Royal Highland Show: Flocks face flesh-eating blowfly risk

Sheep farmers are being warned to take action to protect their flock from blowfly strike, with unpredictable weather making the risk variable this year.

Reports of fly strike have already been recorded, with even the smallest challenge having a significant impact on individual sheep and flock production.  

Sheep vet Matt Colston from Elanco Animal Health encouraged farmers to take action to protect their flock due to the welfare and economic consequences of an outbreak.

See also: Check out the 2015 Highland Show photo gallery

Speaking to Farmers Weekly at the Royal Highland Show, Mr Colston said: “Even in 2012 when it was a miserable summer sheep were still getting struck.

Facts about blowfly strike

  • As soil temperatures rise above 9C overwintered blowfly larvae will start to develop in adult blowflies
  • Flies are attracted by the odours of excessive sweating and decaying organic matter
  • Blowfly strike occurs locally and is likely to occur in warmer, humid weather
  • Blowfly strike can happen very fast and, left unprotected, sheep can die within a matter of days

“The risk of blowfly is variable at the moment, but it only takes a couple of warm days for the flies to hatch and there will be a serious challenge.”

Often by the time a strike challenge has been identified it can be too late in terms of the knock-on consequences on animal performance.

Mr Colston said it only took two to three days from eggs being laid to them hatching into second-stage maggots, which then break through the skin and start eating the flesh.

He said even a small outbreak could give sheep open wounds as big as a hand.

“It not only causes pain to sheep, but it also sends lambs backwards as even small scale strike will stop sheep and lambs eating.”

Mr Colston explained that farmers needed to look at protecting their stock with insect growth regulators, which target blowfly specifically and stop maggots from moulting.

He said: “Have a discussion with your vet or prescriber about the best product to use as different products have different meat withdrawal times. It also depends on factors such as when you are shearing.”

Mr Colston also encouraged farmers to look at protecting their flock right throughout the summer and into autumn.

“Last October we were still seeing strike, so farmers need to be planning for fly cover until we get a significant frost. One product can protect sheep for up to 16 weeks,” he added.

See also: Watch a video on blowfly strike