If you are concerned that your sheep may need drenching now, but are unsure, please go to the Drench Decision Guide for your region.
A WormTest or worm egg count is generally the most accurate means to determine the burden of worms carried by an individual sheep or a mob, however there are other ways to assess whether sheep have worms and what level of worms exist.
Unfortunately, most rely on signs that show significant production loss from worms is already occurring.
When the costs of drench, labour, testing and production loss are weighed up, the most profitable option for worm control is always to implement an integrated control program that includes regular monitoring with worm egg counts, combined with drenching before signs become obvious, but not unnecessarily soon.
WormBoss has practical and cost-effective integrated Worm Control Program for your region as well as Drench Decision Guides to help with deciding when to drench.
Weighing and condition or fat scoring
Scour worms cause a loss of appetite resulting in weight loss. This can be seen by loss of body weight and also by a reduction in condition score or fat score (note that condition scoring and fat scoring are done differently, but both will indicate the loss of weight).
Regular weighing or condition or fat scoring of animals either on a mob basis or individuals can show when these start to decline. However, weight loss often results from other causes, in particular, a decline in pasture quality, quantity or both.
A WormTest is more accurate, less labour-intensive, and a less stressful to the sheep method to monitor the worm burden of a mob; however, observed weight loss can be a useful trigger to carry out a WormTest.
Assessing the colour of mucous membranes
Mucous membranes are the moist areas of ‘internal skin’, such as inside the mouth (gums), nasal cavity, eyelids and vagina.
Where these do not have dark pigment, they can be used to observe the richness of colour in the blood. Normal healthy sheep with have very dark pink to red mucous membranes. Sheep suffering from anaemia, which can occur with barber’s pole worm and liver fluke, will have paler membranes; in severe cases they can be almost white. Liver fluke may also cause jaundice, which will cause a yellow colour in the membranes.
Other worms do not cause anaemia, however, there are other causes such as the blood parasite Mycoplasma bovis and copper deficiency; a WormTest will help when diagnosing the cause of anemia.
Checking the colour of the inside of the lower eyelid has been standardized into a test for worms in South Africa, called the FAMACHA© Test.
In South Africa, this test is only feasible as they have severe drench resistance (with the resulting lack of drenching options) and extremely cheap labour. Mobs are yarded and every individual is tested and recorded each 1–2 weeks during the worm season.
This test is not considered useful in commercial Australian flocks. The ability to note the progress of anaemia and drench at the right time relies on frequent whole-flock monitoring. Checking a handful of sheep every now and again is not a suitable substitute.
Regular scheduled WormTests combined with a planned Worm Control Program is ultimately cheaper and more effective.
Nevertheless, checking for anaemia is useful in overall monitoring of signs of worms, and if present, should generally trigger the need to conduct a WormTest on the mob.
There may be a role for this test in small hobby flocks (under 50 sheep) where frequent monitoring is possible.
The dog or bike test
Chasing the sheep with a dog or on the bike, and seeing whether some are lagging (a tail in the mob), or whether some collapse, is a very crude indicator of a worm infection. If lagging or collapse are evident—and it is due to worms, and not some other cause— sheep are already suffering from production loss that has generally warranted earlier drenching. If a few sheep do lag or collapse when being mustered, individuals can be treated for worms, but the mob should also be WormTested to see if drenching should be done now.
A suitable program of WormTests is more cost-effective, and can be found in your Worm Control Program.
Other signs of worms
Worms cause a variety of signs, however all of these signs can occur with other diseases. Refer to our signs of worms page to see a full list.
When any of these signs are apparent, a WormTest of the mob may be appropriate. If only a small number of sheep are showing signs is may be useful to treat these individually while awaiting your WormTest results. If more than 10% of the mob are showing signs, it may be appropriate to drench the mob. The Drench Decision Guide for your region will provide a recommendation on whether to drench or to test.
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