Transcript PowerPoint - ELKRIDGE HARFORD HUNT

Types of toxins in plants
Alkaloid – any number of bitter organic substances, such as
caffeine, morphine, quinine and strychnine, having alkaline
properties and containing nitrogen. Found in plants and often used
as drugs and stimulants, but can have a toxic effect on the human
or animal system.
Prussic Acid - (hydrocyanic acid) a deadly poison which is
produced under certain conditions: frost, drought, trampling,
bruising, wilting. Ecological conditions are factors in the formation
of prussic acid. Plants grown in poor soil have less acid than when
grown in nitrate rich soil. These plants seem to lose their poison
when thoroughly dry, as the acid is very volatile and passes into the
air while the plant is drying.
Prussic acid is a cyanide compound that can kill animals within
minutes of ingestion under the right circumstances. Cyanide
interferes with the oxygen-carrying function in the blood, causing
animals to die of asphyxiation. Symptoms include difficult
breathing, excess salivation, staggering, convulsions and collapse.
Affected animals will have bright cherry red mucous membranes
from the cyanide. Ruminants are more susceptible than horses or
swine because they consume large amounts of forage quickly and
the rumen bacteria contribute to the release of the cyanide from
consumed plant tissue.
Most Common Poisonous Plants in MD and PA
In Order From Most to Least Toxic
Hemlock/water hemlock
All parts are toxic, a piece the size of a pea can kill a human.
Water hemlock, trampled into water, has been known to kill
livestock. Toxic year-round, most likely to be eaten in early
spring.
Symptoms: salivation, bloating, colic, dilation of pupils,
rolling of eyes, labored respiration, diminished frequency of
breathing, irregular heart action, loss of sensation, uncertain
gait, falling, ending with complete paralysis, and death
within a few hours.
Ornamental yew/Japanese yew
All parts contain toxic alkaloids, ¼ lb of clippings will kill. People,
often not knowing better, will place trimmings in animal
enclosures. Yew is often planted as an ornamental plant around
houses. Having the shrubs too close to fencelines is a common
way that animals come in contact with them.
Symptoms: colic, diarrhea, tremors, dilated pupils, respiratory
difficulty, weakness, fatigue, collapse, coma, convulsions,
circulatory failure, and death. Death is sometimes so rapid that
few well-developed symptoms appear. Survival is rare.
Mountain Laurel, Rhododendron, and Azalea
All parts toxic, 2 or 3 leaves may produce severe toxicosis.
Because they retain their green leaves year-round, most toxicoses
occur in the winter and early spring, when other forage is
unavailable. Grows in shady areas, and often planted as an
ornamental.
Symptoms: disinclination to eat, repeated swallowing, profuse
salivation, grating of the teeth, frothing at the mouth, loss of
energy, slow pulse, low blood pressure, incoordination, dullness,
depression, stupor and death.
Nightshade (black, bittersweet, deadly, silverleaf), horse nettle,
Jerusalem cherry, ground cherry
Generally, the leaves and green fruits are toxic. Eating the juice
from wilted leaves may be especially toxic. Poisoning by these
species occurs primarily when animals are confined in overgrazed
fields where the plants are abundant. The hazard of poisoning
varies, depending on the plant species, maturity of plants, and
other conditions. One to ten pounds can be fatal.
Symptoms: Colic, convulsions, dilated pupils, weakness, depression,
death from paralysis of the lungs.
Wild cherry, chokecherry, Sudan grass, sorghum
When plants are damaged due to frost, drought, bruising,
trampling, wilting, they produce prussic acid. This is found mostly in
the leaves, bark, and shoots. Most common exposure to wild cherry
and chokecherry is when limbs are blown down or are trimmed and
thrown into animals’ enclosures. They are common trees in many
areas, and are often found in woods edges. They kill by inhibiting
the red cells’ ability to transport oxygen. When dried, there is no
longer any danger.
Symptoms: anxiety, staggering, falling down, convulsions, rolling of
eyes, tongue hanging out, colic, difficulty breathing, and death by
suffocation.
Red maple
Wilted red leaves contain toxin, can remain toxic for 30 days after
falling. Early spring and fall are times to watch for it. A common tree,
mostly in damp areas.
Symptoms: similar to oak poisoning.
Oak
Toxin is ingested by eating young shoots, leaves, and acorns if eaten
in quantitiy. A common tree in most areas.
Symptoms: anorexia, constipation becoming diarrhea, colic, thirst,
and excessive urination.
Black locust
Toxin is ingested by eating inner bark, roots, wilted leaves, and
seed pods. A common tree in many areas.
Symptoms: stupor, depressed heart action, weak pulse.
Black walnut
Pollen in spring can cause allergic respiratory reactions and laminitis.
Laminitis and colic occur from eating bark or fallen walnuts. Standing
in walnut shavings as bedding causes laminitis, too. A common tree
in many areas.
