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 White Snakeroot
Ageratina altissima var. altissima
The
first section poses an interesting warning about this
plant that is very poisonous
taken from the link
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The
second section comes from a vet school and talks about the plant's effects
on various farm animals and pets with a part on how to
control the plant.
taken from the link
☼
Plant Type: This is a herbaceous plant, it is a
perennial which can
reach 150cm in height (60inches).
Leaves: The leaf arrangement is opposite. Leaves can reach 18cm
in length (7inches). Leaves can be as wide as 12 cm (5inches). Each leaf is
toothed and ovate, sometimes
nearly cordate. The may be
slightly hairy especially on the underside along the main veins.
Flowers: The flower parts are not discernable with the naked
eye and are up to 0.4cm wide (0.16 inches). They are white. Blooms first appear
in mid summer and continue into mid fall. The small flowers have five parts and
are in tight heads of nine to twentyfive flowers. The heads in slightly rounded
clusters.
Habitat: Rich woods and disturbed areas.
Range: Eastern US into Canada
Medical Uses: Native Americans used the plant to treat diarrhea and
kidney stones and may have used smoke from the leaves to revive unconscious
patients. Warning: The plant is considered poisonous and hungry cows may
eat it and give milk that is toxic to humans.
White snakeroot is an erect, branched herb usually about 3 feet tall but
varying from 1 to 5 feet. It has slender, round stems and branches bearing
pointed, oval, oppositely placed leaves. These leaves, 3 to 5 inches long and
petioled, are sharply toothed on the margins. Each leaf has 3 main veins that
show prominently on the underside. The roots are fibrous, coarse, and shallow.
In late summer, numerous small heads of minute white flowers appear at the
top of the stem and the ends of the branches. These flower heads, except that
they are white, are almost exactly like the flower heads of the familiar
ageratum of gardens. Later the flowers are replaced in the heads by small black
seeds each with a crown of soft white hairs.
Conditions of poisoning
An animal may die from eating either a large amount of white snakeroot at one
time or small amounts over a long period. The eating of small quantities more or
less continuously gives rise to the animal disease known as trembles. It is also
the cause of the well-known and much-feared milk sickness of man -- a disease
that is contracted from drinking milk or eating milk products from poisoned
cows. Milk sickness claimed thousands of lives in the early 1800s, perhaps the
most well-known victim being Abraham Lincoln's mother. Nursing calves and lambs
may die from their mothers' milk contaminated with snakeroot even though the
mother animals show no signs of poisoning. Cattle, horses, and sheep are the
animals most often poisoned.
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During the dry period of late summer, animals should not be pastured in woods
or fields where there is white snakeroot. If the pasture is known to be
infested, animals should be moved out of it within the first few days of July
and should not be returned to it until the following year.
Eradication of white snakeroot is not easy. Chemical weed-killers cannot be
used satisfactorily, because they endanger trees and other plants of the
pasture. The best way to reduce the number of the plants is to pull them out by
the roots and burn them; the best time to do this is in September, when the
plants are more easily identified by their white blossoms. If the plants are
pulled after a hard rain while the ground is soft, the shallow roots come out
readily.
Clinical signs
White snakeroot can endanger the lives of persons and animals other than
those that have actually eaten the plant.
In cattle and sheep:
Although animals that have fed on white snakeroot may be listless and
somewhat inactive at first, the first noticeable manifestations of poisoning are
loss of weight and trembling following exercise. Trembling is especially marked
in the muzzle and legs. As poisoning progresses, cattle lose appetite, become
constipated, lose weight, and gradually become weaker until they are not able to
stand. Additional signs may include a peculiar odor to the breath and urine,
excessive salivation, and quickened, difficult breathing. Later, complete
relaxation without tremors and coma are seen, with death following in 2-10 days.
The clinical signs that are exhibited by poisoned sheep are similar to those
shown by cattle. Death may occur in a few days or may be delayed.
In cases of chronic poisoning, post-mortem examination generally reveals
extensive degenerative changes in the liver and kidney.
In horses:
The onset of clinical signs in white snakeroot poisoned horses is within 2
days to 3 weeks after initial ingestion (usually after at least several days of
ingestion). The major effects are related to congestive heart failure. Tremors
are inconsistently observed in horses with white snakeroot poisoning. Horses may
stand with legs wide apart. Sweating may be evident especially between rear
legs, and stumbling in the rear legs may be noted when horses are turned. Severe
depression, bloody urine, and/or choking may also occur. Sometimes swelling is
present in the lower neck area, near the thoracic inlet. They may exhibit a
jugular pulse and a rapid heart rate. Changes in electrocardiogram include
increased heart rate, ST elevation, and variable QRS complexes, and ventricular
premature beats. Cardiac arrhythmias are often present.
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