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.
| Product name | Chemical group | Active ingredient | Mules wound | Strike wound | Volume per treatment band | Meat withholding period | Wool withholding period |
|---|---|---|---|---|---|---|---|
| Clik* (*Clik Plus is not registered for mulesing wounds) | IGR | Dicyclanil | Yes | No | 4 millilitres (mL) | 28 days | 3 months |
| Extinosad & Extinosad Aerosol | Spinosin | Spinosad | Yes | Yes | Spray on – until area is blue & wet | Nil | Nil |
| Mules ‘N Mark II Blowfly Dressing | OP | Propetamphos | Yes | Yes | 30mL | 14 days | 2 months |
| Defiance S1 & Defiance S Aerosol | OP | Chlorfenvinphos | Yes | Yes | 5-8mL/kg but no less than 55mL per head | 3 days | 14 days |