Efficacy of eprinomectin against mange mites in cattle

To determine whether eprinomectin was effective against mange caused by Chorioptes bovis and Sarcoptes bovis in cattle.

80 cows naturally infested with C bovis and 30 cattle experimentally infested with S bovis.

6 trials were performed to determine efficacy against C bovis, and 2 trials were performed to determine efficacy against S bovis. In each trial, a group of untreated animals or of animals treated with vehicle alone was compared with a group of animals treated with a 0.5% formulation of eprinomectin applied topically (500 micrograms/kg). Number of mites in skin scrapings was determined prior to treatment and at weekly intervals for 8 weeks after treatment. Severity of skin lesions was evaluated when skin scrapings were obtained. In 5 trials, animals were weighed before and 56 days after treatment.

Mite counts for treated cattle were significantly less than counts for control cattle from day 14 onwards in trials to determine efficacy against C bovis and from day 7 onwards in trials to determine efficacy against S bovis. Mites were not detected in scrapings collected from treated cattle on day 56. Mean weight gain of treated cattle was not significantly different from mean weight gain of control cattle in trials evaluating efficacy against C bovis but was significantly greater in trials evaluating efficacy against S bovis.

Eprinomectin was highly effective against C bovis and S bovis. Because eprinomectin can be administered to lactating cows, it may be useful for controlling mange in cattle.