When to Drench and When to WormTest for Goats – Western Australia

Why check worm burdens in goats?

Checking worm burdens with a WormTest is essential for correct and timely drenching decisions and to confirm that your worm control program is on track. The result is healthy goats, without unnecessary drenching. 

WormTests are the best basis for drenching decisions:

• To confirm whether signs of ill-health are likely to be due to worms. Many signs are not specific to worms, e.g. weight loss and poor growth rates, a weaker tail group lagging behind the others, scouring and possibly deaths. These signs occur well after production losses from worms are occurring in the herd.
• To check whether worm burdens are causing production loss, even though signs of worms are not present. Reduced weight gains and fibre growth occur well before signs of ill-health are seen.
• To show whether the number of worm eggs being passed onto pasture is too high for a particular time of year.
• To give early warning to prevent significant production losses (or where barber’s pole worm exists, the risk of deaths).

Drenching based on WormTests is also the most cost-effective ongoing option for worm control in this region, as unnecessary drenching is expensive in both drench and labour costs, and contributes to the development of drench resistance.

How are worm burdens tested?

1.   Using a WormTest

• 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.
• Worm egg counts (but usually not larval cultures) can be done by producers if they have the equipment and skills. Ideally, producers should have their preparation and counting technique reviewed by an accredited laboratory and perform ongoing quality control checks, just like an accredited laboratory to ensure their results are correct.
• Seek professional advice where worm egg count results are not simple to interpret.

2.   Checking on farm

Where it is not practical to conduct WormTests, FAMACHA^© (for barber’s pole worm only), Body Condition Scoring (BCS) and scouring can be used to indicate if treatment is required.

• For FAMACHA^©, check the conjunctiva (inside the lower eyelid). Normal healthy goats have a dark pink to red conjunctiva. Goats 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. The FAMACHA^© scoring system evaluates the level of anaemia in the individual animal. 
• For BCS, check the back region—use the lumbar vertebra for condition scoring in meat goats. A condition score of 2.5–3.0 is desirable, while a score of 2.0 is too low, and above a score of 3.5 is too high. Does need to be in condition score 3.0 at kidding.
• Scouring. The consistency of faeces can indicate the need for treatment, however, there are other common causes of scouring. Look for watery (score 5) diarrhoea.

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When using anthelmintic products in goats, a veterinary prescription is often required because:  –Goats require a different dose rate and withholding period than specified on most products, even for many registered goat drenches. –Most sheep drenches are not registered for use in goats. While cattle drenches can be used at the label rates on goats in South Australia and sheep drenches on goats in Victoria, a veterinary prescription is still required for dose rates recommended for goats.

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When should WormTests and drenches be routinely done?

WormTests can be done at any time; however there are certain routine times to WormTest, shown below. Use the results with the Drench Decision Guide to decide whether to drench and when other WormTests should be done. A larval culture (larval differentiation) with the WormTest is particularly useful in areas or seasons in which summer rainfall occurs and barber’s pole worm is a risk.

Routine WormTest times

The South-West Medium to High Rainfall Zone

• Weaners, 6 weeks after their weaning drench, unless a summer drench is to be given at about that time
• Young goats
  • 6 weeks after the season’s break, or by the end of June at the latest, then 6 weekly to the end of spring.
  • 6 weekly after any drench is given in winter or spring (unless a drench is to be given at about that time).
• Late-kidding does (kidding later than mid-June) WormTest 3 weeks before kidding is due to start. In early-kidding does, the March-April drench removes the need for a specific pre-kid test or treatment.

Low Rainfall Cereal Zone

• Adult goats in late March-April
  Check whether a drench is necessary (testing for a couple of years will indicate the need for a routine drench).
• Bucks: WormTest at 6–8 week intervals after a short-acting drench and ensure a WormTest occurs one month before joining
• If DrenchTest results are not available conduct a DrenchCheck 14 days after treatment.

WormTest more often in high rainfall years and less often in very dry years.

Routine drench times

Some drenches are ‘strategic’, and are given for either of two purposes.

• At a critical time to reduce worm larval contamination of a pasture for the benefit of the whole mob or herd rather than just for the treated animals.
• Irrespective of worm egg count at times when goats are expected to be more susceptible to worm infection.

In WA, drenches for adult goats are delayed until autumn*, and only weaners and slightly older goats are drenched in summer. Most adult goats have low worm egg counts in early summer and a drench at that time is not warranted; delaying a drench until late March or April allows some less-resistant worms to survive.

