Locoweed (Oxytropis sericea)
General poisoning notes:
Locoweed (Oxytropis
sericea) is a native herb in western Canada. This plant has caused a number
of problems in cattle, horses, and sheep. Swainsonine, an indolizidine
alkaloid, inhibits alpha-mannosidase in animal bodies, which can lead to
disruption of cellular function. Locoism is a chronic disease that causes
depression, incoordination, and nervousness under stress. Death can result. The
cellular problems occur most readily in tissues of the nervous system. Pregnant
animals often abort or give birth to young with congenital deformities.
Congestive right heart disease occurs at high altitudes (above 2190 m) in
cattle. Right ventricular hypertrophy and dilation, subcutaneous edema, and
pulmonary hypertension are significant symptoms (James 1983, Cheeke and Schull
1985, James et al. 1986, Panter et al. 1988).
Nomenclature:
Scientific Name: Oxytropis sericea Nutt.
Vernacular
name(s): locoweed (Oxytropis sericea)
Scientific family
name: Leguminosae
Vernacular family
name: pea
Geographic Information
Alberta, British
Columbia, Saskatchewan, Yukon Territory.
Notes on Poisonous plant parts:
The blooms and
mature fruit of locoweed have higher quantities of the toxin swainsonine than do
the leaves. The concentration of this toxin remains constant in leaves
throughout the grazing season (Ralphs et al. 1986.)
Toxic parts:
Flowers, leaves, mature
fruit, seeds, stems.
Notes on Toxic plant chemicals:
Swainsonine, an
indolizidine alkaloid, inhibits alpha-mannosidase in the animal''s body.
Inhibition results in the accumulation of oligosaccharides in cells because
glycosidases remove their respective sugars until a mannose residue is reached.
Hydrolysis of the carbohydrate then stops. Eventually disruption of cellular
function results. The effect of swainsonine on alpha-mannosidase is reversible
when locoweed is no longer consumed. However, advanced clinical signs are
irreversible because axon degeneration occurs. The central nervous system is
most sensitive to mannose accumulation (Cheeke and Schull 1985).
Toxic plant chemicals:
Slaframine, swainsonine.
Chemical
diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops
Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia,
Canada.
Animals/Human Poisoning:
Note: When an
animal is listed without additional information, the literature (as of 1993)
contained no detailed explanation.
Cattle
General symptoms of
poisoning:
abdominal
edema
belligerence
coat,
rough and dry
death
depression
diarrhea
duodenum,
edema of
eyes,
dull
gall
bladder, enlarged
incoordination
jaw
(lower), edema of
thorax
(ventral),edema
throat,
edema of
ventrical
(right),edema
Horses
General symptoms of
poisoning:
Arthrogryposis,
coat, rough and dry, depression, gait, unsteady, incoordination, nervousness
Sheep
General symptoms of
poisoning:
Abortion,
carpal joint, flexure, coat, rough and dry, death, depression, eyes, dull, incoordination,
nervousness, recumbency.
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