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New South Wales worms, flies and lice update - October 2017

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Armidale: Stephen Love, Veterinarian/Research Officer (Parasitology) (

After 6 months or so of below average rain for most of NSW, the first half of October has seen good, and even heavy fails of rain in parts of the state, notably the northeast and parts of central and southern NSW. Pastures in these areas have had a new lease of life 'overnight', which means worms have too, especially if there are good ‘follow-up’ rains.

Of the important roundworms of sheep, the one that will respond most quickly to recent rain, now that day time temperatures are commonly over 18 degrees Celsius, is our old 'fecund' friend, Haemonchus contortus—barber's pole worm (BPW).  BPW will increase even faster in numbers if it had a good launching pad coming out of winter, i.e. there were plenty of BPW larvae on pasture, going into winter, surviving winter, and now are ready to respond to the favourable weather conditions.  Common reasons for large numbers of larvae on pastures at the end of winter would include: not using effective drenches, not drenching when required, which in turn may be due to infrequent or zero worm testing (worm egg count monitoring using WormTest), and not preparing low worm-risk paddocks for ewes lambing in spring. Other factors include nutrition and the genetic makeup of the flock. 

What are the two most important things you can do to manage worms?

1. Read and follow Your Program (the program for your region) in WormBoss.

2. Do regular WormTests (which is included in [1]).  In most areas at this time, WormTest a number of representative ('sentinel') mobs every 4 weeks.

If you do nothing else, do regular WormTests. See it as an investment, not a cost, in time or dollars. Worm testing includes doing egg counts 14 days after drenching, i.e., DrenchChecks. Drench resistance is very common, and without testing NO-ONE in Australia can be 100% certain that ANY drench on the market will be highly effective on their property.


Central West LLS

Coonabarabran: Alix Ferguson, DV (

Our area has received varying falls of rain in the range of 5–20mm (depending on location) in the past week.  This is much needed rainfall, and combined with some warmer temperatures, hopefully, will kick off some much needed pasture growth.

Thinking and planning ahead; do you have a low worm risk paddock available for summer weaning? This can be achieved over 3 months by spelling, grazing with cattle, or with sheep that are within the protection period of their (effective) drench. A drench test with larval culture is recommended pre-weaning so that you have the knowledge to choose the most effective drench for your weaners.

The table below shows a sample of the results of WormTests carried out in our region over the past month, the predominant worm on larval culture being Haemonchus or barber’s pole worm.

Table 1. Worm Test results for the Coonabarabran area, October 2017

Mean (epg)

Range (epg)

Trichostrongylus (%)
black scour  

Teladorsagia (%)
brown stomach

Haemonchus (%) barber’s pole




















































































Coonamble: Jillian Kelly, DV (

Very few worm tests (WormTest) from the Coonamble area were submitted to EMAI in the past month.  The few that were, have shown low worm burdens of mixed species.  The district has experienced two decent falls of rain in recent weeks, which may cause worm burdens to increase over the coming weeks. Producers are advised to worm test.  This rain has also seen blowfly numbers increase. Producers need to be mindful of this and ensure sheep are treated to prevent strike.

Nyngan: Erica Kennedy DV (

In the last week, after months of extremely dry conditions and shortening feed length, we have finally had some decent rain. Rough totals over the week range from 35–70mm. Daytime temperatures are now optimal for worm larval development on pasture, and with the current short length of feed in many paddocks and the green pick that's sure to sprout, the likelihood of a surge in worm burdens is very high. Despite only one worm test through EMAI for the region since September, the recent general consensus is that egg counts have been low and of mixed species. 

All producers should be performing WormTests in the next 2–3 weeks. Due to the favourable conditions it is imperative that a larval culture is performed to identify the types of worms present so that an effective drench can be used if required. 

