Efficacy of albendazole, levamisole and fenbendazole against gastrointestinal nematodes of cattle, with emphasis on inhibited early fourth stage Ostertagia ostertagi larvae

摘要: Abstract An experiment was conducted to compare the anthelmintic efficacy of albendazole (ABZ), levamisole (LEV) and fenbendazole (FBZ) against inhibited early fourth stage larvae (EL4) Ostertagia ostertagi during April in Louisiana. Forty cross-bred beef heifers (average weight 165 kg) were acquired winter grazed on pastures contaminated with O. other nematodes until April. The cattle weighed randomly allotted into four groups ten animals 6 treatments administered 7 Experimental groupings were: Group 1, non-treated controls; 2, ABZ by oral drench at 10 mg kg−1; 3, LEV topical, pour-on administration back midline 4, FBZ kg−. Equal numbers from each group slaughtered daily between 13 days after treatment. Mean developmental stages present untreated controls adults, 714; developing L4 (DL4), 6487; EL4, 21 719. mean percentage EL4 51.8. Smaller Haemonchus placei, Trichostrongylus axei Cooperia spp. recovered uniformly control cattle. Percentage reduction values for three compounds DL4 respectively, ABZ, 99.0, 95.3, 84.9; LEV, 1.0, 21.8, 32.1; FBZ, 99.2, 97.2, 97.5. Differences counts not significant, but all cases worm FBZ-treated significantly lower (P ≤ 0.05) than LEV-treated Both 98–100% effective adults L4, T. L4. 100% 85.6% axei, 94.6% 89.59% respectively.