In vivo evaluation of amitraz against ticks under field conditions in Ethiopia

An aqueous emulsion of amitraz (Bovitraz, Bayer AH), prepared and applied a ccording to the manufacturer's recommendations, was evaluated for its activ ity against cattle ticks on a dairy farm in Ethiopia. Eight crossbred heife r calves aged between 6 and 8 months and heavily infested with ticks were s elected and divided into equal treatment and control groups. The calves in the treatment group were hand-sprayed with the amitraz emulsion while the c ontrol group was left untreated. Each calf was restrained and ticks were co unted and identified in situ. One hundred percent tick control was achieved on Day 3 after acaricide application, and this was maintained for a furthe r 18 days. The residual effect was long, and protected the animals from re- infestation for 21 days. There was a significant difference between the mea n number of ticks on the control group compared to the treated group (P < 0 .05). An important finding in this trial was the rapid detachment of all ti ck instars from animals treated with the test acaricide.