Flystrike costs the Australian sheep industry approximately $173 million annually, due to lost production, treatment costs and deaths. Reducing the risk of flystrike has immense benefits to the health and wellbeing of the sheep and productivity.
The major fly responsible for flystrike in sheep is the green blowfly, Lucilia cuprina. Lucilia cuprina is thought to be responsible for 90% of flystrike cases.
Lucilia cuprina begins to become active when temperatures are above 15oC and is most active when temperatures are between 26 – 36oC. It prefers calm conditions. Each female fly can have up to 300 viable offspring and, with a 21-day life cycle, when conditions are optimal, fly numbers can increase rapidly.
The fly has a small flight range, so most of the flies you see are probably produced on your own property. The fly is attracted to odour and moisture, so the risk of flystrike increases when there is regular, consistent rainfall that keeps the sheep’s skin moist.
The sheep most susceptible to flystrike are those with breech wrinkles, long wool, dags, urine stain, fleece rot, dermatitis and/or wounds. Plus, sheep that have been previously fly-struck have a relatively higher likelihood of being re-struck.
The prevention of flystrike requires an integrated plan and includes the following:
selection of sheep and marking of lambs to produce a flock with a relatively low susceptibility to flystrike
shearing and crutching timed before the peak flystrike risk period
correct use of preventative chemicals timed to give protection during the peak flystrike risk period
worm control and dietary management to help reduce the prevalence of dags
selection of relatively open, windy, dry paddocks
removal of infective material and carcasses that may attract flies.
As conditions become more favourable to flystrike, sheep should be monitored more regularly for flystrike.
If a fly-struck sheep is found, the affected area should be immediately treated by clipping close to the skin, dressed to prevent a re-strike, and the sheep should be moved to a hospital paddock to reduce the risk to the rest of the flock. Any maggots should be collected and killed to help reduce the build-up of fly numbers.
For further advice please contact your local veterinarian or Agriculture Victoria veterinary or animal health officer, or visit websites Home – FlyBoss and On-Farm Research.
