Assessing worm burdens without a WormTest


Sheep

If you are concerned that your sheep may need drenching now, but are unsure, please go to the Drench Decision Guide for your region. 

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 Programs for your region as well as Drench Decision Guides to help with deciding when to drench.

Haemonchus Dipstick Test

This test is only suitable for identifying the presence of barber’s pole worm, because it tests for blood (sucked from the sheep by the worms) in the dung.

This test can be used at any time, but is most useful in spring, summer and autumn to detect rapidly developing barber’s pole worm infections, particularly:

  • In mobs that were not tested using a WormTest
  • In any mobs between WormTests
  • Two weeks after ideal weather conditions for worms have occurred (warm and rainy for some days), and when pastures are likely to be heavily contaminated with infective worm larvae

The advantages of this test are:

  • It is able to pick up the presence of immature barber’s pole worms before they are laying eggs
  • It is cheap and simple and can be done on-farm with immediate results

Contact Ancare for more details on the Haemonchus Dipstick Test.

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.

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 does require 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.


Goats

#If you are concerned that your goats may need drenching now, but are unsure, please go to the Drench Decision Guide for your region.  

WormTest  or worm egg count is generally the most accurate means to determine the burden of worms carried by an individual goat or groups of similar goats, however there are other ways to assess whether goats have worms and what level of worms exist. 

Unfortunately, most are lagging indicators and rely on signs of significant production loss from worms having already occurred. 

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 grazing management, good nutrition, breeding for worm resistance and regular monitoring with worm egg counts to ensure that drenching occurs at the right time and before signs become obvious. 

WormBoss has practical and cost-effective integrated Worm Control Programs for your region as well as Drench Decision Guides to help with deciding when to drench. 

The other methods of identifying if goats may be suffering from worms include the following:

Assessing barber’s pole worm infection

Assessing the colour of eye 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 from the blood. Normal healthy goats have dark pink to red mucous membranes. Goats suffering from anaemia, which can occur with barber’s pole worm (Haemonchus contortus) 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 roundworms do not cause anaemia, however liver fluke do. There are other causes of anaemia such as cobalt or copper deficiency. A WormTest will help when diagnosing the cause of anaemia. 

FAMACHA©

Checking the colour of the inside of the lower inner eyelid has been standardized into a test for worms in South Africa, called the FAMACHA© Test. It uses a special card with different shades of pink and red and a standard method for comparing the eye mucous membrane colour. It is widely used in goats in South Africa and in the U.S.A. Goat farmers must receive training in this system before they can purchase these laminated coloured cards.

Goats are yarded and every individual is tested and recorded each 1–2 weeks during the worm season. This may not be practical if goat herds are very large, but is very useful in smaller goat herds. The FAMACHA© card allows goats to be given a score from 1 (red mucous membranes) to 5 (white mucous membranes). Goats are less likely than sheep to be scored as a 1. Only those goats with high scores (5, 4 or sometimes 3) are drenched for Haemonchus contortus worms.

By only drenching goats with high FAMACHA scores (a higher worm burden) and not drenching goats with low scores of 1 or 2, worm larvae derived from goats not exposed to drench will be left to develop on the pastures and drench resistance development will be delayed.

By recording the FAMACHA© scores, it is also possible to cull goats that are less resilient to Haemonchus contortus worm burdens and require more frequent drenching.

The 100 m walk test

Also called the “bike” or “dog” test, walking the goat herd over 100 metres and seeing whether some are lagging (a tail in the herd), or whether some collapse, is a very crude indicator of exercise intolerance in goats affected by a worm infection. If lagging or collapse are evident—and it is due to worms, and not some other cause—goats are already suffering from production loss that has generally warranted earlier drenching. If a few goats do lag or collapse when being mustered, individuals can be treated for worms, but the herd should also be sampled for a WormTest  to see if drenching should be done now. In many herds, if the tail is collapsing on exercise, then deaths due to worms are highly likely as well, resulting in an animal welfare issue.

A suitable program of WormTests is more cost-effective, and can be found in your Worm Control Program. 

Assessing scour worm infection

Weighing and condition 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.

Regular weighing or condition scoring of animals either on a herd basis or as 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. Early lactation can also cause weight and condition loss.

Condition scoring of goats is slightly different between dairy goats and fibre/meat goat breeds. This is best demonstrated by these videos:

A WormTest is more accurate, less labour-intensive, and a less stressful (to the goats) method to monitor the worm burden of a goat herd; however, observed weight loss can be a useful trigger to carry out a WormTest

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. Also, when goats have poor nutrition or another illness, they are more likely to pick up high worm burdens.

When any of these signs are apparent, a WormTest of the herd may be appropriate. If only a small number of goats are showing signs it may be useful to treat these individually while awaiting your WormTest  results. If more than 2% of the herd are showing signs, it may be appropriate to drench the whole herd. The Drench Decision Guide for your region will provide a recommendation on whether to drench or to test.