Sheep farmers could be undermining efforts to reduce unnecessary antibiotic use by routinely treating orf with antibiotics, despite the disease being viral and antibiotics often having little effect, new research suggests.
The findings raise concerns around antimicrobial resistance and inappropriate medicine use in the sheep sector, particularly where antibiotics are used as a first-line response.
The study, carried out by the Royal Veterinary College (RVC) and NoBACZ Healthcare, found that 65% of farmers surveyed used a topical antibiotic spray to treat orf.
Around a quarter of respondents also said they had used injectable antibiotics, despite these having no impact on viral lesions unless a secondary bacterial infection is present.
While antibiotics were the most commonly reported treatment, other approaches were also used. Pain relief featured in 34% of responses, while 14% of farmers said they relied on rock salt licks.
The research confirmed that orf remains widespread across the UK sheep sector. The disease had been present on 73% of respondents’ farms in the previous 12 months.
Among those affected, 90% reported cases in naturally reared lambs. Half said adult ewes had been affected, while 11% reported infection in rams.
The study also highlighted the zoonotic risk of the disease. One third of farmers said they had contracted orf themselves at some point, with 20% reporting infection within the past year.
Despite the high prevalence, uptake of vaccination remains limited. Only 23% of farmers surveyed said they were using the licensed orf vaccine.
This is despite National Office of Animal Health (NOAH) Livestock Vaccination Guidelines categorising orf vaccination as a category two recommendation for flocks where the disease is already present.
David Charles, veterinary surgeon at NoBACZ Healthcare and one of the study’s researchers, said the scale of the problem had received little attention in recent years. He said: “The impact of orf on flocks is huge, and little has been done to assess treatment approaches or the economic impact of orf for over a decade.”
The research estimated a median cost of £5 per affected lamb. Farmers identified treatment costs, time spent managing outbreaks and mastitis in ewes as the main contributors to those losses.
Charles said managing outbreaks remained difficult. “Management of an orf outbreak can be challenging and there is currently no licensed treatment for the disease,” he said.
He added: “Antibiotics are often not an appropriate choice for the management of orf, and proven antibiotic-free alternatives are a more responsible first choice.”
The study also captured farmer experience of alternative management approaches. One participant was Eleri Williams, a sheep farmer from Denbighshire in Wales.
She said orf had been a recurring issue on her farm. “We see orf cases each season with approximately 50% of lambs affected with lesions around their muzzle, which is followed by transfer onto ewes’ teats,” she said.
“In the past we would typically use antibiotic spray to reduce the risk of secondary infection, together with orf buckets and rock salt, however infection would be prolonged, leading to loss of body condition,” she added.
Williams said feeding problems had, in some cases, led to losses. “In the very worst cases we’ve lost lambs,” she said.
She said she trialled an antibiotic-free barrier product during the most recent lambing season. “Last year we used Ambugreen for the first time and found significantly fewer instances of orf, with only 20% of lambs and no ewes affected,” she said.
“The Ambugreen barrier seemed to limit the spread of infection between the lambs and onto ewes’ teats, drying the lesions rapidly and improving healing time,” she added.
Williams said lamb performance improved as a result. “We found that lambs kept better body condition throughout treatment and recovery as they were still able to drink from their mothers,” she said.
She added that recovery times were shorter. “In our worst cases, orf was gone within 10–14 days,” she said.
The researchers said the findings highlight the need for clearer guidance and greater awareness around effective orf management, particularly as pressure grows to reduce unnecessary antibiotic use in livestock.
