Locoweed Poisoning of Horses

programs. INTRODUCTION Locoweed has been reported to be the most widespread poisonous plant problem in the Western United States. It has a substantial economic impact, and may be responsible for the loss of more than $300 million in annual income due to deaths of poisoned livestock. The major contributors to these poisonings are plants from the Astragalus (Figure 1) and Oxytropis (Figure 2) genera, which are commonly referred to as locoweed or milkvetch. Since there are over 300 species of these plants found across the United States, this publication will not discuss the identification, distribution, or habitat of locoweeds; readers should refer to Circular 557, A Guide to the Common Locoweeds and Milkvetches of New Mexico (http://aces.nmsu.edu/pubs/_circulars/CR-557. pdf ), for such information. Instead, this guide will focus on the toxicity found in horses.