Checking worm burdens with a WormTest is essential for correct and timely drenching decisions. The result is healthy sheep without unnecessary drenching. WormTests are the best basis for drenching decisions outside of recommended times. Pale skin and eyes, bottle-jaw, weight loss, a tail in the mob, and deaths may mean that your sheep need drenching. If so, these signs occur well after production losses from worms are already occurring in the mob. WormTests give early warning of significant production losses.
Checking worm burdens throughout the year using WormTests is a critical part of the WormBoss worm control program.
Most WormTests are done through a laboratory. However, worm egg counts (but usually not larval cultures) can be done by producers if they have the equipment and skills.
WormTest at least one in every three mobs that are similar regarding drenching history, paddock type and class of sheep.
Testing representative mobs saves the cost of testing all mobs. But this assumes the mobs, their paddocks and drenching history are very similar. If in doubt, test additional mobs.
Use of the Barbervax® program is an optional strategy to control barber’s pole worm; it will not control other worms. Routine drenching of lambs at weaning and routine WormTest times will still apply, however non-routine drenching will be reduced when Barbervax is used correctly. Protection against barber’s pole worms requires three initial ‘primer’ vaccinations at 3–4 week intervals. A vaccination schedule can be customised by a professional advisor.
Lambs or hoggets not previously vaccinated
Hoggets vaccinated as lambs the previous year
Breeding ewes not previously vaccinated (assumes a spring lambing)
Breeding ewes vaccinated the previous year
Note: V=vaccination, the number (1–6) refers to first, second (and so on) vaccination in the series given in one barber’s pole worm season.
It is also important to follow the routine drench and WormTest times shown below.
In this region there are two situations where sheep should be drenched without a prior WormTest, these are:
In both cases use a drench known to be effective on your property. Preferably use a short-acting treatment, and where possible, use a multi-active combination. After these drenches, move the sheep into prepared low worm-risk paddocks.
Note: An ‘active’ is the specific chemical in a drench responsible for killing worms. Some drenches contain more than one active and are called ‘multi-active’ or ‘combination’ drenches. See Drench groups and actives.
WormTests can be done at any time; however there are certain routine times to WormTest (preferably with a larval culture):
The timing of WormTests and drenches will vary between farms and seasons. Use the Drench Decision Guide (see below) to weigh up important factors when deciding when to drench or WormTest on your property. These factors are signs of worms, time since last drench, the persistence of the last drench, WormTest results, recent rainfall, and condition of sheep and pastures.
If drenching is done for other reasons (such as an early drench before holidays or harvesting), recommence WormTests 4–6 weeks (summer) or 6–8 weeks (winter) after the drench was given.
Then use the Drench Decision Guide to decide when to drench or WormTest again.
Sheep do not need to be yarded for a WormTest. Collect fresh dung from the paddock. Obtain WormTest kits or sample collection details from laboratories or resellers in your area. Follow the instructions provided in the kit.
If you do your own worm egg counts, use the ‘bulk’ sampling method where all of the dung is collected into one container.
See the following fact sheet ‘Checking a mob of sheep for worms with a WormTest’.
The Drench Decision Guide is reliable and helps to simplify decisions. There is a version of the Drench Decision Guide for each WormBoss region.
The guides consider:
The Drench Decision Guide will recommend:
Results from the Drench Decision Guide can be applied to mobs without a WormTest if other mobs (same class, and similar drenching and paddock histories) have been tested. If in doubt, WormTest the mob.
You can use the Drench Decision Guide at any time, whether you are contemplating drenching a mob now or in coming weeks. Not all situations require a WormTest: the Drench Decision Guide will recommend when these should be done.
See the Drench Decision Guide.