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New South Wales worms, flies and lice update - January 2018

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Coonabarabran: Alix Ferguson, DV (

In our region the number of worm tests and egg counts conducted have been steadily rising. Since the start of December the Coonabarabran region has received storms and good rainfalls totalling 80-100 mm in some areas. Worm egg counts have ranged from 176 eggs per gram (epg) to 1852 epg. Most of these worm counts show a dominance of Haemonchus with larval cultures showing between 90-100% barbers pole worm.

One producer reported clinical levels of black scour worm due to grazing conditions, and a potentially ineffective drench. This highlights the importance of doing a DrenchCheck with a larval culture 14 days after the drench is administered to assess the effectiveness of the drench.

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

There have been few worm tests submitted from the Forbes area. Of these, most have shown very low worm counts. Cultures have indicated both barber's pole dominant and mixed worm burdens.

When considering whether or not to drench at this time of year, it is advised to worm test in advance. If the counts are very low then drenching would not be recommended as it may do more harm than good as more drench resistat worms can remain after any drench.

Nyngan: Erica Kennedy (

There have only been two worm tests submitted to EMAI from this area over the last month. One test had individual counts ranging from 40-1360 eggs per gram (epg) showing the variation in susceptibility and innate resistance between animals.

Local private veterinarians and local agricultural supply stores have been doing many more tests, all returning results in the low average range, and also individual counts the highest of which was around 300 epg. The low counts seen are likely a result of the hot and dry conditions we have been experiencing in the Nyngan district, however producers are reminded that hatched barber’s pole larvae can still survive temperatures between 35-40 degrees centigrade for around 4-6 weeks depending on the humidity.

Barber’s pole eggs can only survive for 5 days while waiting for suitable hatching conditions (high soil moisture profile or >10-15mm rainfall). With no rainfall recorded in Nyngan for the 4 weeks of December it is likely that few larvae developed during that time, however since the beginning of January we have been lucky enough to have received 59 mm of rain so eggs will have hatched and there will be plenty of larvae being ingested at the moment. As it takes at least 18 days for a larva to grow into an adult inside the animal and start laying eggs, the time to WormTest is NOW! If you have done a WormTest recently and had low results, it would be wise to retest 3-4 weeks after the last test was performed. 

If your WormTest returns a high number of eggs per gram of faeces (as a rough guide, around 500 epg for barber's pole) and the decision is made that a drench is required, producers are reminded to use a short acting combination drench to slow the development of resistance. Also refer to the Drench Decision Guide to determine whether drenching is warranted based on your WEC result and local conditions.


Riverina LLS

Young: Rahul Shankar, DV (

Crutching and flystrike prevention— these are still topics that arise in conversations with primary producers. This is a reminder to producers to be mindful of withholding periods when using flystrike prevention both for meat and wool depending on the type of product being used. 

Worms—worm egg count tests (WormTest) that have been submitted to the regional laboratory in Menangle have shown low to moderate worm burdens. The majority of the species have come back as black scour worm or the brown stomach wormBarber's pole worm has been reported on a few properties in lamb mobs some of which have experienced losses. Appropriate drenching has been advised for these producers, with a reminder to those that are wishing to sell lambs soon to be mindful of withholding periods and Export Slaughter Intervals (ESIs) when choosing your drench product. Please consult your local district veterinarian should you need further assistance in selecting a product appropriate for your property. 

Other issues producers should be aware of:

Grain poisoning—have you checked stubble paddocks for any grain spills prior to placing stock on them? Cases of grain poisoning have inadvertently happened on paddocks where grain spills have occurred. 

Weeds—with the rains of December and January weeds such as Hairy Panic, Heliotrope and St. Johns Wort continue to pose a risk to stock. Producers are urged to ensure that appropriate measures such as spraying paddocks and waiting for the plants to dry off, have taken before placing stock onto weed infested paddocks. 

Pneumonia—there have been a few reported cases in our region. Dusty conditions and prolonged higher day time and night time temperatures have been giving rise to cases of pneumonia. Signs to be aware of include coughing, lying down for a prolonged period of time, lingering behind the rest of the mob, and finding dead animals. 

If you are concerned about production issues on your farm(s) please contact your local District Veterinarian. 

