Effect of a condensed tannin containing forage (sericea lespedeza), fed as pellets, on natural and experimental challenge nematode infection in lambs

Effect of a condensed tannin containing forage (sericea lespedeza), fed as pellets, on natural and experimental challenge nematode infection in lambs

Summary

The first of 2 studies, under this grant, was completed. This study evaluated the effect of feeding sericea lespedeza (SL) meal free choice on H. contortus infection in lambs maintained in confinement. The original protocol was to use SL in a pellet formulation, but it was difficult to find a feed company that would pellet SL; therefore, a meal formulation of SL was used. SL was fed to lambs with existing and establishing infections. Fecal egg count and number of worms were reduced more so in existing infection lambs than establishing infection lambs. The second study to evaluate feeding SL as a supplement to grazing lambs will be conducted during the summer, 2006. We now have a pellet formulation of SL which will be used.

Objectives/Performance Targets

The objective of the grant is to determine the effect of sericea lespedeza (a forage plant high in condensed tannins) on Haemonchus contortus infection in lambs. The objective of this first study was to determine this effect using a meal formulation fed free choice to lambs in confinement.

Accomplishments/Milestones

Twenty-eight mixed sex lambs with essentially zero fecal egg count (FEC) were randomly allocated to 4 treatment groups of 7 animals each. Lambs were kept in cement floored pens. Two groups received a bolus of 5000 Haemonchus contortus infective larvae (L3) once (existing infection). The remaining 2 groups received trickle infections of 500 H. contortus L3 3 times a week for 3 weeks (establishing infection). Sericea lespedeza (SL) meal was fed over a 5 week period to one of the existing and establishing infection groups while the other groups were fed bermudagrass hay (control). All groups were fed bermudagrass hay for an additional 2 weeks at which time all animals were necropsied. FEC was significantly reduced in the existing infection SL fed group and was lower in the establishing infection SL fed group, but that difference was not significant. After SL feeding was terminated, FEC increased in both existing and establishing infection groups which indicated an effect on female worm fecundity. At necropsy, there were fewer worms in both SL fed groups, but the differences were not significant.

Impacts and Contributions/Outcomes

Sericea lespedeza, fed as a meal, has the potential to help control Haemonchus contortus infection in lambs.

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