Worms, lice and blowflies are the three biggest health problems for
the Australian sheep industry and represent more than $700 million
in direct and indirect costs to Australian woolgrowers every year. Forecasts suggest that these costs could increase significantly, due
to increased parasite resistance to chemical control, impeded market
access from pesticide residues, and growing occupational health and
safety concerns. There is an urgent need to develop parasite control programs that
do not strongly select for chemical resistance, that produce nil or
very low residue wool at harvest, and that do not pose human health
concerns. Australian Wool Innovation is working with universities, government
departments and hundreds of Australian woolgrowers to develop Integrated
Parasite Management programs for the major sheep producing regions
of Australia. There is a major message coming from the Integrated Parasite Management-sheep
(IPM-s) project in terms of worm control – every farm is different
– but IPM-s programs will provide the flexibility to deal with this
variability. Sheep farmers need to develop and monitor their IPM-s programs in
consultation with a veterinary or animal health expert who is familiar
with both the research and the subtleties of their local environment. Programs need to consider:
|
|
Worms
- Testing for drench resistance to know which drenches are
effective against the parasites on your property
- Monitoring worm egg counts at critical times of the year
in different mobs
- Drenching only after monitoring of worm egg counts indicate
the need
- Timing drenches to reduce worm burdens or slow the development
of drench resistance
- Using grazing management strategies to reduce exposure
of sheep to worms on pasture, such as the ‘Smart Grazing’
approach developed by the Mackinnon Project for winter rainfall
regions, or intensive rotational grazing, or sheep-cattle
interchange in summer rainfall regions
- Selecting sheep for both increased resistance to worms
(low worm egg count) and, in winter rainfall regions, for
less scouring (low dag score)
- Setting targets for ewe condition score at lambing and
weaner bodyweight over summer-autumn and monitoring progress
towards meeting these targets
- Use of protein meal supplements during late pregnancy in
summer rainfall regions to increase worm resistance.
|
Lice
- Instituting a lice biosecurity plan that could include checking
lice history and quarantining purchased or agisted sheep, preventing
strays, guarding against the introduction of lice by contractors
or shearers who have recently been on an infested property and coordinating
treatment with neighbours
- Monitoring for lice before shearing, before crutching and at other
times when sheep are yarded
- If lice are detected, treating thoroughly with an effective chemical
at next shearing regardless of whether or not a long wool treatment
was used – ALL sheep must be mustered and treated.
Flystrike
- Correct tail docking and mulesing (or a replacement technology)
- Strategic timing of crutching and shearing
- Selecting sheep that have reduced susceptibility to both body and
breech strike
- Controlling scouring through good worm control, selection for low
dag score and nutritional management
- Strategic application of pesticides with regard to fly biology,
flystrike risk and residues
- Other methods that may be applicable on some properties – including
choice of low flystrike risk paddocks for the most susceptible sheep
and the strategic use of flytraps.
|