Blowfly warning for Northern sheep farmers

Sheep farmers in the North of England are being warned of the risk of blowfly strike as the local Blowfly Watch risk alert has been raised to red.

The free Blowfly Watch service, run in partnership with NADIS, uses a combination of factors – including soil temperature and humidity – to predict a blowfly strike risk in a 40km area.

Matt Colston, ruminant technical consultant at Elanco, says it is worth considering early preventative action when the service issues risk alerts in your area.

“Damage happens fast – it can take as little as 36 hours from an egg being laid on a sheep to maggots eating its flesh[1] – so prevention is better than waiting to see a struck lamb before treating the whole flock,” he adds.

“You can protect your flock by applying an Insect Growth Regulator (IGR), such as those in the CLiK™ range.”

He says the range provides options for all types of sheep, whatever the management system – with protection periods ranging from eight to 19 weeks, and meat withdrawal periods ranging from seven to 40 days.

Mr Colston’s top tips for applying a preventative treatment include:

• Use an appropriate applicator gun with a fan spray nozzle and be sure to carefully calibrate it before use
• Apply to a clean fleece; clip or dag any dirty animals before application
• Apply the product in a band approximately 10 cm wide (holding the gun approximately 45cm from the sheep).
• Apply the total required dose one quarter at a time, using the four-stroke method – from mid-shoulder to the middle of the back; from the middle of the back to the top of the tail; from one side of the tail to the crutch; and from the other side of the tail to the crutch

Mr Colston says the efficacy of preventative treatment relies on the product being applied to clean sheep – aided by effective worm control, as well as actions such as dagging and timely shearing.

“Worm management plays a valuable role in preventing strike, because scouring, due to worms, can cause dirty backends and encourage flies,” he adds.

“Regularly faecal egg counting will help identify worm burdens early and prompt treatment before lambs scour.”

Farmers can sign up to Elanco’s Blowfly Watch alerts online at www.blowflywatch.co.uk and report cases of strike on the Elanco Blowfly Tracker at https://bit.ly/3Fn3avi

[1] Blowfly strike: biology, epidemiology and control - Wall - 2015 - In Practice - Wiley Online Library