12 April 1996


Profit from livestock enterprises depends on freedom from disease. Without that, performance will be depressed and animal welfare at risk.

Internal and external parasites of cattle, sheep and pigs are big contributors to poor thrift, leading to depressed performance and death in extreme cases. These losses can be reduce and prevented by a wide range of proven products now on the market.

This supplement reviews the products available and their correct use, from those with highly specific action to others with broad spectrum activity.

All approved and proven parasiticides can make a useful contribution to stock health. But only when used correctly. It makes good sense to read the makers instructions carefully before treating stock, or, better still, buying the product.

Take sheep scab, for example. The label should state whether the product is effective against scab and whether it protects against reinfestation. As well as the active ingredient, much depends on fleece length. Failure to treat as instructed can cause incomplete scab control and encourage resistant scab mites to develop. As our supplement explains there have already been two cases of scab resistance to flumethrin in the UK.

Persistent use of any one treatment risks parasite resistance to that specific drug sooner or later.

The use of wormer products, preferably on an annual rotation basis, and alongside clean field techniques where permitted, will ensure their continued efficacy against a wide range of gut nematodes.

For best results stock must be dosed according to weight. Correct calibration and maintenance of drenching/dosing equipment is also vital. It will pay to seek vet advice.

This is especially true when devising a programme to control lungworm in cattle. An effective strategy can be achieved during most of the grazing season by use of long-acting wormers. But in some instances it will also pay to vaccinate stock to ensure calves develop natural immunity. This will offer protection against lungworm in future grazing seasons.

When scab is confirmed the whole flock and not just the affected sheep or group must be treated. Advice on pS16.