24 March 2000

Autumn return on for OPs but spring snags

By James Garner

ORGANOPHOSPHATE dips may be back on the market for autumn sheep dipping, but there is little chance that they will be available before this summer.

This means producers will have to consider alternative methods of ectoparasite control this spring because animal health companies have to change packaging of OP dips to meet government specifications, following MAFFs temporary withdrawal of OP products late last year.

However, two animal health companies – Bayticol and Novartis Animal Health – have since pulled out of the OP dip market. This, according to Bayticols technical services adviser Lisa Cox, is because the market for OP dips is too small and the cost of redesigning packaging too great.

But concerns that other animal health companies may follow suit and stop producing OP dips for these reasons are scotched by the National Office for Animal Healths director Roger Cook.

"Manufacturers are working diligently on proposals to meet government requirements on packaging," he says.

"Inevitably, theres a certain amount of caution from companies about what will be acceptable for government and what it will cost as sheep farmers dont have much money to spend at present."

Nevertheless, Mr Cook believes that a timetable for their re-introduction is almost in place. Proposals for new packaging will be put before the Veterinary Products Committee in May and should be accepted by mid-June, which should clear the way for OP products to be back on the market by autumn, he says.

Before then producers will be faced with blowfly, scab, lice and tick control problems and must make a choice from whats left on the market.

Producers want value for money and a product that will cover all ectoparasites in one treatment, says VLA entomologist Peter Bates, who highlights problems hill farmers potentially face when they have to make more than one gather.

Alarm that these cover-all products are now not available because of OP withdrawal is dismissed by Mr Bates, who says there are synthetic pyreithroid products available that can do this but producers need to read the instructions to ensure they are used properly.

"All SP dips will cure scab and kill chewing lice when instructions are followed. Some formulations containing high cis cypermethrin – HCC – and flumethrin will protect against scab and prevent tick attack." However, he warns that some of these will need two dips to give scab cover and that flumethrin does not prevent blowfly strike.

Best use

This point is reinforced by NSA chief executive John Thorley, who says producers must make the best use of the products which are left and read and understand the label.

Despite this advice, Mr Thorley would like to see a broad range of products available. "We feel that at least once a year, for welfare and economic reasons, flockmasters should treat sheep with a broad spectrum product."

Other products such as pour-ons and injectables have their place, but only cover a narrow band of ectoparasites, which producers should be aware of, he says.

Other problems do exist with SPs, says Mr Thorley, such as dip disposal and resistance. However, both men believe resistance claims have been overplayed, with only a handful of cases confirmed.

Following manufacturers instructions could help prevent resistance becoming more widespread, says Mr Bates. He also suggests that flock owners ensure vets diagnose ectoparasites before treating, if they want to save money.

"It may cost £50-£60 to have this done, but it is best way of preventing you wasting money treating scab when your sheep have lice," he adds.

OPALTERNATIVES

&#8226 Choose an alternative.

&#8226 Read label carefully.

&#8226 Seek vet diagnosis.