Effects of distribution of quebracho extracts on experimental Haemonchus contortus infections in goats

Summary

The effects of tannins on adult populations of Haemonchus contortus, Trichostrongylus colubriformis and Teladorsagia circumcincta
in goats are characterised mainly by a decrease in egg excretion without any significant changes in worm number. In contrast,
the impact of tannins on T. colubriformis or T. circumcincta third-stage larvae (L3) is associated with a significant reduction in worm
establishment. The objective of the present study was to examine the effects of quebracho extract tannins on H. contortus L3. The
consequences of consumption of sainfoin hay were also examined.
Twenty-one naı¨ve kids were divided into three experimental groups. Group Q received quebracho extract and group S received
sainfoin hay from days D3 to D5. Group C remained as an infected control group. All kids received 1500 L3 H. contortus on D0, D1
and D2. On D18, post-infection, the kids were slaughtered and the worm populations compared in the different groups. Compared
to the control values, the worm counts decreased, respectively, by 33% and 38% in groups Q and S but the differences were not significant.
No differences were found in pathophysiological measurements between the three groups. The results confirm differences in
tannin effect according to nematode species but not parasitic stage.