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United States Department of Agriculture

Agricultural Research Service


Location: Poisonous Plant Research

2010 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 Cruses, 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
The use of protein supplements to reduce voluntary intake of wooly locoweed was evaluated and data collected in prior grazing seasons is being analyzed and compiled. Preliminary feeding trials using commercial feed additives suggest that these feed additives could alleviate the detrimental metabolic effects of locoweed. The use of intermittent targeted grazing with sheep to reduce white locoweed density has been completed and the plant and animal data has been partially analyzed. A controlled pen study was done using fecal fluorometry analysis to determine amounts of locoweed in sheep diets. Early results from laboratory trials conducted with rumen fluid from sheep fed white and purple locoweed indicated that rumen fermentation and the chemotactic responses of rumen bacteria were unaffected. In preparation for defining new species of Undifilum, RAPDs and completed sequencing for two regions of the DNA of Undifilum endophyte isolates were done. Growth and spore characteristics of the different endophyte isolates were also completed. Work on quantifying swainsonine in plant samples using UPLC-MS analysis is continuing. Determining the relationship between the fungus and its host and evaluating the effects of water depravation and soil nitrogen levels on subsequent swainsonine production continues. Potential biological control of locoweed in Union Co. NM using Four-lined locoweevil is continuing. However, due to drought, the locoweed populations we are studying, both in Colorado and New Mexico have all but disappeared. Despite exhaustive surveys in both Colorado and northern New Mexico, no new weevils were found in either location. Interaction is exchanged via e-mail, plus conversations, on-site visits, meetings, web site access, FedEx and U.S. postal service.

4. Accomplishments

Last Modified: 10/16/2017
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