Modification of the management practices

Control of the fly population and use of insecticides

The control of the fly population requires what is called an integrated pest management, which means that it results of the combination of several practices.

A new system of trapping has been recently developed. It consist in a trap and chemicals that attract and capture Lucilia cuprina. This system has to be used intensively and constantly in order to significantly decrease the fly population, with cooperation of several neighboring properties. Moreover, even if it can decrease the fly population by up to 50%, its effectiveness in reducing the number of strike is controversial and hard to measure, this feature varying with the weather.

Insecticides have also been developed against Lucilia cuprina. They are organophosphates, insects growth regulators and spinosyn. Their efficiency varies from one another. Moreover, they cannot be applied to sheep with greater than 6 weeks growth wool because of the unacceptable residues present on the wool at the next shearing. Moreover, their application has to be strictly regulated in order to not develop a quick resistance of the fly to them.

A vaccine against the larvae of Lucilia cuprina has also been developed. Its efficiency seems to be reasonably good, even against other flies. However, it has not be widely used yet.

Sheep management

Shearing prior to the early spring and crutching prior to late summer/autumn will minimize potential problems. Lambing is also timed to started following either shearing or crutching to reduce breech strike associated with urine and afterbirth in long wool.

To this date, no management practice used as alternative to mulesing has been shown to be as efficient as the surgical operation. To be the most efficient, the options must be timed and combined with a strategic chemical use, a good timing of shearing and crutching associated with an adequate timing for lambing.

Relative risk of flystrike along the year and its modification thank to  timed management practices. Adapted from Managing Breech Flystrike by AWI

 Breeding for flystrike resistance

Breeding for flystrike resistance consist in selecting the sheep that will be allowed to reproduce on their low susceptibility to flystrike. This pass through a selection for a bigger bare area of the breech, less wrinkles and shorter tail with less wool on the lower and side parts. Breeding for flystrike resistance alone will probably not be sufficient to prevent the degree of protection provided by mulesing. It will have to be combined with adoption of new management practices. Moreover, the selection will have to be balance with the production goals that require the maximum of skin surface to produce a maximum of wool. This selective breeding has already be adopted by an important number of wool producers.



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