Locoweed
(Astragalus and Oxytropis species)

Poisonous to Horses

Toxic parts and chemical: toxicity from selenium
accumulation and swainsonine (an alkaloid)

Symptoms of Poisoning: nervous system swelling
from the alkaloid swainsoine if the plant is fresh and
selenium accumulator if dried locoweed (has less
swains nine), is consumed for 2 weeks. Symptoms
occurring include: aimless wandering, weight loss,
lack of coordination and altered gait, salivation,
weight loss, vision dysfunction and lethargy
followed by extreme startle to stimuli appearing
“loco.” Stallions will become infertile and mid to late
term mares will abort.  

Treatment includes removal from toxic plant,
administer laxatives to remove plant residue, give
sedative and keep the horse as quiet as possible.
Early treatment is important and prolonged and
advanced symptoms can cause disability and death.
Keeping Your Miniature Horse Healthy
locoweed
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