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New South Wales worms, flies and lice update - September 2020

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Condobolin: Georgia Grimmond, DV ( and Hanna Dobell, DV (

Beware barber’s pole

With the weather warming up and the current wet forecast for spring, producers should be thinking about barber’s pole worm.

Producers need to look out for weak sheep with pale inner eyelids and gums. Sheep do not scour with barber’s pole as they do with other worm burdens; often the first sign is sheep dying.

Female barber’s pole worms lay large numbers of eggs, often up to 10,000 eggs per day. A rapid population explosion is likely when weather conditions favour it.

Barber’s pole worm infestations can be detected by worm egg counts and post-mortem of affected sheep.

Coonamble: Jillian Kelly, DV (

Worms in the Coonamble district—some people have them, some people don't. One mob of weaners had an egg count of 4,500 eggs per gram (epg) (94% barber’s pole worm and 6% black scour worm) on one farm, while mobs of ewes on a nearby farm had an egg count of 160 epg (38% barber’s pole worm, 59% black scour worm and 3% brown stomach worm). Unless you WormTest, you won't know which category you fall in—the wormy or the not so wormy. 

I am urging people to get organised and set their livestock up for a stress-free harvest. It is a nightmare to get caught mid-harvest with sheep affected by barber’s pole worm, blowflies or grass seeds, so plan ahead and get organised early.

There is blowfly activity in the district with struck sheep seen. The FlyBoss Decision Support tools are very useful to develop a fly management plan that takes into account all different strategies, rather than just heavy reliance on the application of chemicals. There are great new products that have come onto the market recently that do a good job of targeting both lice and flies. It's important to remember that we don't want to rely heavily on these sorts of products for fly control, or ruin their lice control capability over time (and vice versa). So have a good think before applying chemicals to your sheep this spring and summer.

Dubbo: Sarah Maher, DV (

With warm weather and continued moisture (with more rain predicted) it is perfect conditions for barber's pole. Producers need to be doing WormTests and using effective drenches. Many people are starting to mark lambs; this is a great time to get a WormTest done so that ewes can be drenched if needed. Producers should always select the 'Gold' option whenever possible as this gives a larval culture: an overview of the percentage of barber’s pole, brown stomach and black scour worm present.

We have had many producers in the area purchase sheep as they restock post-drought. It is really important to perform quarantine drenching on arrival to limit the introduction of resistant worms. WormBoss has a great resource on quarantine drenching found here.

Forbes: Nik Cronin, DV ( and Belinda Edmonstone, DV (

Nyngan: Kelly Wood, DV (

With many producers coming up to weaning and predicted above-average rainfall, it’s time to start thinking about how we are going to get our most vulnerable sheep through the barber’s pole season. Before you just reach for the long acting moxidectin, consider the fact that during the last round of drench trials pre-drought, 50% of properties in the Central West reported resistance to moxidectin and abamectin. Additionally, with many producers restocking after the drought, farmers may be buying new resistance genes onto their property. To give our weaners the best chance this spring and summer and to slow the development of resistant worms for seasons to come, we are going to have to be strategic and vigilant.

If you are considering using a long-acting drench this weaning, a ‘primer’ drench should be considered essential as well. A primer drench should be an effective short-acting treatment with a different active ingredient to the long-acting drench. For barber’s pole, the drench of choice would contain one of the new actives, either monepantel or derquantel. This gets rid of any existing worms in the weaners that are resistant to the long-acting drench ingredients.

Following a long-acting drench, it is important to do a WormTest with larval culture (Gold) to see how effective the drench has been. If you have a recent DrenchTest that suggests the active ingredient should be effective, you should WormTest 60- and 90-days post-drench. If you haven’t done a DrenchTest and don’t know the most effective drenches for your property, it is recommended that you do a WormTest 2–3 weeks after drenching as well, to make sure that you don’t end up with a barber’s pole crisis on your hands while you think you are protected. If the eggs per gram (epg) at any of these time points is greater than 100, it’s likely that there is some resistance to the long-acting drench ingredients on your property. In this case, drench your weaners with an effective short-acting drench (ideally a combination product) and contact your local district vet to discuss a drenching plan going forward. If the epg is less than 100 at day 90, it is still important that you provide a “tail-cutter” drench (an effective short-acting drench) at 100-days post-drenching to prevent any worms in your weaners from developing resistance as the long-acting drench begins to wear off.

Adding these simple drenching strategies to your annual management calendar can make a big difference to the success of your drenches this barber’s pole season and will preserve effective drenches for your mob for years to come. If you are interested in doing a DrenchTest and haven’t drenched your weaners yet, please contact your local district vet to discuss.

Northern Tablelands LLS

Armidale: Amanda Walker, DV (, and

Inverell: Andrew Biddle, DV (, and

Glen Innes: Nigel Brown, DV (, and

Tenterfield: Lisa Martin, DV (

Spring on the Northern Tablelands is still mixed. Our northern area around Tenterfield and the border areas are still drought-affected and producers continue to supplementary feed stock.

Areas to the west around Inverell and Delungra look promising but are looking for the next rain event.

Worms are yet to cause any significant clinical disease based on our investigations.

Our messaging is to monitor early and frequently.

Follow treatments and monitor to check drenches are working.

Spring fluke drenches are now due or a little overdue in those areas impacted by liver fluke.

