Prickly lettuce
General poisoning notes:
Prickly lettuce (Lactuca scariola) is a naturalized herb found across parts of southern Canada. In the western United States, cattle developed pulmonary emphysema after ingesting the plant. The injury appears to be associated with a deficiency, because the toxicity develops after the cattle have fed on dry rangelands. When they are subsequently moved to lush, autumn pasture, some cattle feed ravenously on the prickly lettuce regrowth and, in a few days, the symptoms may develop (Beath et al. 1953).
Nomenclature:
Scientific Name: Lactuca scariola L.
Vernacular name(s): prickly lettuce
Scientific family name: Compositae
Vernacular family name: composite
Lactuca scariola L.
Geographic Information
Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec.
Notes on Poisonous plant parts:
Mature plants and dried plant material are reported to be harmless. Regrowth of the plants in autumn has caused poisoning in field cases in the western rangelands of the United States (Beath et al. 1953).
Toxic parts:
Young shoots.
Toxic plant chemicals:
Unknown chemical.
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:
Breathing, labored, emphysema, weakness.
Notes on poisoning:
Symptoms include pulmonary emphysema, characterized by weakness and difficult breathing. Postmortem examination shows the lung tissue inflamed, with almost complete destruction of the air-cell tissue (Beath et al. 1953).
