Non-specific resistance of sheep against Haemonchus contortus with Freund's complete adjuvant

Six groups of four ovines each were injected intraperitoneally with Freund's complete adjuvant (FCA), at various times before, during, or after infection with 10 000 larvae (L3) of Haemonchus contortus per sheep. Animals in groups A and B received FCA on days 14 and 7, respectively, before infection. Ovines in group C were treated with FCA on the same day of infection; while sheep in groups D, E, and F were injected with the adjuvant on days 7, 14, and 21, respectively, after infection. Significant reductions in adult worm numbers compared with non-treated controls, as determined 42 days after infection, were of 30%, 34%, 45%, 52%, 56%, and 55% in groups A, B, C, D, E, and F, respectively. A significant correlation, between the time of FCA administration (referred to the day of infection) and the number of worms recovered at necropsy, was also observed.