Local livestock producers should be looking to ensure their young stock are effectively protected against clostridial diseases with two vaccinations 4–6 weeks apart. If you are buying stock and you are not confident of their vaccination history, assume they have never been vaccinated and start a program from scratch.

It is also a good time to ensure your blowfly program is on track with an off-shears preventative. Check FlyBoss for recommendations.

Murray LLS

Albury: Mark Corrigan, DV ( and Eve Hall, DV (, and

Deniliquin: Linda Searle, DV (

Over the last few months, District Vets in the region have investigated numerous cases of scours in sheep. In several instances, high worm burdens were found to be the main issue, however, in a few cases, the scour and associated losses were found to be due to other causes, including Yersiniosis, a bacterial infection affecting the gut.

Producers in the Murray region are advised to look out for scours and investigate the cause.  Whilst worms are the most common cause of scour in sheep, there are a number of other causes that should be considered, especially where WormTests indicate low or no worm burden or there is a lack of improvement with drenching.

Begin with a WormTest, if the counts are moderate to high, then worms are likely the primary issue and sheep should be drenched and managed appropriately. If egg counts are low or zero, other possible causes may include:

  • Other parasites: Coccidiosis is usually associated with young sheep in stressful or crowded situations and, particularly, in wet muddy conditions. Coccidia counts may be high on WormTest results. Sheep generally improve when moved onto a cleaner environment and treatment with a sulpha drench is rarely required.
  • Bacterial infections:
    • Yersiniosis, also known as ‘winter scours’, usually affects younger sheep 5–12 months of age. Stress (e.g. weaning) is often a predisposing factor and cold wet winter conditions seem to play a role.
    • Campylobacteriosis, also known as ‘weaner colitis’, occurs similarly to Yersiniosis.
    • Ovine Johnes Disease is another bacterial infection that can cause diarrhoea and wasting in adult sheep during the end-stages of the disease.
    • Salmonella infection can also result in diarrhoea, but is usually associated with other signs of disease such as fever and inappetence.
  • Nutritional issues:
    • Insufficient roughage or a diet too high in lush green feed can lead to a ‘nutritional scour’.
    • Access to grain and a poorly adapted rumen may also cause scour.
  • Hypersensitivity scour : This is an allergic-type reaction of the gut to incoming worm larvae. It can occur in adult or young adult sheep that have a primed immune system from previous worm exposure. Hypersensitivity scouring usually occurs following a relatively worm-free period (i.e. summer and autumn) after re-exposure to worm larvae, even at relatively low larvae levels. Scouring generally lasts for only 4–6 weeks. It is poorly understood, and diagnosis involves ruling out all other causes of scour.

For a more detailed synopsis of scours in sheep there is a great presentation from the 2018 ParaBoss Conference that is well worth a watch.

There have also been a lot of reports of flystrike all through the winter, which is unusual. This has included previously unseen issues in goats and freshly-mulesed lambs. Producers are advised to work out a flystrike management plan (see FlyBoss tool) now, before the flies get worse.

South East LLS

Alexandra Stephens, DV (

The worm egg count (WEC results) from the DPI lab this month have shown some higher counts due to a large proportion of barber’s pole worm, and larval cultures have shown barber’s pole to be present, even in some of the lower counts.

Barber’s pole worm loves warm and wet conditions, especially when grass is short and green. It causes anaemia and death and has a short life cycle, so problems can escalate quickly. To manage this worm it is very important to do more frequent WECs (at least every 6 weeks), especially at this time of the year to monitor for problems; to drench effectively and/or use an effective long-acting product.

It is also important to monitor for anaemia, which may be seen as weakness or pale gums, and to note that anaemia can be caused by other diseases that can be diagnosed by your vet, such as Mycoplasma ovis (a blood-borne parasite), fluke or deficiencies.

There have been many positive fluke tests in cattle, both pooled ELISA blood results and faecal sedimentation tests. If fluke is present on your property and cattle have not been drenched for fluke during the winter, a drench early in the spring is a good idea to control parasite numbers.

There have been a higher number of WECs in goats this month and all have indicated a requirement for drenching. Goats are natural browsers of shrubs and have less natural resilience to worms, so if they have been grazing closer to the ground they may now have a high worm burden. Note that they have a higher metabolic rate to sheep and that you should talk to your veterinarian about altering drench dose rates to ensure goats are effectively treated.

Western LLS

Buronga: Trent McCarthy, DV (

Recent rain events and associated pasture growth have brought much needed relief to large areas of the Western district. After several years of poor conditions for worm larvae survival, producers need to be mindful of the potential for worm burden with changed environmental conditions.  

It is pleasing to see some producers actively preparing for weaning by WormTesting lambs and having set aside prepared low worm-risk paddocks for weaning. Performing a WormTest is the most efficient and cost-effective method of determining whether a flock requires drenching. Monitor recently-weaned animals closely due to their low innate resistance to worms and lowered immunity due to the stressors of weaning. Follow up worm tests can be performed every 3–4 weeks if required.

It is also important to ensure these weaned animals receive their booster vaccination (generally their second vaccination following initial vaccination at marking) to help prevent losses associated with clostridial disease, such as pulpy kidney. Reducing antibody levels combined with rapidly growing green feed and the stress of weaning can result in some costly losses.  

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