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United States Department of Agriculture

Agricultural Research Service


Location: Poisonous Plant Research

2011 Annual Report

1a. Objectives (from AD-416)
The objectives of this research are to: 1) Evaluate and determine the adverse effects of locoweed on cattle production in New Mexico; 2) Evaluate and develop new tools for diagnostics; 3) Determine the role of a newly identified endophyte (Undifilum) in swainsonine production and locoweed growth and longevity; 4) Better understand the rangeland ecology where locoweeds dominate and evaluate methods of control (biological and chemical); and 5) Develop integrated management approaches to improve utilization of rangelands where locoweed grows.

1b. Approach (from AD-416)
This is a coordinated research approach between the USDA-ARS-Poisonous Plant Research Lab, Logan, UT and the Rangeland Research Group and College of Agriculture and Home Economics at New Mexico State University in Las Cruces, NM. The proposed joint research will include methods to: 1) better understand the ecology of locoweeds in this region which includes the Southern High Plains and Canadian Pecos Valleys of West Texas and eastern New Mexico; 2) understand more fully the biological characteristics of the locoweeds which includes the role of a newly discovered endophyte (Undifilum) in toxin (swainsonine) production within the plant and plant hardiness; 3) develop sound methods to understand the biology of the endophyte and employ molecular tools to determine if it can be supressed; 4) reduce the toxic effects in cattle and improve rangeland utilization through grazing strategies; 5) better evaluate locoweed's effects on early reproduction in cow calf operations; 6) identify biomarkers for improved diagnostics and prognosis of locoweed poisoning; and 7) develop a holistic management program to reduce livestock losses and improve the economic stability in this region.

3. Progress Report
Effects of locoweed on cattle production in north eastern New Mexico and south eastern Colorado. Surveys in southeastern Colorado and northeastern New Mexico indicate that locoweed populations are declining because of severe drought conditions. The toxicity of locoweed has been linked to infestation by the endophyte, Undifilum. The relationship between the endophyte, Undifilium oxytropis, and locoweeds is being investigated and in all toxic Astragalus and Oxytropis species swainsonine is only present if the endophyte is present, thus explaining why some populations are toxic while others are not. While the benefit of the endophyte to the plant is not understood, studies are ongoing to determine what effect different levels of precipitation, nitrogen and atmospheric CO2 may have on endophyte infection and subsequent swainsonine production in the plants. Growth and spore characteristics of endophyte isolates were completed. Research on effects of protein supplementation, commercial feed additives and manipulation of rumen microflora in sheep to mitigate locoweed poisoning was investigated and data is currently being evaluated. ADODR monitoring is done via phone calls, e-mail, and site visits.

4. Accomplishments

Last Modified: 06/26/2017
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