Comparative efficacy of six anthelmintics for the control of gastrointestinal nematodes in sheep in Matanzas, Cuba

The efficacy of injectable levamisol, a mixture of levamisol and niclosamide, oral ivermectin, injectable ivermectin, oral albendazole and albendazole sulphoxide was evaluated in two farms with the dose recommended by the manufacturer. In the LABIOFAM farm 72 commercial sheep (uncontrolled crossbred Suffolk and Pelibuey) and in the Dos Mercedes farm 77 pure Pelibuey sheep were used. The selection of the animals was made according to their weight and an initial faecal egg count (FEC) superior to 100 eggs per gram (EPG). Animals were randomly divided into seven groups: LV (injectable levamisol), NC (tetramisol and niclosamida), LB (injectable ivermectin), IO (oral ivermectin), AZ (albendazol), LZ (albendazole sulphoxide) and C untreated control group. The FEC was carried out 14 and 4 days before, and the day of, drenching to assess the level of parasitic infection. A faecal egg count reduction test (FECRT) was performed at the 11th day to all groups. Three days after drenching two animals per group were slaughtered to determine the worm burden in each group. The results obtained showed evidences of Haemonchus spp. in LABIOFAM and Trichostrongylus spp. in Dos Mercedes for LV and NC, respectively. These results were reinforced with the predominance of each genus when helminthological necropsies were carried out. The efficacy of the other products (LB, LZ, AZ and IO) did not differ among them at the 11th day after drenching. These results indicate that the imidazotiazole group has showed a low level of anthelmintic resistance reached a questionable efficacy, but the rest of the products seem to be effective against gastrointestinal parasitism in sheep. © 2003 Elsevier B.V. All rights reserved