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When to WormTest and when to drench

WormBoss worm control program for goats

Qld central and south and NSW northwest


 

When to WormTest and when to drench goats

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 (Drench Decision Guides):

  • 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.

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 useful, but 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.

 

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.

Routine WormTest times

  • Before goats are in the yards for management purposes a WormTest should be considered.
  • Does
    • Pre-shearing in fibre goats (can be the pre-kidding test)
    • Prior to kidding, kid marking and weaning
  • Kids from weaning to their first kidding: WormTest at 4–6 week (summer) or 6–8 week (winter) intervals after a short-acting drench.
  • Bring forward WormTests if there has been significant rain (20+ mm) that also has follow-up rain (10+ mm) in the following few weeks.  Do separate tests for adults and weaners.
  • Bucks: WormTest at 4–6 week (summer) or 6–8 week (winter) intervals after a short-acting drench and ensure a WormTest occurs one month before joining.
  • WormTest more often in high rainfall years and less often in very dry years. However, when goats congregate on smaller areas due to tall thick pastures, heavy rain/flooding or bore drains, WormTest more frequently.
  • If DrenchTest results are not available conduct a DrenchCheck, 14 days after treatment.
  • And at other non-routine times as suggested in the Drench Decision Guide.

Check the intestines: Nodule worm can be a problem in this area; check for signs when any sheep or goats die or are killed for rations. Open the abdomen and find the large and small intestines. Examine the outside wall of each for firm white pimples or nodules. If these are present, you should routinely drench in May with a drench that contains either a macrocyclic lactone (ML) or a benzimidazole (BZ).

Routine drench times

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

  1. 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.
  2. Irrespective of worm egg count at times when goats are expected to be more susceptible to worm infection.

Use an effective registered short-acting drench and follow label instructions when treating for worms.

  • Kids at 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.
  • In October/November
    • If the grass is green and actively growing in these months: 
    • All goats should be given an effective drench for barber’s pole worm, scour worms and nodule worm. A prior WormTest will indicate whether a long-acting product could be needed i.e. if the WEC is greater than 500 epg, and seasonal conditions are good, your goats may need extra protection against barber’s pole worm, such as a mid-length or long-acting drench (if effective on your property). Note long-acting products are not registered for goats and in most states and territories can only be used “off-label” with a veterinarian’s prescription.  If a persistent product is used, the goats can be kept on the same pasture or moved elsewhere according to your management needs. If a short-acting drench is used, move the goats to low worm-risk pastures with good feed. If using a persistent drench then see ?Effective use of long-acting drenches.
    • If the grass is brown or not actively growing in these months: 
  • Young goats (less than 18 months old) will need an effective short-acting drench against barber’s pole worm, scour worms and nodule worm. WormTest in 4–6 weeks after the drench. 
  • Drench individual goats showing obvious signs of worm-related illness and WormTest the rest of the goat herd. 
  • At other times, use the results of a WormTest in the Drench Decision Guide.

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).

The use of vaccination against barber's pole worm

A vaccine to protect against barber’s pole worm is available for sheep but is not registered for use in goats. Trials using the vaccine in goats have provided variable protection indicating the vaccine may not always be effective. In sheep, the vaccine provides a major alternative to drench-based control and will help manage drench resistance. If you wish to consider its use in goats, you will need to discuss the pros and cons of its off-label use with your veterinarian and obtain an off-label prescription.