Bracken fern
All parts are toxic, usually eaten in the fall when pasture is poor, or
in hay. Drying does nor reduce toxicity. Inhibits uptake of vitamin B1.
Must eat it frequently for a period of 30 – 60 days for toxicity to build
up.
Symptoms: loss of appetite, and loss of coordination.
Horsetail
Usually eaten in hay, must be eaten for 2 – 5 weeks for symptoms
to appear, The alkaloid equesetin causes thiamin deficiency.
Symptoms: unthriftiness, diarrhea, loss of weight, loss of muscular
control, followed by swaying and staggering. Animal falls and
cannot rise. Violent struggle weakens the animal and death is
caused by exhaustion.
Jimsonweed
Whole plant is toxic, seeds are particularly poisonous. Horses
usually avoid the plant due to its noxious odor and taste.
Poisoning most often occurs from the leaves of young plants
getting into hay, or pasture with nothing else to eat.
Symptoms: rapid pulse, rapid breathing dilated pupils,
restlessness, nervousness, muscular twitching, drinking a lot,
diarrhea, loss of appetite, weight loss, in fatal cases, the pulse
remains rapid but weak, breathing becomes slow and irregular,
body temperature becomes subnormal, and convulsions or
coma precede death.
Spreading dogbane/Indian hemp
Whole plant is toxic, eaten only when pasture is poor, early spring
or late fall.
Symptoms: increased temperature and pulse, warm body, cold
extremities, sweating, dilation of pupils, discoloration of mouth and
nostrils, sore mouth. The animal refuses to drink for 24 hours
preceding death.
Cocklebur
Seeds and seedlings contain the toxin. It is not lost upon drying.
Most hazardous at seedling stage because of its toxicity as well as
palatability. Mature plants are seldom eaten due to bitterness and
rough texture.
Symptoms: signs develop within 2 – 24 hours, loss of appetite, rapid
weak pulse, difficulty breathing, muscular weakness, prostration,
and spasmodic contraction of leg and neck muscles. Potentially
lethal hypoglycemia may occur.
Pokeweed
Whole plant is toxic, although root is most toxic. Animals may feed
on poke plants in the spring when the plants are succulent or if
the grass is very short, they may browse on the tips of the plants.
Unless there is almost nothing else to eat, the animals will not eat
the tops or the berries later in the summer. Pokeweed is harmless
when it is dried.
Symptoms: horses rarely eat enough to cause more than a colic.
May Apple
Entire plant toxic, except “apple” when ripe. Not normally eaten
but some animals develop a taste for it. Must eat continuous
large amounts to show symptoms. Grows in moist, shady,
wooded lowlands.
Symptoms: colic, bloody feces, convulsions, and death.
Buttercup
Fresh leaves and tops contain toxin. This toxin is an acrid volatile
substance that leaves the plants as they dry, so buttercups in hay
are harmless. They have a very bitter taste and are usually only
eaten by accident, when they are pulled up from soft, damp earth
along with other plants. They must be eaten in quantity to be
toxic.
Symptoms: salivation, loss of appetite, colic, diarrhea, and slow
pulse.
Bouncing Bet
Toxin irritates mucous membranes of digestive tract and cause colic.
Common horse chestnut
Nut is toxic.
Wild Onion
Entire plant contains toxins. Toxin causes rupture of the red
blood cells. Horses are only slightly susceptible to the toxin. Most
common time for poisoning occurs in cool spring weather when
grass growth is delayed and wild onions are available in
comparatively large quantities for grazing.
Symptoms: urine discoloration from red wine to almost black.
Muscle weakness, rapid breathing, and rapid heart rate may be
noted if hemolysis is sufficiently severe.
1. What is more toxic, yew, or buttercup? Yew
2. How do horses often come in contact with yew?
Yard
trimmings thrown over a fence, and yew planted near fences
and barns.
3. Why will horses sometimes eat bitter, foul-tasting toxic plants?
When there is little else to eat in a field, especially in spring,
when plants are young and tender.
4. In what condition do cherry leaves have to be in order to be
toxic? They have to be wilted or damaged
5. What’s a common way that horses are exposed to toxic cherry
leaves? When a tree or branches fall in a pasture.
6. What trees have toxic seeds or nuts? Oak, black locust, black
walnut, horse chestnut.
7. What toxic plant is most commonly eaten in hay? Horsetail
jimsonweed, and bracken fern
8. What toxic plants are harmless when dried? Pokeweed,
buttercup
9. What plants are needed to be eaten in large quantities in order
to be toxic? May apple, buttercup
10. Have you noticed any of these plants in pastures in this area?
Should you be concerned? Why, or why not? Common ones are:
wild cherry, red maple, oak, black locust, black walnut,
cocklebur, pokeweed, buttercup, wild onion.
Most are not concerning, because horses won’t eat them because
of bitter taste or low palatability. Others need to be eaten in very
large quantities. Keeping pastures healthy, and feeding
supplemental hay in fields can reduce the risk. Removing fallen
nuts, and fallen cherry branches can help.