When to Drench and When to WormTest for Goats – Tasmania
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.
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.
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 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. Note: a larval culture (larval differentiation) is particularly useful in areas with non-seasonal annual rainfall or where barber’s pole worm are common on the property.
Routine WormTest times
Any goats showing signs that suggest a high worm burden (e.g. scouring, anaemia, lethargy) Request a larval culture if anaemia is present or barber’s pole worms are suspected. Treat if egg count exceeds 300 epg, then WormTest again in 3–4 weeks.
6–8 weeks after the first summer drench to see if a second summer drench is warranted. Give a second summer drench:
On perennial pastures in all regions or high rainfall regions or on irrigated pastures, if egg count exceeds 100 epg.
In the summer rainfall region where does are not on perennial pastures, if egg count exceeds 500 epg.
In the low rainfall zone, if the pasture was green beyond Christmas or if WormTest results in spring were 600 epg or above.
During March to October, WormTest adult mobs each 4–6 weeks (4 weekly in the wetter months, 6 weekly in the drier months) and treat with an effective short-acting drench if egg count exceeds 300 epg. High counts (>600 epg) in April/May on goats in the paddocks to be used later for kidding indicate high pasture contamination of those paddocks and that does may require a long-acting treatment pre-kidding.
3 weeks after the weaning drench.
Just prior to a possible second summer drench (late January/early February).
Otherwise, WormTest each 3–4 weeks until 1 year old
Treat weaners in the high rainfall region if egg count exceeds 200 epg.
Treat weaners in the low to medium and summer rainfall region:
In January/February (second summer drench time) if egg count exceeds 100–150 epg.
In Autumn/Winter/Spring if egg count exceeds 300 epg.
If drenched at marking, WormTest prior to weaning, rather than giving a routine drench. Treat if egg count exceeds 200 epg.
Does in the high rainfall zone that will stay on perennial pastures, WormTest just prior to weaning. Treat these ewes at weaning only if results are 200 epg or above.
WormTest bucks about 10 weeks prior to mating. Treat with an effective short-acting drench if egg count exceeds 200 epg.
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.
All goats: weaners, does, bucks, wethers
A first summer drench in November/December as the pasture is haying off. This drench may coincide with marking or weaning.
Any animals going onto a fodder crop/perennial pasture to be used as a low worm-risk pasture for young goats in winter. If this is during preparation: “smart graze” the pasture for up to 30 days only to prevent further contamination with worms.
At marking, only if
does are scouring and in poor condition (less than condition score 2.5), in which case treat both the does and kids.
marking coincides with the first summer drench time.
At weaning, unless a drench was given at marking, in which case WormTest before weaning and treat if egg count exceeds 200 epg.
At weaning, unless they:
Are does in the high rainfall zone that will stay on perennial pastures.
Already received a drench at marking.
In either case, WormTest just prior to weaning and treat these ewes at weaning only if egg counts exceed 200 epg.
At mating, treat with an effective short-acting drench.
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).
If DrenchTest results are not available, conduct a DrenchCheck 14 days after treatment.
Note: only in very high worm-challenge years may a long-acting product (requiring an off-label veterinarian prescription, as none are registered for use in goats) be required in early winter for weaners. This will be indicated if more drenches than usual were required prior to this time and autumn/winter weaner paddocks could not be kept low worm-risk. After these drenches, move the goats into prepared low worm-risk paddocks.
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 to weigh up important factors when deciding when to drench or WormTest on your property. These factors include signs of worms, time since last drench, the persistence of the last drench, WormTest results, recent rainfall, and condition of animals and pastures/browse.
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?
Animals do not need to be yarded for a WormTest. Collect warm fresh dung from the paddock (but make sure that samples from ewes/does are not combined with those of their lambs/kids).
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 if the mob has fewer than 200 animals and at least from 40 individual dung piles from larger mobs.
Choose pellets of equal size so that each animal is equally represented.
If dung consistency is runny, use a plastic spoon. Don’t avoid runny or soft dung.
Collect ewe/does and lamb/kid 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 goats for worms with a WormTest
Checking a mob of sheep or goats for worms without a WormTest
The WormBoss Drench Decision Guide
TheDrench 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, and the link given here is for the Tasmanian one.
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:
Start on the page that shows the ‘Drench Decision Guide Questions’.
Read Question 1.
Follow the ‘go to’ information on the right for the answer that applies to your sheep.
Only go to the question or recommendation to which you are directed by your answer.
When you are directed to a letter, this is the final recommendation, and is shown on the next ‘Recommendations’ page.
Also, read the important information in the green boxes.
Using the web version:
Select an answer for the first question and you will automatically be taken to the next appropriate question.
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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