symptoms of poisoning: Eating yew results in the following
symptoms: coldness, a rapid and then weak pulse, excitability, then
collapse followed by death. Abdominal pains, confusion, staggering
gait and lack of coordination may also be noted.
Shrubs, Flowers and Trees Known To Be Safe
African Violet (Saintpaulia)Aglaonema (Botanic name)
Ajuga Reptans (Botanic name)
Albizzia (Botanic name)
Alstoemeria (Botanic name)
Aluminum Plant (Pilea cadierei)
Amaryllis Belladonna (Botanic name)
Anemone (Botanic name)
Angel Wing Begonia (Species)
Artillery Plant (Pilea Microphylla)
Asparagus Fern (A. setaceus or sprengeri)
Aster, Giant (Townsendia sericea)
Baby's Blanket (Thymus serpyllum)
Baby's Breath (Gypsophyla)
Baby Tears (Helxine soleirolii)
Bachelor Buttons (Centaurea cyanus)
Bamboo, common (Phyllostachy aurea)
Bird's Nest Fern (Asplenuim nidus)
Bishop's Weed (Aegopodium podagaria)
Blue Spruce (Picea pungens)
Boston Fern (Nephrolepsis exalta)
Butterfly Bush (Buddleia davidii)
Camellia (Thea japonica)
Canna Lily (Canna generalis)
Canterbury Bells (Campanula)
Carob Tree (Ceratonia siliqua)
Cockscomb (Celosia argentea)
Coleus (Species)
Creeping Charlie (Plectranthus australis)
Creeping Charlie (Lysimachia nummularia)
Creeping Charlie (Pilea nummulariifolia)
Crocus, Spring blooming (Species)
Dahlia (Species)
Dandelion (Taraxacum officinale)
Douglas Fir (Pseudosuga taxifolia)
Easter Lily (Lilium longiflorum)
Elephant Ear (Bergenia cordifolia)
Fir (Abies or pseudotsuga)
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Forget-me-nots (Myosotis)F
Forsythia (Botanic name)
Fruitless Mulberry (Morus)
Fuchsia (Species)
Gardenia (Jasminoides)
Gloxinia (Sinningia speciosa)
Gourd (Cucurbitaceae)
Grape Hyacinth (Muscari species)
Hemlock, Tree (Tsuga species)
Hen and Chickens (Sepervivum tectorum)
Hen and Chicks (Echeveria)
Hibiscus (Botanic name)
Hollyhock (Althaea rosea)
Honey locust (Gleditsia triacanthos)
Lilac (Syringa)
Locust Pods Tree (Ceratonia siliqua)
Manzanita (Arctostaphylos)
Maple Tree (Silver, Acers Species)
Mock Orange (Philadelphus species)
Mock Orange (Pittosporum tobira)
Mountain Ash (Sorbus aucuparia)
Mulberry Tree (Morus species)
Nasturtium (Tropaeolum majus)
Petunia (Species)
Phlox (Botanic name)
Purple Passion Vine (Gynura aurantiaca)
Red Bud (Cercis Canadensis)
Rose of Sharon (Hibiscus syriacus)
Silver King (Aglaonema)
Snake Plant (Sansevieria Trifasciata)
Snapdragon (Antirrhinum species)
Snowball Bush (Viburnum)
Sphagnum Moss (Botanic name)
Strawflower (Helichrysum bracteatum)
Swedish Ivy (Plectranthus australis)
Sycamore (Platanus)
Torch Lily (Kniphofia)
Wandering Jew (Zebrina pendula)
Weigelia (Botanic name)
Willow (Salix)
Xylosma (Botanic name)
Yucca (Botanic name)
Zebra Plant (Calathea zebrina)
Zebra Plant (Cryptanthus zonatus)
Zinnia (Botanic name)
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