Abstract:
Two doses of infective larvae of 20 000 Trichostrongylus axei, dosed to Merino lambs at an interval of 14 days and subsequently challenged with Ostertagia circumcincta, caused a significant reduction (P < 0,01) in the establishment of 5th and adult stages of the latter. T. axei was unable to protect Merino sheep against homologous challenge nor was Haemonchus contortus a successful vaccine against challenge with the same species. The vaccinated group showed a reduction (P < 0,025) only in 5th and adult H. contortus, but not in the total worm burdens.
