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Blowfly strategy crucial to viable flock management

Peregrine runs a flock of just under 1000 ewes, based in Devon. The structure of his business is set up to maximise genetic improvement and has previously won the AHDB Beef and Lamb award as the Most Improved Flock of Lleyn sheep in England, delivering the greatest genetic gain for commercial characteristics over a 12-month period.

Peregrine values the importance of integrating proper preventative blowfly treatment into his management strategy. "If the weather is good for growing grass, it’s good for blowfly," he says. "You’ve just got to bite the bullet and get on with a management strategy right at the beginning of the season."

He is keen to go beyond the standard perception of blowfly strike as harmful solely to animal health and productivity: "A lot of farms don’t consider their time as part of the outgoing costs. As a farmer you never have enough time for everything you’d like to do, so you have to value it. Time is money, ultimately."

A recent study shows that the labour cost to handle a struck animal is £10¹, but Peregrine believes the cost impacts don’t stop there if untreated. "Essentially, without treatment you must constantly be checking the flock, always being vigilant," he says. "Checking general health is a quick job, but closely looking for blowfly is not and can very quickly impact the viability and management of the flock."

Farm Facts
  • Located in Devon
  • Flock of just under 1000 Lleyn ewes
  • 150ha, mainly lowland hills
  • Lambing indoors, with doubles and triples shorn at Winter.
  • Commercial breeder, set up for maximising genetic improvements

The cost of blowfly strike

Blowfly strike occurs when blowfly eggs reach second-stage maggots, which feed on the sheep’s flesh, resulting in serious damage and distress to the animal and, as shown in a recent study¹, causes a £10 production loss per struck lamb. Although preventative treatment is a comparatively minor investment, many farmers get caught out every year, partly because of the changing timing of blowfly season. "Here in the south, the fly season is pretty long," he says. "The seasons are getting longer too. If you’re not prepared, your sheep can be damaged or even lost. It’s dispiriting when it happens. Even without the loss of sheep, there’s a loss of performance and the extra cost of treatment when strike hits."

"You can waste a huge amount of time holding back, even for a week or two, just watching the sheep closely. Ultimately, there’s more cost-effective and time-effective ways of managing your business."

Plan for effective management

Peregrine lambs indoors and shears the doubles and triples in winter rather than summer, usually just before Christmas. As a result, the flock are susceptible to blowfly for a large part of the season, unless treated. The flock is turned out after lambing, around the beginning of March. "If struck, the sheep can lose a lot of weight," he says. "It doesn’t take much to be knocked back by a couple of months and disrupt the entire schedule. That’s why implementing preventative treatment is so important – we use CLiK EXTRA as it gives the extended coverage we need – as ultimately, you’re saving yourself time and money. It makes no sense leaving it to chance."

Central to his farm management strategy, Peregrine applies blowfly treatment in a big pen, to avoid compromising the application, and stop sheep rubbing off the product. He calibrates and recalibrates the gun as he goes as required by the animal’s weight to ensure the correct dosage.

Blowfly Strike – the impact in numbers
  • Costs the farming industry approx. £2.2m a year²
  • 79% of farmers believe the blowfly season is getting longer or starting earlier³
  • 94% of farmers have been caught out by blowfly strike in the past³
  • 99% of farmers have suffered financial loss due to blowfly strike³
  • 70% of farmers report significant time lost due to blowfly strike³

Importance of preparation

The success of Peregrine has been recognised in the industry, and he attributes this to his careful planning, while not allowing himself to become complacent. "It’s important to have a good strategy in place, but equally important is to consider the variables – making sure you have your treatment ready to go, to be prepared for changes in the weather, and to stay aware of what’s going on with your flock in terms of their health. No farmer should let themselves be caught unprepared."

¹ Richard Wall and Fiona Lovatt (2015). Blowfly strike: biology, epidemiology and control, In Practice 37:181-188 doi:10.1136/inp.h1434.
² AHDB BRP Manual 10.
³ Survey of 130 sheep farmers, Elanco April 2016.
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