To minimise the chemical residues left behind from the control of external parasites, whilst simultaneously driving lice and blowfly infestations down, AWI provides Australian woolgrowers with guides to best practice. AWI is currently developing new diagnostic and treatment methods and is funding R&D into flystrike prevention options.

Background

Lice are estimated to cost the Australian sheep industry $125m per year. This is less than the $169m estimate of 1995, no doubt due to a reduction in sheep numbers, but also the wide-spread use of off-shears pour-ons.

Control of lice relies on good flock management - to prevent lice being introduced - and where an infestation is discovered, treatment with an effective lousicide. A number of tools are available to prevent and treat blowfly strike, including breech modification, tail docking, jetting with chemicals, fly traps, and breeding for fly-resistant sheep.

Blowflies are estimated to cost $280m per year, considerably more than the $161m estimate of 1995. These costs include mortalities and production losses (reduced wool cut, stained wool, cotts, lowered staple strength), as well as the direct costs of control (mainly jetting treatments and labour).

The management of external parasites onfarm is underway against a backdrop including:

• Gradual development of resistance to chemicals by insects 
• Possible restrictions on market access, in the European Union in particular, if wool contains pesticide residues
• Changing public expectations of animal welfare in regard to flystrike prevention 
• Increased scrutiny of the occupational health and safety implications of certain chemicals, notably diazinon
• Increased scrutiny of the on-farm environmental implications of sheep dips.
  AWI is addressing these threats, and attempting to lower the cost of louse and fly control for wool producers, in four ways:
  • Better use of existing technologies 
  • New products and practices 
  • New diagnostic tests 
  • Replacing/improving undesirable practices

Better use of existing technologies

Control of lice, flies and worms can be improved in many sheep flocks by applying principles of integrated parasite management (IPM). IPM means that a range of chemical and non-chemical methods are brought together to tackle the parasite problem.

AWI's flagship project in this area is the Integrated Parasite Management - sheep (IPM-s) project. Since 2004, more than $3 million has been invested invested to develop, apply and test IPM systems across a range of wool production environments. There are 23 IPM-s demonstration farms across Australia. Read the IPM section or contact Lewis Kahn for further information.

LiceSense

LiceSense is a woolgrowers’ guide to managing sheep lice in response to spreading lice infestations in all states. Sheep lice are an insidious and costly pest so it is important to find them early to reduce their impact.

LiceSense is produced by AWI.

The LiceSense guide is a ‘refresher’ for lice management principles, which are:

1. find lice early
2. plan your flock protection
3. know the costs and gains
4. plan a successful treatment.

Click here to download the LiceSense guide in PDF (1.03 Mb).

The LiceSense guide doesn't cover all the details of lice management, so woolgrowers should consider attending extra training days and seeking advice when planning flock protection and treatment.  For more information on training, visit the Making More From Sheep website. For further advice on lice management, contact the primary industries/agriculture or related organisation in your state.

For more information on lice management, visit AWI’s LiceBoss information at www.wool.com/liceboss.

New products and practices

It is important that there is a steady stream of new tools being developed for the control of lice and flies.

AWI has a number of projects in this area, including:

• The blowfly genome project 'mapped' about 90% of the blowfly genetic code and identified 400 genes considered to be unique to the blowfly. This will hopefully help identify weak points that could be targeted by new insecticides, vaccines or other treatments. It may also provide useful information on the mechanism of resistance and how best to avoid it. This very basic research is still several years from producing commercial results.
• Biological control , using a fungus with an affinity for lice, shows promise, but much work needs to be done to reach the goal of a commercially viable product.
• Investigating the potential for a new class of louse and fly treatments based on a naturally-occurring protein which has not been targeted before. This is also basic research, several years away from commercial results.
• Sheep are affected by both breech strike and body strike – FlyBoss (http://www.flyboss.org.au/) provides you with the latest information to reduce the risk through management and breeding approaches and provides information on treatment of flystrike outbreaks.
  

New diagnostic tests

A priority for AWI has been to develop a test for the detection of lice on sheep. Lice can be very difficult to detect by eye, especially when the population is low. As a result, many producers treat for lice even though lice are not present - as an 'insurance policy'. Surveys suggest that up to 80 per cent of flocks are treated annually despite only about 30 per cent having lice.

A lice detection test would benefit woolgrowers by saving the cost of treatment, reducing the residue load on the clip, and reducing the resistance pressure on the chemicals used. A further benefit would be the identification of sheep infested with too few lice to be identified at shearing, but sufficient to become a problem before the next shearing.

An accurate new test that can diagnose lice infestations at shearing is now available from NSW DPI.

Replacing/improving undesirable practices

Mulesing is highly effective at reducing the incidence of breech flystrike in sheep. With changing community views on animal welfare, it has become the subject of criticism by animal welfare groups.

AWI is funding several projects that aim to develop alternative flystrike prevention options. See futher information about Flystrike prevention in Australian sheep.

See also: internal parasites.