Wagga Wagga: Timothy Biffin, DV ( and Emily Stearman, DV (

Reports from the Wagga area are very similar to the remainder of the Riverina area.

Given recent moderate increases in worm burdens as indicated by a rise in worm egg counts observed across the Wagga area, it appears as though the unseasonal summer rainfall has promoted growth of scour worm species and barber's pole worm. Always conduct a worm egg count (WormTest) on the mob before drenching at this time, but results are likely to indicate that 'summer drenching' of sheep is likely to be quite a positive action on farm from now through to approximately February. 

Generally, fly strike incidence appears to be moderate, following active preventative measures already taken on-farm. 


Northern Tablelands LLS

Inverell: Andrew Biddle, DV (

Rainfall through January has been patchy with high temperatures in the western parts of the Northern Tablelands. This variation in weather will create variations in survival of worm eggs and larval contamination of paddocks.

We recommend regular monitoring using WormTests to determine if drenching is required, or as an early warning of rising worm burdens.

If introducing new sheep to your flock remember to give a quarantine drench on arrival and keep new arrivals separate from the flock while you observe their health status.

Editor’s note: After quarantine, release sheep onto a paddock that is likely to be contaminated with worm larvae due to grazing by other sheep. This will ‘dilute’ (lower the proportion of) resistant worms surviving treatment with worm larvae already on your property. 


North West LLS

Narrabri / Walgett: Megan Davies, DV ( and Judy Ellem, DV (

In the north west of North West LLS, from Narrabri and Moree out to Walgett and Lightning Ridge, we received approximately 20 worm test results over the past month. The majority of these came from two large properties that tested each mob of sheep separately.

The importance of this can be seen in the results: on one property, all mobs tested had large worm burdens with counts of up to 2000 eggs per gram. The culture results showed that the type of worms present varied between mobs, with some mobs having 100% Haemonchus (barber’s pole worm), and others having only 20% Haemonchus. However, the majority (60%) of tests showed Trichostrongylus (black scour worm), and a few Teladorsagia (brown stomach worm) also present. This information is important when choosing which drench to use as you can more effectively target the specific species present in each mob. 

Another property at Lightning Ridge tested six different mobs, and found very low worm numbers, with counts of 0 eggs per gram in three mobs. This producer is now able to save time and money, knowing that those mobs don't need to be mustered and drenched. 

It is also worth noting that we are still seeing some high worm burdens despite the hot, dry weather—a good reminder that we cannot rely on the heat to deal with worms for us. This is particularly true when sheep are being supplementary fed, as they are either held in smaller pens or gathered in certain areas to be fed, leading to high levels of faecal contamination and high likelihood of ingesting infective worm larvae when feeding. 

If you need help interpreting your faecal worm egg counts, call your local district veterinarian. 


Murray LLS

Deniliquin: Scott Ison, DV ( and Linda Searle, DV (, and

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


In the west of the region we have not had any call outs to worm infected sheep. However, we have had one Wormtest result for lambing ewes with an unknown worming history in good condition with no signs of scouring. The results came back with an average of 1840 eggs per gram (epg) strongyle type, which on culture, was found to be mostly barber’s pole worm (92% of the sample), with 4% each, of black scour worm and brown stomach worm.

While the West of the region does not usually have large issues with barber’s pole worm they can occur as a result of sporadic summer rain events. Unlike our usual scour worm, barber’s pole worm is a blood feeding worm so sheep will not scour when affected. Instead sheep will have pale membranes in their eyes and gums, they may have bottle jaw, which looks like a big fluid swelling under the jaw, and possibly go down when you try to move them. There have been widespread reports of drench resistance in barber’s pole worm. This means that a combination drench that contains more than one active ingredient may be indicated. It is also a good idea to use a combination drench as your quarantine drench when new stock is brought onto your property to try and stop a resistant worm population establishing.

