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
Oxytropis sericea Nutt.
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.
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.
