31 March 2000

OP GAP A BIG HEADACHE

Which products should you use to control endo and ecto parasites this year? p4

Controlling scab and other sheep ectoparasites without OP dips p17

Vaccines offer promise for scab and worm control p18

How to cope with husk in cattle p18

Fluke risk increases with wet winters p19

Edited by Emma Penny

Controlling parasites has never been straightforward. The weather, animal movements, resistance concerns and economics all play a part in the decisions taken on-farm.

But this year, sheep producers face an additional challenge – the temporary removal of organophosphate (OP) products from the market.

While there has been concern about the effect of OPs on human health, they were an effective option for controlling ectoparasites. They had high levels of efficacy, controlled a broad spectrum of parasites and were persistent – and last year, more than half of all sheep ectoparasite treatments were OPs.

But its likely to be this autumn – or even 2001 – before OPs are available again, while some manufacturers have pulled out of the market altogether.

Experts warn that the risk of sheep carrying scab mites or lice is higher as a result, and many sheep producers will have to rethink their control strategies. Like OPs, other product groups have their pros and cons: Planning ahead and carefully considering the options is vital to ensure appropriate treatment.

Besides concerns about the lack of OPs, sheep producers must also make a concerted effort to control fluke. Wet, mild winters mean it is a greater risk both to sheep and cattle, and it is also being seen in new areas of the country. Added to this, poor profitability in the livestock sector certainly isnt helping.

Despite low profitability, controlling parasites is vital for both welfare and flock or herd returns; ill-thriven animals cant and wont be profitable.

But there is some good news on the horizon; work at the Moredun Institute is concentrating on producing worm and scab vaccines. Both are some way from the market yet, but at least new technology is being developed which is fit for the 21st century.