Cypermethrin pour-on for control of the sheep body louse (Damalinia ovis)

The sheep body louse Damalinia ovis is a potentially serious problem affecting the value of the fleece and possibly causing reduced weight gains. Control has been based on the dipping or showering of sheep using insecticidal oil in water emulsions. The results using a pour-on formulation of the synthetic pyrethroid cypermethrin to control louse infestation are reported. Application rates of 5 mg/kg or more gave 99 to 100 per cent control.