2013 Annual Report
1a.Objectives (from AD-416):
Survey grasslands of Mongolia and the western United States for species of Oxytropis, Astragalus and Swainsonia to determine which species and populations contain the toxic alkaloid swainsonine that causes locoweed poisoning in livestock.
1b.Approach (from AD-416):
The USDA/ARS Poisonous Plant Lab (PPRL) has developed chemical assays for the toxic alkaloid swainsonine and for detecting and quantifying the endophytic fungus Undifilum which produces swainsonine. Species of Oxytropis, Astragalus and Swainsona will be collected throughout Mongolia and the western United States and small samples of leaf and flower material will be sent to PPRL to determine the presence of the endophyte and concentration of swainsonine. From these samples toxicity of the species will be determined.
Poisoning in livestock from plants containing swainsonine (the locoweed toxin) is a worldwide problem and is particularly significant on the vast grasslands of Inner Mongolia in China where Oxytropis glabra infests over 300 million hectares. Continued invasion of this locoweed on the grasslands of China decreases animal production thus causing hardship on herders and their families that are reliant on the grasslands for their subsistence. ARS Scientists continue to collaborate with scientists from Inner Mongolia to understand the endophyte/plant relationship and are developing methods to control locoweeds, inhibit the endophyte and improve the rangelands to mitigate livestock losses. Species of Astragalus and Oxytropis are highly nutritious. Therefore, fungicide treatments are being investigated as a potential way to control the endophytes and provide endophyte free plants. It was determined that the endophyte is transferred vertically through the seed and if the endophyte free plants can be established a population shift to endophyte free plants would be a huge benefit to livestock producers in this region.