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

Worm egg counts after the particularly dry winter in our area are expected to be very low, and results from most samples submitted have confirmed this. However, the odd test has yielded a significant result. In addition, one producer reported losses in ewes at shearing with 'white gums', and sporadic bottle jaw in the mob suggesting barber's pole. To avoid this we recommended using WormTests to monitor any build-up in worm burdens. As the season continues to dry off, worm tests should be used to determine whether the first summer drench is necessary. If counts are low then this drench may not be required. Drenching in this situation may actually cause increased selection for drench resistance.  

Riverina LLS

Young: Elizabeth Braddon, DV ( and Rahul Shankar, DV (

The northern part of the Riverina LLS (i.e. Young - Ungarie) has received some rainfall in the last month that will promote some level of worm activity now that the weather is warmer. It will be important for producers to drench their weaners to ensure that optimal production targets are met as they are most susceptible to even moderate worm burdens.  

‘How do I tell if my sheep are wormy?’ a question a producer may ask.  Producers should consider performing a very simple, but effective test—the worm egg count test (WormTest) based on 'poo' samples collected from the sheep/mob.  For more information on obtaining a test kit or how to do this, contact your local veterinary advisor or district veterinarian.  For a fairly simple financial outlay, the gain can be substantial in terms of lower treatment costs or even better, prevention of lost production or deaths depending on burdens.

Gundagai: Kristy Stone, DV (

There have been recent rainfall events in the region in combination with warm weather, so I would expect that larval development on pastures will be on the rise. Producers should be thinking about worm egg testing (WormTest) if they haven’t already, to determine if they need to drench

This month in the Gundagai area WormTest submissions were low. One property had an average count of 552 strongyle type eggs in pre-weaning lambs. Larval differentiation indicated 100% Haemonchus

Narrandera: Sophie Hemley, DV (

The Narrandera–Griffith area has had some rainfall over the last few weeks. Similar to the Northern Riverina area, warmer daily temperatures will promote optimal conditions for worm survival. A worm egg count (WormTest) is recommended for all highly susceptible mobs—such as young or feedlot stock. 


Northern Tablelands LLS

Glen Innes: Nigel Brown, DV (

At last, some rain and pasture growth. These conditions are unfortunately also optimal for worm eggs to hatch rapidly and the resultant worm larvae to survive on pasture.

Already there have been some seriously high Haemonchus (barber’s pole worm) results. Drench resistance is evident again this year with some people not doing any simple testing (DrenchCheck). One producer had a major failure of his pre-lambing drench that led to sick/dying ewes in the mob—some with lambs at foot, and others yet to lamb—a husbandry nightmare. From the ten samples submitted, two had 0 eggs per gram (epg) and the others up to 20,000 epg with an average of 6,000 epg.

Resistance issues aren't going to go away, so it is certainly well worth doing post-drenching tests (DrenchCheck) to ensure you are using effective drugs at critical times.

Learning to do simple faecal worm egg counts yourself will soon pay for the cost of equipment—and there are a range of training courses, such as Tocal and NTLLS in this part of the world. Equipment cost is less than $500 and ongoing costs are minimal—little more than salt and water.

There was a suspected case of lungworm in coughing sheep. No larvae were detected in the faecal filtration test, and the case responded to antibiotics. Lungworm aren't usually a sheep problem, but they can be in horses (though a different species to those in sheep and goats), donkeys are a notorious source of infestation for horses. 


North West LLS

Northern Slopes: Ted Irwin, DV (

Current environmental conditions are good for the development and survival of all types of worms.  There haven’t been any worm egg count results or cases of clinical disease to report, except for an investigation into the cause of dying lambs near Duri (Tamworth). While worm egg counts were high (3,000 eggs per gram (epg) in one dead lamb, the case was complicated by Polioencephalomalacia (PEM)  from eating brassicas. Unfortunately, laboratory analysis did not recover enough larvae from the sample (their count was only 980 epg on the same sample) to complete a larval differentiation. These lambs had been drenched with Nilverm 6 weeks earlier. It would have been interesting to know the size of the scour worm population following the Nilverm treatment to gain some information on the efficacy of this drench against these worms.

