Colorado rubberweed
General poisoning notes:
Colorado rubberweed (Hymenoxys richardsonii) is a native herb found in the southern prairies. This plant has caused poisoning and death in sheep, goats, and occasionally cattle. Sheep and goats consume this plant when there is little else to eat. Poisoning is therefore most frequent in spring and late autumn, when other forage is reduced. Cattle are poisoned less frequently because they find the plant unpalatable (Cheeke and Schull 1985).
Nomenclature:
Scientific Name: Hymenoxys richardsonii (Hook.) Cockerell
Vernacular name(s): Colorado rubberweed
Scientific family name: Compositae
Vernacular family name: composite
Hymenoxys richardsonii (Hook.) Cockerell
Geographic Information
Alberta, Saskatchewan
Toxic parts:
All parts, leaves, stems
Notes on Toxic plant chemicals:
Hymenovin (hymenoxon) is a sesquiterpene lactone that contains an alpha-methylene-gamma-lactone moiety. This moiety inhibits the enzymatic capability of adenylate cyclase by alkylation of its thiol group. The inhibition can disrupt the cellular transmission of external signals to the internal regulatory proteins. Mercaptans, such as cysteine, may be used in treatment by partly detoxifying the moiety before it can damage cellular enzymes (Elissalde and Ivie 1987). The oral LD-50 of hymenovin (hymenoxon) is 2.9-8.5 g/kg in sheep (Cheeke and Schull 1985).
Toxic plant chemicals:
Hymenovin
Hymenovin
Animals/Human Poisoning:
Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.
Cattle
Goats
Sheep
General symptoms of poisoning:
Death, kidney, congestion of, liver, congestion of, lungs, congestion of, vomiting.
Notes on poisoning:
Symptoms of ingestion include violent vomiting, hence the name spewing sickness. Sheep may have a green stain around the mouth. Vomited material can be inhaled, which can lead to inhalation pneumonia, permanent lung damage, or death. Lesions in the gastrointestinal tract, liver and kidney congestion, and lung damage occur. Frequent coughing and sneezing occur (Parker, Cheeke and Schull 1985).
