Efficacy of an albendazole slow-release capsule for the control of susceptible or resistant nematode parasites of dairy goats

The efficacy of albendazole slow release capsules-ASRC- (Proftril-Captec) on gastro-intestinal nematodes of dairy-goats was assessed both for benzimidazole (BZ) susceptible and resistant strains. For BZ susceptible strains, the efficacy of ASRC, assessed by controlled test, ranged from 92% for Trichostrongylus colubriformis to more than 99% for Haemonchus contortus on existing worm burdens, The administration of the ASRC prevented infection with the same strains for 85 to 91 days post treatment, In a dairy goat farm, where both in vitro and in vivo tests indicated a high level of BZ resistance, the efficacy of ASRC on present infections, assessed by Faecal Egg Count Reduction test, ranged from 20 to 60% according to the sampling date (13 to 88 days post treatment), On the same farm the ASRC given at turnout to non infected (primiparous) goats prevented egg shedding up to 72 days (30 for controls), In contrast the ASRC given to infected (multiparous) goats did not prevent egg shedding. The present results show that the ASRC is an efficient device for controlling BZ susceptible nematodes. The ASRC prevents infection with BZ resistant larvae whereas existing infections are not reduced.