Lambing is now out of the way, and as these resultant lambs will soon be reaching the age of maximum susceptibility to worms, it will be interesting to see if any clinical cases emerge in the later part of spring. 

Moree: Justine McNally, DV (

I noticed in the September WormTest results that we are still seeing black scour, brown stomach and barber’s pole worms fairly evenly distributed on all places especially the north west of Moree (but these producers are the ones always sending in WormTests—good work!).

My big worry going forward into this spring and summer is a barber’s pole worm invasion.  Stock have been hand fed since about March—so there are lots of sheep in small areas, pooing a lot, lambing, lactating and under some nutritional stress—thus potentially producing large numbers of worm eggs over time and contaminating pastures, AND NOW rain and warmer weather are in the mix.  We have had upwards of 100 mm in a lot of areas in the district and there is short, green pick, but hand feeding is continuing and there are mixed mobs of ewes and lambs.  Most will wean around December due to harvest commitments (if they have a crop) or planting a summer crop (if they got the rain). 

This means that checking sheep and drenching if necessary, could go out the window as producers become busy elsewhere, so come December, January and February I can see potential losses from barber’s pole infections.

I have emailed my sheep producers a few times in the last 3 weeks trying to encourage them to do WormTests every 4 weeks over the summer.  I also suggested pushing mobs a little and then checking any stragglers for pale mucous membranes or bottlejaw.  Producers were also advised to move feeders to paddocks with less faecal contamination, and to continue worm testing and drenching if necessary, with follow-up checks (DrenchCheck) post drenching.

People seem to be using Avomec Duel and Triguard.  One DrenchCheck—a little late at 20 days after drenching (should have been 14 days)—identified one very good result and one not so good result.  There may be some resistance, and that mob may need to be drenched again with a triple or quadruple drench.

(Ed: As Justine mentions, these follow-up tests were too late. Barber’s pole worms can be laying eggs by 18 days after infection so a WormTest at 20 days post-drenching should not be used to indicate drench efficacy.)

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

Around Narrabri we've only had a handful of producers testing for worms (WormTest) over the past few months. Of those, many have come back with significant worm burdens, with egg counts of over 2,000 eggs per gram (epg). On culture, the results have been varied—some properties showing 100% barber’s pole (Haemonchus) infections, while others have 50% barber’s pole and 50% black scour worm (Trichostrongylus). The brown stomach (Teladorsagia) worm has shown up in very low numbers only on one property.

Most properties now have lambs on the ground, and with scattered rainfall leading to patchy green pick following the prolonged dry, many producers are considering early weaning. It is important going forward to manage the worm burdens in these lambs to prevent deaths and improve growth rates. Contamination of high traffic pasture areas around feed troughs with worm eggs is likely, and when the sheep pick at the small green feed they will readily ingest these eggs. 

Remember to worm test regularly, request cultures so that you know what species you are dealing with, and use the most effective drench, or combination of drenches to target the worm species involved. 

Murray LLS

Albury: Scott Ison, DV ( and Mark Corrigan, DV ( and

Deniliquin: Linda Searle, DV (

In the east of the region, good rain of between 40–60 mm has fallen and turned the spring from a poor one into one that is salvageable. Minimal worm testing has occurred over the last month, but I expect to see more tests (WormTest) as producers contemplate the necessity of a first summer drench. Due to the late rain and warm weather, producers should be conducting worm tests, paying particular attention to barber’s pole worm and using the most appropriate drench for the situation.

In the west of the region a few tests have been conducted with varying results.

