2011 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.
The second year of a study to enumerate fecal parasite egg numbers and barberpole worm larval differentiation in feces when meat goats were finished on bioactive pastures of red clover, birdsfoot trefoil, and chicory have been completed. The third year of the study was initiated 24 May 2011.
Potential differential effects of chicory sesquiterpene lactones on fourth stage larvae of Haemonchus contortus are being investigated in the laboratory using lactucin- or 8-deoxylactucin-enriched extracts prepared from leaves of the forage chicory cultivars ‘Forage Feast’ and ‘Oasis’, respectively, and larvae isolated from gerbils artificially infected with third stage larvae. A manuscript describing reductions in the worm burden and the number of fecal worm eggs in H. contortus-infected sheep in response to administration of an orange terpene oil emulsion is in preparation.
The Caenorhabditis elegans system and the gerbil-model system for Haemonchus evaluation are currently being maintained by the collaborator at Virginia Tech. Collaboration in writing/publishing three manuscripts on potential anthelmintic plants/extracts evaluated by the two systems on the research is currently being finalized.
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.