Marsh horsetail
General poisoning notes:
Marsh horsetail (Equisetum palustre) is a native horsetail growing across Canada. This plant has poisoned cattle and, rarely, sheep. In addition to thiaminase, it contains an alkaloid, that causes the toxicity (Kingsbury 1964, Cooper and Johnson 1984).
Nomenclature:
Scientific Name: Equisetum palustre L.
Vernacular name(s): marsh horsetail
Scientific family name: Equisetaceae
Vernacular family name: horsetail
Equisetum palustre L.
Geographic Information
Alberta, British Columbia, Manitoba, New Brunswick, Newfoundland, Northwest, Territories, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan, Yukon Territory
Notes on Poisonous plant parts:
Marsh horsetail has separate fertile and sterile stems. Unlike field horsetail, both types of fronds are greenish, with the added fruiting sporangia body on top of the fertile frond.
Toxic parts:
Leaves, stems.
Notes on Toxic plant chemicals:
Palustrine, an alkaloid, has been found in marsh horsetail. This alkaloid may contribute to the poisoning of cattle by this plant. Thiaminase activity is usually not a problem in ruminants because thiamine is produced in the rumen. Therefore, the presence of alkaloids is suspected to cause the toxic responses. The alkaloid content varies greatly (96-302 mg/100 g of dry weight). Frosted plant material quickly loses most of its alkaloid content, whereas air-dried marsh horsetail can keep its alkaloid content for years (Frohne and Pfander 1983).
Toxic plant chemicals:
Palustrine, thiaminase.
Thiaminase
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:
Diarrhea
Horses
Sheep
General symptoms of poisoning:
Diarrhea, muscle, weakness of, sweating.
