Locoweed

For other uses, see Locoweed (disambiguation).

Locoweed (also crazyweed and loco) is a common name in North America for any plant that produces swainsonine, an alkaloid harmful to livestock. Worldwide, swainsonine is produced by a small number of species, most of them in three genera of the flowering plant family Fabaceae: Oxytropis and Astragalus in North America,[1] and Swainsona in Australia. The term locoweed usually refers only to the North American species of Oxytropis and Astragalus, but this article includes the other species as well. Some references may incorrectly list Datura as locoweed.[2]

Locoweed is relatively palatable to livestock, and some individual animals will seek it out. Livestock poisoned by chronic ingestion of large amounts of swainsonine develop a medical condition known as locoism (swainsonine disease, swainsonine toxicosis in North America) and pea struck in Australia.[3] Locoism is reported most often in cattle, sheep, and horses, but has also been reported in elk and deer. It is the most widespread poisonous plant problem in the western United States.[1][4]

Most of the 2,000 species of Astragalus, including many that are commonly known as locoweeds, do not produce swainsonine. Some species, including a few that produce swainsonine, accumulate selenium. This has led to confusion between swainsonine poisoning and selenium poisoning due to this genus.[5]

  1. ^ a b Cite error: The named reference RalphsJames1999 was invoked but never defined (see the help page).
  2. ^ "Sacred Datura (Locoweed) on North Kaibab Trail Grand Canyon - don't even think about smokin' this s**t uff". October 19, 2006.
  3. ^ Pritchard DH, Huxtable CR, Dorling PR (March 1990). "Swainsonine toxicosis suppresses appetite and retards growth in weanling rats". Research in Veterinary Science. 48 (2): 228–30. doi:10.1016/S0034-5288(18)30995-0. PMID 2110378.
  4. ^ "ARS and New Mexico Scientists Take a Long Look at Livestock and Locoweed : USDA ARS".
  5. ^ "Ranchers despise locoweed". Colorado Arts and Sciences Magazine. August 28, 2016. Retrieved May 13, 2024.