Locoweeds are perennial herbaceous plants composed of Astragalus spp. and Oxytropis spp. known for poisoning livestock. Locoweeds are toxic in all stages of growth, and whether it is fresh or dried. They both contain swainsonine, a toxic indolizidine alkaloid. Swainsonine is produced by fungal endophytes that contaminate locoweeds.
In addition to alkaloids, locoweeds can also accumulate excessive concentrations of selenium. Symptoms are usually seen after consumption of large amounts for 2 to 9 weeks. Signs last for several weeks. Young animals are most susceptible. Occasionally horses can recover however it is generally thrifty and will eat locoweed to the exclusion of other forage if returned to infested pasture.
Locoweeds are a large concern for ruminants living in the rangelands of the western United States, Asia, and South America. Consumption of locoweeds causes display behavioral disorders, gait abnormalities, and neurological symptoms such as ataxia, difficulty standing, standing abnormally, and leg paresis.
- Abnormal Behavior
- Infertility
- Abortion
- Heart Failure
- Weight Loss
- Poor Performance
- Depression
- Circling
- Incoordination
- Staggering Gait
- Difficult To Handle And Unpredictable
CHEMICAL CONTROL: Locoweed can be controlled by spraying actively growing or budding plants with clopyralid (20-30 gm ae/Ac), picloram (250 gm ai/Ac), and metsulfuron (30 gm ai/Ac). If plants are scattered, treatment of individual plants or patches may be practical.
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