The efficacy of fenbendazole and albendazole against the lungworm Muellerius capillaris in goats.

In five trials it was found that the daily administration of fenbendazole in the food for 1 or 2 weeks at dosages of 1.25, 2.5 or 5 mg kg-1 live weight was highly effective against Muellerius capillaris infection in goats. Treated animals had significantly lower numbers of larvae in the faeces for up to 223 days after treatment. There was no obvious difference between the different dose levels. Daily treatment for 2 weeks seemed to be slightly more effective than treatment for 1 week. Treatment for 1 week twice with an intervening period of 1 week seemed to be more effective than treatment for 2 weeks continuously. Goats given a single treatment with fenbendazole at 25 mg kg-1 had a significantly lower number of M. capillaris larvae in their faeces on Days 34 and 69 after treatment than the controls, but on Days 126 and 156 after treatment there was no significant difference between these two groups. Albendazole given daily for 2 weeks at a dose of 1.0 mg kg-1 showed a significant effect for up to 153 days after treatment, which was similar to the result of daily treatment with 1.25 mg kg-1 fenbendazole. Goats treated with albendazole twice at 10 mg kg-1 with a 1 week interval showed a significant reduction in the number of Muellerius larvae in the faeces on Day 41 after treatment, but not on Days 97 and 153 after treatment.(ABSTRACT TRUNCATED AT 250 WORDS)