The misuse of organophosphate dips (OP) in the control of sheep scab could be detrimental in causing resistance if misused, according to Jason Barley from the Agri-Food and Biosciences Institute’s (AFBI’s) Veterinary Sciences Division.
Barley was speaking at the Teagasc National Hill Sheep Conference at the Westlodge Hotel in Bantry, Co. Cork on Wednesday evening (February 15), when the topic of sheep scab arose.
A member of the audience asked: ‘Is it only injectables that sheep scab is becoming resistant to, or is it also the dips too?’
“There is no resistance to dips presently, but if we misuse these products in jetters, showers and sprayers, there could be in time,” Barley answered.
“It’s not the dips at the moment but what I will say is, which to my knowledge is the same for both the UK and here in Ireland, is that there are no dips that are licensed to be used through jetters, showers or sprayers for the treatment of sheep scab,” he explained.
“It’s an untruth that you can put a product formulated for dipping through a jetter shower or sprayer and get the same effect.
“If you use a sheep dip through one of a jetter, sprayer or shower, you may get a dampening down of the infestation, but you will not cure it.
“Rather, you will expose those mite populations to a low and persistent level of OP and that is exactly how resistance develops.
“It can and has happened. There are resistant strains of scab in South Africa to OP dips,” he said.