Efficacy of topically administered ivermectin against chorioptic and sarcoptic mange of cattle.

The efficacy of topically administered ivermectin against Chorioptes bovis and Sarcoptes scabiei var bovis on cattle was evaluated in five studies involving a total of 68 cattle. Treatment with ivermectin solution at a dose rate of 500 micrograms/kg bodyweight topically once was fully effective against C bovis and S scabiei when applied to healthy skin. Efficacy against S scabiei was impaired when the formulation was applied over areas of severe lesions caused by this parasite, presumably due to reduced absorption of ivermectin.