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United States Department of Agriculture

Agricultural Research Service



2010 Annual Report

1a. Objectives (from AD-416)
The objectives of this cooperative research project are to: 1) determine fecal egg count when goats and sheep graze bio-active forage plants or are offered bio-active plant materials; 2) determine the impact of phytochemicals on Haemonchus contortus infections in goats and sheep; and 3) determine anthelmintic potential of extracts from herbaceous and woody plants using a Caenorhabditis elegans in vitro assay and an adult Haemonchus/gerbil in vivo assay.

1b. Approach (from AD-416)
Laboratory experiments and pen and pasture studies with small ruminants will be conducted with forage plants, plant extracts, and isolated chemicals that have anthelmintic properties. Specifically, a laboratory assay using C. elegans will be established and used to identify plants with anthelmintic potential. An in vivo gerbil assay will be used to evaluate anthelmintic effects of plant materials on adult H. contortus worms. H. contortus control in meat goats and sheep will be measured by evaluating effects of plant materials on H. contortus egg production and worm burdens in pen-fed and grazing animals. Information obtained will enhance existing research-based management guidelines related to gastrointestinal parasite control in goats and sheep.

3. Progress Report
The first year of a study to evaluate Haemonchus contortus egg numbers and larval differentiation in feces when meat goats were finished on bioactive pastures of red clover, birdsfoot trefoil, and chicory have been completed. The second year of the study was initiated 21 May 2010. Collaborative studies with the Virginia-Maryland College of Veterinary Medicine at Virginia Tech confirmed that an orange oil emulsion administered to H. contortus-infected sheep effectively reduces fecal worm egg numbers and the worm burden in the animals. Investigation of anthelmintic effects of sesquiterpene lactone-enriched extracts from chicory herbage is being investigated with a gerbil model system. Collaborative studies with plant extracts, and other products using gerbils artificially infected with Haemonchus contortus were completed. The information demonstrated the pros and cons of the gerbil system as an in vivo screening system and presented methodology that can be used to deliver and test plant extracts and natural compounds in gerbils by the oral route with no toxicity to the animals. In addition, a screening method using Caenohabditis elegans as a model system to screen tannin-rich and medicinal plant extracts for their potential anthelmintic properties has been initiated. This project will enhance existing research-based management guidelines related to pasture and gastrointestinal parasite control in goats and sheep, information useful to small farm producers. The ADODR communicated regularly via e-mail, telephone, and site visits with PI in order to coordinate sample analyses and information exchange/updates. The ADODR provides guidance to PI on required project reports and budget reporting.

4. Accomplishments

Last Modified: 06/23/2017
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