*This practice was developed for sheep but the basic principles underlying its benefits of controlling worm infections while slowing development of drench resistance are likely to remain the same for goats but its effectiveness in goats has not been established.

The South-West Medium to High Rainfall Zone

• Kids at weaning
• Weaners and young goats including maiden does in early summer, after the pasture has dried off (this can often be done as the kids go onto crop stubble)
  Note: if weaning occurs when the kids are on dry pasture or are to be placed onto a crop stubble, the weaning and summer drench coincide and only a single drench is needed.
• Adult goats in autumn, between the end of March and the end of April
• In barber’s pole worm areas, a long-acting drench should be considered for does kidding in May or June.

Low Rainfall Cereal Zone

• Kids, and kids at weaning when are moved onto a crop stubble if this is within a few weeks of weaning. Weaned kids are highly susceptible to worms, especially from the stress of weaning. Summer weaning also coincides with high worm-risk weather conditions. Drenching at weaning will help weaners to achieve the growth rates needed for survival.
• Young goats in early summer, unless WormTests over some years indicates there is rarely a need

In all 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 or single active drenches can be used sequentially, i.e. up the race with one drench and then up the race with the other. After these drenches, move the goats into prepared low worm-risk paddocks (Drench groups and actives).

When are other WormTests done and drenches given?

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 goats and pastures.

In WA, worm control can be made more efficient using WormTests over a couple of years to determine whether a routine drench or a WormTest will be appropriate at a particular time of year. Examples are:

• Does in early summer and mid-autumn in the Medium-High Rainfall Zone: where a summer drench is not justified, but an autumn drench is usually needed. There may be variations to this pattern.
• Pre-kidding drenches for does: often given routinely, but in fact are not always necessary.
• Drenches to weaners after weaning in the Low Rainfall Zone: in drier areas, these may not be warranted.

If drenching is done for other reasons (such as an early drench before holidays or harvesting), use the Drench Decision Guide to decide when to drench or WormTest again.

What samples should be collected for WormTests?

Goats do not need to be yarded for a WormTest. Collect warm fresh dung from the paddock (but make sure that doe and kid samples are not mixed).

To conduct a WormTest obtain WormTest kits or sample collection details from your testing laboratory or advisor.

If you do your own worm egg counts, use the bulk sampling method where dung is collected into a single container.

• Collect 3 pellets per pile of dung from at least 20 individuals.
• Choose pellets of equal size so that each goat is equally represented.
• If dung consistency is runny, use a plastic spoon. Don’t avoid runny or soft dung.
• Collect kid and doe samples separately.

Avoid delays in transit (when worm eggs can hatch) by collecting and posting early in the week. Also ensure samples are kept cool (refrigerate but do not freeze) before sending, include an ice brick in transit in very hot weather and exclude as much air from the sample bags as possible.

Checking a mob of sheep or herd of goats for worms with a WormTest

Checking a mob of sheep or herd of goats for worms without a WormTest

The WormBoss Drench Decision Guide

The Drench Decision Guide helps to simplify decisions on whether and when to drench. There is a version of the Drench Decision Guide for each WormBoss region.

It considers:

• whether signs of worms are present
• the class of animal
• the WormTest results
• the condition of the animals
• the condition of the pasture
• the likely worm contamination of the paddock

The Drench Decision Guide will recommend:

• whether to drench now
• whether to use a persistent drench
• when to WormTest again

How to use the Drench Decision Guide

You can use the Drench Decision Guide at any time, whether you are contemplating drenching now or in coming weeks. Not all situations require a WormTest: the Drench Decision Guide will recommend when these should be done.

Each Drench Decision Guide is available as a separate 2-page printable version, or can be used directly online. Both are available at the link below.

Using the print version:

1. Start on the page that shows the ‘Drench Decision Guide Questions’.
2. Read Question 1.
3. Follow the ‘go to’ information on the right for the answer that applies to your sheep.
4. Only go to the question or recommendation to which you are directed by your answer.
5. When you are directed to a letter, this is the final recommendation, and is shown on the next ‘Recommendations’ page.
6. Also, read the important information in the green boxes.

Using the web version:

1. Agree to the terms of use and press start
2. Select an answer for the first question and you will automatically be taken to the next appropriate question.
3. Select an answer for each question and you will automatically be taken to the Recommendation, where your choices with also be shown as well as other important information.

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