Sheep farmers warned blowfly strike risk remains high this autumn

Sheep farmers are being warned that blowfly strike remains an active threat this autumn, with recent rain and mild temperatures keeping flies active and cases still being reported across the country.

The Sustainable Control of Parasites in Sheep (SCOPS) group said the shift from a warm, dry summer to damper conditions had prolonged the risk in many areas.

Above-average temperatures in parts of the country during September and October have also helped keep flies active later into the season.

SCOPS is urging flock owners to review their fly control plans, particularly where preventative treatments were applied earlier in the summer.

Some products may now be approaching the end of their stated protection period, meaning treatment dates, product persistence and higher-risk animals should be checked closely.

Blowfly strike can develop quickly, especially where fleeces are wet or dirty.

Sheep that are scouring, have daggy back ends, wounds, footrot or reduced mobility are among those most at risk and should be prioritised for regular checks.

Nerys Wright, technical adviser for SCOPS, said farmers were still reporting active blowfly strike in their flocks.

“Several farmers have reported active blowfly strike within their flocks this week,” she said.

“It is easy to assume the risk is over once we move into autumn, but the combination of recent rain and temperatures that are still relatively mild for the time of year means blowflies remain a real threat in many areas.”

Wright said farmers should remain vigilant where earlier treatments may be wearing off. “The key message is to remain vigilant,” she said.

“If a product applied earlier in the season is coming towards the end of its protection period, it's worth checking the label and your treatment records, and keeping a close eye on higher-risk sheep.”

Olly Matthews, deputy chair of SCOPS and a sheep farmer, said the calendar should not be used as a guide to when blowfly risk has ended.

“From a practical farming perspective, this is the time of year when it's tempting to think blowfly season is winding down, but sheep and flies do not read the calendar,” he said. “If conditions suit, strike can still occur.”

SCOPS said the same mild and wet conditions were also extending the traditional gut worm season, meaning parasite challenges may continue later into the year.

Farmers are being advised to use faecal egg counts alongside lamb growth rates and ewe body condition to help assess whether treatment may be needed.

This is particularly important where lambs are failing to perform as expected despite adequate nutrition.

SCOPS also warned that clinical signs should not be overlooked, as worm egg counts can sometimes lag behind infection by several weeks.

Where lambs are failing to thrive or deaths occur, post-mortem examinations can help identify the cause and guide the most appropriate response.

Farmers are being encouraged to continue checking vulnerable sheep closely, review treatment records and product labels, and seek veterinary or adviser guidance where concerns remain.