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Monday, 11 November 2019

Don’t let the flies strike!

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As the temperatures and humidity increase, so does the risk of flystrike. Ravensdown Animal Health Area Manager Brent Chamberlain explains how you can stay out of the flystrike zone.

Prevention is always better than cure. Who wants to be chasing sheep to treat for flystrike? If you want to maximise your asset, especially while prices are so good, keep your sheep and lambs healthy and disease-free and they will pay big dividends. It’s simple: if a lamb gets even a small strike, it will stop eating and lose condition, costing you in profit loss and treatment.

Top 4 tips for Flystrike prevention

Understand the life cycle

The first attack comes from pupae that have wintered in the soil. They hatch and start searching for a high-protein food source – carcasses or daggy sheep. Each female has the capacity to produce up to 600 eggs in her lifetime, which means when conditions are right (warm and humid), it’s on! Eggs can hatch, mature to maggots, pupate and hatch new flies within 12-20 days.

Remove temptation

Without food, flies can’t prosper, so the first line of defence is to make your animals unattractive for flystrike.

Dispose of sheep and cattle carcasses by burning or burying. Small mammal and bird carcasses can also become breeding sites and should be disposed of as well. Using fly traps will allow you to better predict the flystrike risk. Paddocks with scrub and thistles attract flies, so try to avoid them where possible. When fly pressure is high avoid ‘hot spots’ where flies congregate such as sheep camps, scrubby gullies and bush margins. Use more exposed, windy spots for grazing if possible.

Prevention is better than the cure

Employ an effective drench programme to reduce parasite burden, regular crutching and pre-emptive application of flystrike treatments. Ensure poorer or vulnerable animals (those suffering from ailments) are treated and monitored accordingly.

While strategic application of chemicals (dips) is critical for flystrike prevention, the application method is just as important, e.g. right amount, right place, right time. Make sure you are getting good coverage of the chemical down to skin level over the areas of the sheep most prone to strike, including the shoulders, back, rump and pizzle on rams.

The most commonly used products are insect growth regulators (IGRs), namely diflubenzuron, cyromazine, triflumuron and dicyclanil, as these will generally ensure flystrike prevention for up to 12 weeks or more. Other products include the synthetic pyrethroids (SPs), spinosad, imidacloprid and organophosphates (OPs).

Two birds one stone

Many of these products also control lice, which is becoming more commonly used as a combination product for fly and lice control. IGR-resistant fly strains do exist, so using combinations will control these and delay the development of resistance in susceptible strains.

If in doubt, seek expert advice on the appropriate dip chemicals to use, along with the correct application method and timing. Below is a helpful table to get you started.


Product


Chemical Group


Active Ingredient


Application method/s


Meat, Milk Wool WHP days

Cyromazine Spray On IGR Cyromazine Spray On 7,35,60
Cyromazine Liquid IGR Cyromazine Plunge, CR, Jetting 7,35,60
Saturate® Gold


IGR
IGR

Cyromazine
Diflubenzuron
Plunge, CR, Jetting 10,35,60
Saturate® Classic IGR Diflubenzuron Plunge, CR, Jetting 7,35,60
Fleeceguard®


IGR
SP

Diflubenzuron Pour On Nil,35,60