{Editor’s note: Combination drenches have a greater chance of being effective than their single active ingredients, however, do not assume that just because it is a combination it is effective, especially on barber’s pole worm, and particularly in sheep brought in from summer rainfall areas. A recent test done in a WormBoss Producer Demonstration Site project (in Northern NSW) had results with a combination of 4 older actives below 50% effectiveness. Always include one of the newer actives (found in Startect or Zolvix or Zolvix Plus) in a quarantine drench along with 3 other actives. Two separate products may need to be given (not mixed together).}


EMAI laboratory WormTest submissions have been limited in the eastern region this past month. One local producer suffered significant losses in a mob of scouring and dying Merino lambs.

The investigation suggested worms were responsible and WormTest results showed average counts of 720 eggs per gram (epg) strongyle type eggs and 80 epg Nematodirus type eggs. Larval culture showed the strongyle breakdown to be 67% black scour worm and 33% brown stomach worm. In this case it was suspected that grazing of a possibly contaminated pasture in combination with untimely rain was likely to have been to blame. A good response was observed following treatment with a triple combination drench containing abamectin, oxfendazole and levamisole. A follow up DrenchCheck will be performed. It is interesting to note that one individual showed a Nematodirus egg count of 440 epg (along with a strongyle egg count of 1680 epg), indicating that secondary Nematodiasis (disease due to the presence of immature Nematodirus spp. in the small intestine) may have played a role in this lamb’s demise.


South East LLS

Goulburn: Bill Johnson, DV (

High worm egg counts, sheep that flop down and won't travel when mustering, sheep with very pale skin and eye mebranes, and lambs with swollen heads—these are just a few of the signs producers found when their sheep were affected by barber's pole worm (Haemonchus) since New Year. Some producers are surprised to know barber's pole worm is still active, as conditions have been pretty hot and dry lately. Hot-spots for worm larvae remain in many paddocks after late spring rain, especially low-lying parts of the paddock which are still green. And drench resistance is part of the problem in other cases, with recently used drenches not removing existing infection, or long-acting treatments failing to stop re-infection.

{Editor’s note: Remembering that worm larvae take months to die, these sheep may have also been picking up barber’s pole worm larvae for some months and it is only recently that they have reached a clinical level.}

But just to confuse things, there can be other explanations for each of these "it must be barber's pole" signs. One producer recently tested two mobs of ewes, split just prior to spring lambing into single and twin-bearing mobs. Both mobs now have reasonably high worm egg counts (in the thousands), with one mob 100% barber's pole, and the other 100% scour worms. So not all high worm egg counts are barber's pole.

We've also had a few cases of "infectious anaemia" (also called Eperythrozoonosis or “Epi”) in lambs due to a blood parasite called Mycoplasma ovis, six to eight weeks after marking. Affected lambs are extremely pale and can't handle any exercise.

Heads swollen from barber's pole worm have a build-up of fluid under the jaw and in the lips and muzzle. We've seen other lambs and sheep with swollen heads, including droopy eyelids and ears, from photosensitization.

Blowflies continue to strike sheep with wet dags. Several producers still rely on diazinon-based products to treat blowfly strike, despite research that shows widespread resistance. The ParaBoss website has details of more effective treatments, especially where older maggots are present.

NSW DPI is keen to obtain maggot samples from fly-struck sheep, as part of an AWI-funded project looking at chemical resistance. Maggots will be tested against a range of commonly used chemicals, with results available to participants. It is a great opportunity for you to find out what chemicals work best for blowfly prevention and treatment in your flock. The researchers are also keen to test samples of sheep lice for chemical resistance. Contact your LLS district veterinarian for help with sample submission.

Yass: Fiona Kelk, DV (

Sporadic summer rains with warm to hot conditions have encouraged Haemonchus (barber’s pole worm). It is imperative to monitor your stock. Better yet, conduct a (WormTest) so you can be informed of the size of the parasitic burden in your sheep.


Greater Sydney LLS

Penrith: Nigel Gillan, DV (

Very few WormTests have been performed by producers in the Greater Sydney region in recent weeks.  Rainfall has been slightly below average for most areas in the past few months, but Haemonchus (barber's pole worm) continues to be a risk for sheep and goat producers.


Western LLS

Bourke: Charlotte Cavanagh, DV (,

Balranald : Hannah Williams, DV ( and  

Broken Hill: Felicity Wills, DV (

Conditions are hot and dry. Worm eggs and larvae are not surviving on pasture. Results of the one WormTest conducted was zero eggs per gram.

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