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 microplus) and the performance of commercial cattle treated with the macrocylic lactone endectocide, moxidectin, formulated either as an injection or as a pour-on.

DESIGN

Groups of 10-12 tick infested cattle were treated with moxidectin injection, moxidectin pour-on or remained untreated (28-day trials) or were treated with deltamethrin-ethion as a dip (140-day trials). The cattle were exposed to natural tick challenge under field conditions.

PROCEDURE

Tick numbers on trial cattle were recorded 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 weights 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 counts 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 at each inspection with the exception of the pour-on treatment at week 8 in one trial and week 9 in the other trial. Additional weight gain was recorded for 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 systemic adverse reaction in any treated cattle in any trial.

CONCLUSION

Good to excellent control of the cattle tick (Boophilus microplus) was demonstrated with the moxidectin formulations in all trials, the injection being particularly effective. An improved performance was recorded in all trials in cattle treated with both moxidectin formulations when compared with the untreated cattle and with cattle treated with the deltamethrin-ethion dip. There was no evidence of any local or systemic adverse reaction to treatment with either moxidectin formulation.