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Condensed Tannins: Potential as a Tool for Controlling Parasitic Worms in Small Ruminants

Condensed Tannins: Potential as a Tool for Controlling Parasitic Worms in Small Ruminants. Thomas Terrill Fort Valley State University Fort Valley, GA. CONTROL MEASURES. Traditional Anthelmintics Management Novel Vaccines Resistance/Tolerance Condensed tannins Nematode-trapping fungi.

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Condensed Tannins: Potential as a Tool for Controlling Parasitic Worms in Small Ruminants

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  1. Condensed Tannins: Potential as a Tool for Controlling Parasitic Worms in Small Ruminants Thomas Terrill Fort Valley State University Fort Valley, GA

  2. CONTROL MEASURES • Traditional • Anthelmintics • Management • Novel • Vaccines • Resistance/Tolerance • Condensed tannins • Nematode-trapping fungi

  3. CONDENSED TANNINS (CT) • CT-containing forages • Sericea lespedeza • Birdsfoot trefoil • Big trefoil • Sainfoin • Leucaena • Purified CT • Quebracho

  4. CONDENSED TANNINS IN FORAGES • Vary in concentration • Alfalfa (none) • Birdsfoot trefoil (2-3 %) • Big trefoil (4-5 %) • Sericea lespedeza (6-7 %) • Canary clover (14%) • Vary in reactivity • Birdsfoot trefoil CT (low reactivity) • Sericea lespedeza CT (high reactivity)

  5. CONDENSED TANNINS IN RUMINANT DIETS • Plant CT - occur in ‘free’ and ‘bound’ forms • CT binds to protein at neutral pH (rumen) • CT disassociates from protein under acid conditions (abomasum) • CT not absorbed from the GIT

  6. CONDENSED TANNINS • Can have positive and negative effects on the nutrition and health of ruminant animals through influence on utilization of nutrients • Concentration and reactivity of CT are important considerations

  7. BENEFICAL EFFECTS OF CONDENSED TANNINS • Increased net absorption of EAAs • Increased wool growth and growth rate • Increased liveweight gain • Higher ovulation rate • Higher milk yield • Reduced bloat • Reduced detrimental effects of internal parasites

  8. DETRIMENTAL EFFECTS OF CONDENSED TANNINS • Reduced dry matter intake • Decreased fiber digestibility • Reduced wool growth • Reduced digestion of amino acids in SI • Reduced N and S digestion

  9. RESEARCH ON ANTHELMINTIC EFFECTS OF CONDENSED TANNINS • In vitro experiments with purified CT • Grazing trials/feeding trials with CT-containing forages • Feeding trials with purified CT

  10. IN VITRO EXPERIMENTS WITH PURIFIED CT • CT extracted from various forages, purified • Birdsfoot trefoil • Big trefoil • Sulla • Sainfoin • Dock • Quebracho

  11. IN VITRO EXPERIMENTS WITH PURIFIED CT • Tested effects on development/viability of parasite larvae • Haemonchus contortus • Trichostrongylus colubriformis • Teladorsagia circumcincta • Effects on egg hatching • T. colubriformis

  12. RESULTS • CT from all of the different forages greatly reduced hatching of T. colubriformis eggs • 4 % CT, no viable eggs • 2 % CT, small number of eggs developed (2-11%) for some CT types • Development of T. colubriformis larvae from L1 to L3 stage • 4 % CT, 3 to 8 % of larvae developed • 2 % CT, 4 to 18 % of larvae developed

  13. RESULTS (Cont.) • Quebracho CT reduced viability of L3 larvae from H. contortus, T. circumcincta and T. colubriformis

  14. ANTHELMINTIC EFFECTS OF CT-CONTAINING FORAGES: SULLA • Grazing trials • Increased growth of parasitized lambs compared to non-CT forage (afalfa) • Reduced egg counts • Reduced worm burdens • Feeding trials • Increased liveweight gain in deer • Reduced number of abomasal nematodes • Increased immune response in lambs

  15. ANTHELMINTIC EFFECTS OF CT-CONTAINING FORAGES: SERICEA LESPEDEZA • Grazing trial comparing sericea lespedeza and rye/crabgrass pasture for goats • Goats naturally infected, mostly H. contortus • Lower FEC and total egg output for goats grazing lespedeza • 88 % less development from egg stage to L3 larvae in feces from lespedeza goats

  16. ANTHELMINTIC EFFECTS OF PURIFIED CT • Feeding trials with quebracho CT • Sheep artificially infected with either H. contortus, T. circumcincta or T. colubriformis • Fed quebracho CT extract at 4, 8, and 16% of intake • Reduced FEC from intestinal worms with increasing level of CT in the diet • Intestinal worm burden lowest in sheep fed CT at 8 % of intake • No effect on FEC or worm burden from sheep infected with abomasal worms

  17. ANTHELMINTIC EFFECTS OF CT: SUMMARY • Indirect effects • Increased rumen by-pass protein • Increased AA absorption to overcome effects of parasitism • Improved immune function • Direct effects • Toxic to parasite adult worms or larvae • Reduced egg viability in feces

  18. CONCLUSIONS • Condensed tannins in forages or in pure form have potential to reduce effects of parasitism in small ruminants • Further research is needed to evaluate CT as a component of an integrated parasite control program for goats and sheep

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