SHEEP farmers have been warned they must follow safety guidelines when dipping their sheep.

Any flouting of rules, particularly involving organophosphorous dips, could lead to swift action by the authorities.

Vet Peter Watson told a seminar at the fair that there were rumours of farmers not using the closed systems introduced for OP dips. "Rumours are spreading that people are not using them in the field and the veterinary products committee has let it be known that, if that is the case, they may withdraw those products again," he said.

The products had been withdrawn following health fears and were allowed back on the market only after cans had been designed to avoid any risk of contact with the user.

He said there was no doubt that such systems would apply to all dips in the future, not just organophosphorous.

Mr Watson, who was involved at a national level with the debate on sheep dips, also said the Environment Agency was always looking out for pollution problems caused by the dips.

There was a very low tolerance level in rivers and he said it would take only one cat wearing a new flea collar, containing OP, to drown in a river to push the level over the limit.

A few years ago, regulatory bodies had expressed concern about dip residues in sheep fleeces and had proposed that they should not be shorn for two months after dipping.

"We fought that off, but it is still on the agenda and may come back so just be aware of that," Mr Watson warned the meeting.

In the carpet manufacturing area of the West Midlands, some disquiet had been expressed about the possible contamination of water from dip residues on fleeces used in the manufacturing process.

Mr Watson said that, since the end of compulsory annual dipping, sheep scab incidents had risen.

He sat on the committee which was consulted about relaxing the dipping order and said none of them had wanted it lifting.

Sheep scab was the most serious external parasite to affect sheep and was difficult to eradicate. Every sheep in the flock had to be treated as well as any others that might come in contact with them,such as neighbour's flocks on the open moor.

"The Government eradication scheme ended and scab is pretty widespread across the country," said Mr Watson. "It does seem to have gained resistance to some of the chemicals we have used to eradicate it. If it becomes less sensitive to what we have available, it may become a bigger problem."

He said all treatments had the potential to do damage and handling the dip concentrate was considered the most hazardous process. That was why it was essential to do it safely and properly.

There was not much money available for research and development to fight scab because it was very much a local UK issue, said Mr Watson. "At the moment I am not aware of anyone doing any work on sheep parasites specifically, anywhere in the world," he said. "It is not a big priority area because all the drugs we have in veterinary medicine come from human medicine, with the one exception of head lice.