Paid Advertisement
 




Online learning: NSW northeast and Qld Granite Belt—Worm Testing

Aside from drenches at one or two strategic times the mob’s average worm egg count should be the basis for other drenching decisions.

Structured reading

For those who like to see all the information and simply read through it in order. Each heading is a link to a page of information—the dot point provides a summary of the page.

Tip: Keep this page open and open the links in new tabs.

Checking a mob of goats for worms with a WormTest
How-to guide to collect and submit samples for a mob worm test to a laboratory.

Worm egg counting
How worm egg counting is carried out.

Assessing worm burdens without a WormTest
Other ways to assess whether goats have worms and what level of worms exist.

Collecting dung samples from individual goats (optional)
How-to guide on collecting dung samples from individual goats (for drench resistance tests or genetic assessment of worm resistance).

Worm testing for stud goat breeders (optional)
How-to guide for stud goat breeders who want to gain worm egg count values for individual goats.

Question and answer

For those who prefer a problem based approach to learning, answer the following questions.
Each of the questions below links further down the page to the answers.

Questions:

  1. How many individuals should be sampled for a WormTest?
  2. Name a standard time when you should WormTest.
  3. What 2 things does a larval culture tell you and how these help you make a drenching decision?
  4. Name a situation when you would drench without a WormTest?
  5. You can use the WormTest from one mob to make drenching decisions about similar mobs. For every mob you test how many other mobs could this represent?
  6. If only very few goats (less than 2%) in a mob appear to be badly affected by worms: ? What could be a cause of this?  What action would you take? 

Answers:

You can also click on each question below to go to WormBoss pages with related information.

1. How many individuals should be sampled for a WormTest?

Collect the number of samples per mob as recommended by your laboratory (ideally this would be from at least 20 goats—if you are doing your own worm egg count on farm, try the following ‘bulk collection’ method.

Bulk collection method:

When conducting your own worm egg counts on farm:

  • Collect three pellets per adult pile (or the equivalent amount if soft or runny) or five for weaners.
  • Collect from at least 20 dung piles.
  • Where Haemonchus (barber’s pole worms) are an issue, and if there are over 200 goats, collect from each of 40 dung piles.
  • Collect all dung into one container
  • The dung then needs to be mixed extremely thoroughly.
  • Conduct your worm egg count using a sub-sample from the bulk mixture.

2. Name a standard time when you should WormTest.

WormTests can be done at any time; however there are certain routine times to WormTest (preferably with a larval culture):

  • Pre-shearing for fibre goats.
  • Pre-kid marking for does. (Generally, there is no benefit from drenching kids at kid-marking, however, if a WormTest indicates that the does need drenching, the kids should also be drenched).
  • Pre-weaning fordoes. (Not for kids as they will be drenched at weaning).
  • From weaning time, WormTest all groups of goats at 4 week (summer) or 6 week (winter) intervals after they have been given a short-acting drench. If a persistent drench is given, use the Drench Decision Guide to decide when a WormTest should be done.

3. What 2 things does a larval culture tell you and how these help you make a drenching decision?

A WormTest refers to a ‘Worm Egg Count Test’ or ‘WEC test’; it will identify the number of worm eggs in faeces, which is a good indication of the worm burden of the goat. Some laboratories can also perform a ‘Larval Culture’ (also called a ‘Larval Differentiation’) to identify the types of worms present and their proportion (the importance of this varies according to your location).

4. Name a situation when you would drench without a WormTest?

A) When giving a quarantine drench.

B) When giving a strategic drench. The timing of strategic drenches depends on the region and the class of goat, as their use is closely associated with times when goats are most susceptible to worms or  when development of eggs to infective larvae on pasture is likely to be extremely low (to reduce pasture contamination) or high (to pre-empt likely immediate problems). Strategic drenches are given regardless of the average worm egg count of the herd.

There are six common strategic drenches; not all are used in every region. The WormBoss programs outline which strategic drenches to use in each region.

  • Pre-lambing does
  • Kids being weaned
  • Winter weaners going into low worm-risk paddocks
  • Smart grazing as used in sheep
  • Summer drenches—temperate winter rainfall regions 
  • Summer-autumn drenches—Mediterranean climatic regions

Details of when/how to use strategic drenches are in Your Program.

5. You can use the WormTest from one mob or herd to make drenching decisions about similar mobs. For every mob you test how many other mobs could this represent?

Ideally each mob should be tested individually, as there are usually differences between paddocks in the favourability for worm survival, the number of worm eggs being deposited by different mobs, and the time since a drench was given. However, if there are a number of mobs that have the same drenching history, same class of goats and very similar paddock type (including recent level of contamination from worms) then one mob can represent two others (i.e. test one in every three similar mobs).

Testing representative mobs saves the cost of testing all mobs, but carries the risk that the result may not be representative.  If in doubt, test additional mobs. Testing individual mobs is suggested for Western Australia, South Australia, Victoria and Tasmania.   

6. If only very few goats (less than 2%) in a herd appear to be badly affected by worms: What could be a cause of this? What action would you take?

If less than 2% of a herd are showing signs that include pale inside eyelids and gums, bottle jaw, lagging or collapse, you should treat these affected goats immediately with a drench suitable for barber's pole worm, but also sample and test the remainder of the herd now. If these signs are not visible, but a few goats are scouring badly, test the herd now. In both cases, use the results with your Drench Decision Guide to decide whether the whole herd should be treated.

When less than 2% of a herd show signs of worms these are the possible causes:

  • These goats were not drenched when the rest of the herd were (e.g. didn't get mustered, were missed or spat out the drench in the race, strayed in from another herd). Their worm egg count may be a lot higher than the rest of the herd.
  • These goats are suffering from some other illness or injury that has reduced their immunity and they have acquired a larger worm burden than the rest of the herd. Signs of another problem may be evident. 
  • These goats are the most susceptible in the mob because of lower worm-resistance and the herd has been tested just when these first goats are starting to show signs.
  • These goats  are not actually affected by worms at all. Instead, anaemia could be the result of liver fluke and scouring could be from coccidiosis or excess lush feed.

In all of the above situations, a WormTest on the remainder of the herd (don't include these badly affected goats) to determine the worm egg count will inform your decision of whether to treat the rest of the herd.

 


Links to the learning topics for NSW northeast and Qld Granite Belt

  1. Introduction
  2. Grazing management
  3. Breeding for worm resistance
  4. Worm testing (you are currently on this page)
  5. Drenching
  6. Drench resistance management
  7. Goat worms