Comparative efficacy of several insecticides for control of cattle lice (Mallophaga: Trichodectidae and Anoplura: Haematopinidae)

Several insecticides were applied to cattle at various rates, mixtures, application methods and numbers of treatments and evaluated for control of cattle lice. The insecticides included permethrin at various rates as a pour-on with and without the synergist piperonyl butoxide (PBO), and also at various rates as a spray with and without PBO. Pirimiphos-methyl was evaluated as a pour-on at various rates and with one or two applications. Lambda cyhalothrin in microencapsulated formulation was compared to a non-microencapsulated formulation. Rabon ® was applied as a pour-on at two rates and at one or two treatments for each rate. Dimilin ® was applied as a pour-on at two rates and mixed with permethrin and applied at two rates. Five endectocides, Eprinex ®, Ivomec ®, Dectomax ®, Cydectin ® and Phoenectin ® were all applied at the same rate. The cattle utilized in this research were all infested with a mixture of lice species. The species included: Bovicola ( Damalinia) bovis (L.), Haematopinus eurysternus (Nitzsch), Linognthus vituli (L.) and Solenoptes capillatus (Enderlein). Most of the cattle were infested with at least two species and some had three or all four species present. All of the treatments except permethrin 1.0%+5% PBO, at a rate of 3 ml/45.4 kg wt. provided acceptable lice control with one application. Data indicated that applying the insecticides in early January should provide enough control to render the need for a second treatment unnecessary.