THE APPLICATION OF MOXIDECTIN FORMULATIONS FOR CONTROL OF THE CATTLE TICK (BOOPHILUS-MICROPLUS) UNDER QUEENSLAND FIELD CONDITIONS

Objective To assess the control of the cattle tick (Boophilus microplu s) and the performance of commercial cattle treated with the macrocyli c lactone endectocide, moxidectin, formulated either as an injection o r as a pour-on. Design Groups of 10-12 tick infested cattle were treat ed with moxidectin injection, moxidectin pour-on or remained untreated (28-day trials) or were treated with deltamethrin-ethion as a dip (14 0-day trials). The cattle were exposed to natural tick challenge under field conditions. Procedure Tick numbers on trial cattle were recorde d in each trial before the initial treatment and in the 28-day trials at 7, 14, 21 and 28 days or in the 140-day trials, at 28-day intervals before each of the treatments and at the final inspection. Body weigh ts of the cattle were also recorded prior to the initial treatment and at the termination of each trial. Cattle were observed on the day of each treatment and at each inspection for evidence of any reactions to treatment. Results 28-day trials: Significant reductions in tick coun ts were recorded in both treatment groups when compared with cattle in the untreated group, Weight advantage was recorded in the moxidectin treated groups. 140-day trials: All three treatments resulted in zero or low tick counts al each inspection with the exception of the pour-o n treatment at week 8 in one trial and week 9 in the other trial. Addi tional weight gain was recorded far both the moxidectin treated groups , relative to the deltamethrin-ethion dip groups, but was significant only for the pour-on groups. There was no evidence of any local or sys temic adverse reaction in any treated cattle in any trial. Conclusion Good to excellent control of the cattle tick (Boophilus micropius) was demonstrated with the moxidectin formulations in all trials, the inje ction being particularly effective. An improved performance was record ed in all trials in cattle treated with both moxidectin formulations w hen compared with the untreated cattle and with cattle treated with th e deltamethrin-ethion dip. There was no evidence of any local or syste mic adverse reaction to treatment with either moxidectin formulation.