Page 945 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Poisonous Plants of the Europe Chapter | 62 897

VetBooks.ir COLCHICUM AUTUMNALE L (LILIACEAE stems arising from a thick taproot. It is a tall, branched
plant with white flowers. This biennial plant is most often
OR COLCHICACEAE FAMILY)
noticed during its second year of growth when it bolts
Common Names: Colchium, Meadow
Saffron, Autumn Crocus, Wonder Bulb, and and can reach heights of less than two meters. The poison
hemlock usually has only one fleshy taproot, there are no
Naked Ladies pithy partitions in a hollow area at the juncture of stem
and root, and stem and upper stem leaves are divided.
Colchium autumnale is locally abundant in meadows Leaves resemble parsley, and they have a parsnip odor
(meadow saffron; autumn crocus) throughout most when crushed. Many small white flowers are arranged in
European countries. It is a perennial herb, ovoid under- an umbel in florescence. Poison hemlock stems have pur-
ground corm covered with brown membrane or scales. ple blotches, a characteristic that distinguishes it from
Large leaves, lanceolate, basal, ovate, smooth, ribbed, wild carrot. Also, poison hemlock’s leaves are more angu-
appear in spring and die back before flowering (Kahn, lar that those of wild carrot. This is probably more com-
2010). mon that spotted water hemlock and found in drier, more
upland habitats. It is found in roadside ditches and in
Toxicity damp waste areas.
All parts of the plant C. autumnale contain the alkaloids
colchicine and colchiceine, of which the former is more Toxicity
toxic. The colchicine exists in all parts of the plant, but
Poison hemlock is one of the most toxic members of the
its highest concentration is in the bulb (B0.8% by
plant kingdom. The concentrations and the relative ratio of
weight). The pale purple flowers contain approximately
different Conium alkaloids appear to depend on different
0.1% colchicine by weight. Both alkaloids withstand stor-
factors such as temperature, moisture, time and age of the
age, drying (persist in contaminated hay), and boiling. At
plant. It contains piperidine alkaloids (coniine and cyana-
doses of 0.25 mg/kg body weight (BW), colchicine has a
pine) and other compounds that are capable of poisoning
purgative effect. At higher doses, colchicine is a potent
livestock, poultry, and humans. The consumption of vary-
gastrointestinal toxin and causes intractable multiorgan
ing parts of the plants (leaves, fruits) can cause different
failure. The European native is located in wet meadows
degrees of clinical effects. The stems, leaves, and mature
with poisoning occurring during the spring. Poisoning of
fruits are toxic. All parts contain the toxin, especially in
animals in the spring involves ingestion of the young
young plants. The leaves are more dangerous in spring,
leaves, whereas in the autumn the flowers of plants grow-
and the fruit is the most dangerous in fall. There appears to
ing wild in pastures are implicated (Humphreys, 1988).
be different susceptibility to toxicity between species.
Clinical Presentation
Poisoning primarily affects cattle but can affect horses Clinical Presentation
and pigs raised on pasture. Clinical signs appear approxi- Symptoms are gastrointestinal irritation and neurological
mately 48 h after ingestion. In cattle, the clinical signs of effects (nervousness, trembling, loss of coordination, stag-
intoxication are predominantly related to the digestive gering, and coldness of the extremities), hyperpnea, and
tract and are characterized by salivation, dysphagia, colic, tachycardia (Lorgue et al., 1996). Eventually, depression,
abdominal pain, diarrhea, and fetid feces that are green or coma and death occur from respiratory failure. Birth
black with tenesmus. Death occurs from cardiorespiratory defects may also occur. In general, animals can recover
failure and may be delayed for several days depending of within hours.
the amount of plant ingested. The visible postmortem Hemlock is more toxic to cattle than to other animals.
finding is gastroenteritis. Lesions that appear are edema Fresh plants collected at the same site were lethal to cows
and intestinal bleeding. In the horse, abdominal and tho- at the dosage of 5.3 g plant/kg bw. The general symptoms
racic serous effusions also occur. of poisoning in cattle are: arthrogryposis, depression, diar-
rhea, gait incoordination, lateral rotation of limbs, muscle
spasms, salivation, teeth grinding, torticollis, trembling,
CONIUM MACULATUM (APIACEAE
coffee-colored urine and vomiting. Congenital skeletal
(FORMALLY UMBILLIFERAE) FAMILY) malformations in calves from ingestion of hemlock have
been reported (Keeler and Balls, 1978). Sheep and goat
Common Name: Hemlock
are also affected when fresh plant material is ingested.
Hemlock (Conium maculatum) is a glabrous, branching The ingestion of hemlock by pigs leads to the follow-
biennial herbaceous plant, with hollow purple-spotted ing clinical signs: ataxia, tremors, severe lacrimation,