Milkvetch is the common name for plants in the Astralagus genus of plants, which is part of the larger Fabaceae family, or the legume family.
In an area where livestock grazing is a foundational element to the way of life for many, these deadly beauties pose a real threat. These eye-catching, predominantly native plants can contain a neurotoxin called swainsonine. However, there are many species of milkvetch, and not all of them contain swainsonine, so proper identification is key to knowing if you have a toxic plant on your land or not. The ones containing swainsonine are commonly referred to as locoweed.
Grazing on these plants can cause locoism, “loco” being the Spanish word for crazy, an apt term that refers to the neurological effects caused by consuming swainsonine.
The symptoms of locoism include depression, circling, lack of coordination, staggering gait and unpredictable, unusual behavior. The toxin can also cause infertility, weight loss, growth disruption, heart failure, reproduction failure and potentially contribute to birth defects. Animals that eat locoweed become addicted to it, creating a vicious cycle of symptoms and consumption.
Removing the animals from the infested area can help them recover, but the damage can be permanent, and there are no known effective treatments.
Other species of milkvetch do not contain swainsonine, but instead can accumulate toxic levels of the mineral selenium. There are two types of selenium poisoning: acute and chronic. Acute poisoning happens when animals ingest high levels of selenium in a short period of time. Characteristic symptoms in cattle, horses and swine consist of abnormal posture, unsteady gait, diarrhea, abdominal pain, increased respiration and pulse, prostration, and death.
Chronic poisoning due to long-term consumption manifests as an alkali disease, known as the “blind staggers.” Animals with the blind staggers show signs of decreased vitality, emaciation, rough hair coat, loss of hair, overgrown hooves, decreased eyesight and lameness. As the disease progresses to its terminal stages, the animal loses eyesight entirely, respiration becomes labored, and they experience paralysis of tongue and the swallowing process. Death soon follows.
Removing the animals from the area they are grazing locoweed and feeding them a low-selenium, high-quality diet can help ease symptoms; however, like locoism, there is no known totally effective cure for the blind staggers.
The economic toll of locoism can be severe. According to New Mexico State University, it is estimated that locoism causes an annual loss of $300 million in the western United States.
They are the most widespread group of poisonous plants across the West, and with more than 300 unique species, identification can be tricky at best. If you suspect that you may have locoweed on your land, contact the Archuleta County Weed and Pest Department, the Colorado State University (CSU) Extension Office or the San Juan Conservation District to get a positive identification.
Archuleta County Weed and Pest is your local resource for managing noxious weed populations and controlling other pests.
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Seed potatoes for sale
Place your order today for Colorado certified and non-GMO seed potatoes. Five varieties of potatoes are available. Visit https://archuleta.extension.colostate.edu or call (970) 264-5931 to learn more and place your order today. Pickup is next week.
Field to Freezer Course
Colorado Parks and Wildlife will be holding its Field to Freezer Course on May 16 and 17 at the CSU Extension building located at 344 U.S. 84.
Trained professionals will teach you how to responsibly care for and process the meat from any big game ungulate in Colorado. Participants must be at least 16 years old. Visit https://forms.gle/owfhB5R8PTpYYHGGA to register.
There are limited spots available. Applications are due by May 9.
Vermiculture workshop
Join Galabota for a fun, hands-on and engaging Vermiculture Workshop. Learn all about the vital role worms play in healthy soils and build your own worm composting bin.
It is set for 10 a.m. on June 28 at the CSU Extension Building at 344 U.S. 84. There is a $20 materials fee. RSVP at (970) 264-5931 or https://archuleta.extension.colostate.edu/.
