Barrier Livestock Louse Powder is a potent, yet gentle, 100% natural insect repellent, specially designed for use against bloodsucking and biting lice. Fully suitable for use in organic farming, the easy to use powder can be applied directly and provides up to six weeks protection (weather conditions dependent). Note: Potency will be affected if used in conjunction with chemical based products. HSE 8712. This HSE approved and 100% natural insect repellent is perfect for using against blood sucking and biting lice. Use by direct application to a wide range of animals including ponies, horses, donkeys, cattle, goats, rabbits and small pets. It does not taint eggs.