An evaluation of two cypermethrin-based pour-on formulations on sheep infected with the biting louse, Bovicola ovis


Heath ACG, Nottingham RM, Bishop DM, Cole DJW
New Zealand Veterinary Journal, Volume 40, Issue 3, pp 104-106, Sep 1992
New Zealand Veterinary Journal, Volume 40, Issue 3, pp 104-106, Sep 1992
Article class: Scientific Article
Subject Terms: Agricultural compounds, Animal remedies/veterinary medicines, Disease/defect, Inflammation, Integument/skin/wool/hair/fur/feather, Parasites - external, Parasites - internal, Pest/pesticides, Treatment/therapy
Animal Type: Livestock, Production animal, Ruminant, Sheep
Publisher: Taylor and FrancisAbstract
Two synthetic pyrethroid (cypermethrin) based pour-on insecticide formulations, with high cis/trans isomer ratios (80:20) but differing in their respective active ingredient concentrations and solvent component(s), were applied to sheep infested with the biting-louse, Bovicola ovis. All treated sheep were penned with louse-infested sheep 9,12 and 15 weeks after the insecticide was applied. The 2% cypermethrin formulation achieved a higher level of control than the 1.25% cypermethrin formulation at each challenge interval when applied 12 weeks after shearing. The 2% cypermethrin formulation provided 97-100% control of lice from 4 to 16 weeks after application on sheep shorn 6 or 12 weeks prior to treatment. The 1.25% cypermethrin formulation provided 85% control of lice 4 weeks after application on sheep shorn 12 weeks prior to treatment, the level of control increasing to a maximum of 100% by week 9, and declining thereafter. The 2% cypermethrin formulation may provide a better level of control in long-woolled sheep than 1.25% cypermethrin, by compensating for the diluent effect of lipid.The whole of the literary matter of the New Zealand Veterinary Journal is copyright Taylor and Francis, Downloading this article signifies agreement with the terms and conditions of electronic access.