Industry group Sustainable Control of Parasites in Sheep (Scops) is reminding farmers and contractors not to use organophosphate (OP) products in jetters and showers.
The warning echoes guidance, issued by the Animal Medicines Training Regulatory Authority (Amtra) and supported by the Veterinary Medicines Directorate (VMD), which states OP products are not licensed for such use and can contribute to scab resistance.
The guidance warns that “off label” use could make scab worse by leaving treated sheep carrying hidden scab.
Furthermore, it states sub-lethal exposure using showering or jetting can lead to resistance against diazinon developing.
See also: Dipping sheep to control scab – what you need to know
Lesley Stubbings of Scops said the use of OP products in jetters or showers had gone “widely unchallenged” in the past, but she said the issues faced in controlling scab were now too great and the industry could no longer ignore advice.
“We already know some sheep scab mites are resistant to the injectable products, which means it is more important than ever to preserve the efficacy of the organophosphate dips.
“Exposing scab mites to a sub-lethal dose of OP in jetters and showers is an ideal way to encourage resistance to develop and we cannot afford to continue taking that risk.”
Instead, Ms Stubbings said plunge-dipping is the only way to get the OP down to the skin to ensure the product kills all the mites.
The National Sheep Association (NSA) has also backed the move. Its chief executive Phil Stocker added: “This tough line on jetters and showers has not been taken lightly.
“We know farmers and contractors have invested heavily in such equipment; historically they have even been incentivised by grants and loans to encourage their use, and it is very frustrating to be told they should no longer be used.
“But we cannot emphasise enough how important it is to protect the efficacy of OP dips, which are just not suitable for use in jetters and showers. While our focus is on scab and OPs, sub-lethal doses of any product via a jetter or shower, for any kind of external parasite, are of equal concern.
“I know that abandoning what has long been seen as a useful tool in our armoury, walking away from equipment we were previously encouraging the use of, will anger a lot of farmers and contractors. But NSA and others would not take this hard line if we did not believe the new advice was scientifically sound and absolutely crucial to our future fight against scab.”
For more advice on controlling scab visit the Scops website.