Best practice marking of lambs

Page last updated: Wednesday, 1 March 2023 - 12:49pm

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Preventing flystrike of mulesing wounds

When selecting chemicals to prevent flystrike of mulesing wounds, several factors should be considered. Label withh`zzzz xdolding periods (WHP) for meat and wool should be checked prior to using any product. Wool from individually treated animals should be kept separate from the main clip to minimise any chemical residue risk.

Three groups of chemicals are currently registered for treating mulesing wounds: insect growth regulators (IGR) dicyclanil (for example Clik), spinosyn insecticides (for example Extinosad) and organophosphates (OP).

Most blowflies are at least partially resistant to the OP products and present occupational health and safety risks to the operator. For these reasons, OP products are no longer recommended. Diazinon is no longer registered for flock treatments and now only registered for the treatment of individual animals. Powder dressings should not be used as they may delay healing.

When using products for pain relief and prevention of flystrike on a mulesing wound, DPIRD recommends the use of low volume fly treatments, to prevent excess run off and dilution of the pain relief product. It is important to ensure lambs are not disturbed, handled or mustered for at least four weeks after mulesing to allow the wound to heal. Paddock inspections without disturbance should be done at least every three days during the healing process. Table 3 lists products for preventing flystrike at the time of marking.

Table 3 - Products for preventing flystrike at the time of marking (scroll across to see all columns)

Product name

Chemical group

Active ingredient

Mules wound

Strike wound

Volume per treatment band

Meat withholding period

Wool withholding period


(*Clik Plus is not registered for mulesing wounds)



Yes No

4 millilitres (mL)

28 days

3 months

Extinosad & Extinosad Aerosol



Yes Yes

Spray on – until

area is blue & wet

Nil Nil

Mules ‘N Mark II Blowfly Dressing



Yes Yes


14 days

2 months

Defiance S1 & Defiance S Aerosol



Yes Yes

5-8mL/kg but no less than 55mL per head

3 days

14 days

Contact information

Julia Smith
+61 (0)8 9368 3449