  1. One producer tested some Dorpers, some of which were scouring, and found 48 eggs per gram (epg) strongyle type and 36 epg nematodirus type eggs present. There were also low levels of coccidia in the submission. These dry sheep had been treated with a long acting moxidection injection in August.
  2. Another producer had some old rams, some of which were noticeably scouring, and deaths were occurring. They were last treated with ivermectin in September 2016. They showed a faecal worm egg count of 36 epg strongyle type and 0 epg nematodirus type eggs. Low levels of coccidia were also found in the sample.
  3. A third producer tested some 6 month old cross bred lambs and found that they had a count of 108 epg strongyle type and 132 epg nematodirus type eggs. There was also low to medium levels of coccidia present in the sample. A larval differentiation was performed and identified that 12% of the sample was black scour worm whilst the other 88% was brown stomach worm.
  4. Another producer with cross bred weaner lambs showed a test of 412 epg strongyle type and 80 epg nematodirus type eggs present, with low levels of coccida also present. A larval differentiation on this sample revealed that the composition was 2% barber’s pole worm, 81% black scour worm, 5% brown stomach worm and 12 % large bowel worm.

The above situations were not investigated by our vets, however, results for the first two cases indicate worms are an unlikely cause of scouring or deaths. Results of the third case indicate drenching is not required, but in the fourth case a drench is recommended to prevent further production loss.

South East LLS

Goulburn: Bill Johnson, DV (

Rainfall has been quite variable over the district in recent weeks, with some localities experiencing an average spring after receiving worthwhile falls. In other areas, annual plants had already set seed before the recent scattered light showers. The prospects for worm trouble in sheep follow a similar pattern to the rain.

Barber's pole worm used to be regarded as making only occasional incursions into our district, and only seen in that one year in a decade or so when we had a wet summer. It is obvious now, after barber's pole has been the main parasite species on some properties for five consecutive years that we need to regard it as part of our regular sheep and goat landscape. Recent laboratory tests suggest barber's pole worms are now present on about 80 percent of farms in our district. You can update your knowledge of this troublesome worm on the WormBoss website. We are also hearing increasing reports that some long-acting products are losing their ability to control barber's pole worms in our area, and this is seen initially as a shorter period of protection against reinfection, and then as an inability to kill resident worms.

Barber's pole will flourish if you have scored much of the recent rain. Sheep on some properties already have worm egg counts about a thousand eggs per gram, the majority of them barber's pole that will hatch quickly with the warmer temperatures and moisture. Areas of the paddock that will stay green into the summer will present the greatest risk.

Breech strike in unweaned lambs is common, with flies attracted to moist green dags, particularly on crossbred lambs. Timely crutching or "bunging" stops the problem, although some producers opt to apply chemicals, while being careful to use one with a suitable Export Slaughter Interval (ESI).

Braidwood: Kate Sawford, DV (

Few WormTest results have been received over the past few weeks, which is perhaps a reflection of declining seasonal conditions. Temperatures are now adequate for all types of worm eggs to develop into larvae, but we don’t yet have adequate moisture. Once again, rain is in the forecast but it remains to be seen if it will fall in the district.

If the rain comes, conditions will be optimal for a buildup of larvae from barber’s pole worm. If you have recent WormTest results, consider repeating the test in 3.5–4 weeks after the wet weather arrives—three and a half weeks is the minimum time it takes for roundworm eggs to develop into infective larvae and then for those larvae to be eaten by sheep grazing pasture, develop into adults in the sheep, and then start laying eggs. If you don’t have a recent WormTest consider doing one now to ensure sheep are not shedding significant numbers of eggs.

I recently saw a case of suspected drench resistance in a recently-purchased buck. The buck was presented to a private veterinarian for ill thrift and scours. It had been repeatedly drenched with four unrelated actives, but there was limited response to the treatment. Despite repeated drenching the buck had a worm egg count (WEC) of 560 eggs per gram (epg) when it was first seen by the private veterinarian. The buck was drenched once again with four unrelated actives. Seven days later the buck still had a WEC of 360 epg.

It is important to remember that few drenches are registered for use in goats. In NSW, in order to use a sheep drench “off label” in goats, a written prescription from a veterinarian is required. Goats break down most veterinary medicines, including drenches, at a faster rate compared to sheep, and therefore in many instances veterinarians will prescribe higher doses of drench to goats compared to sheep.

Drench resistance is particularly common on goat properties and therefore having an integrated parasite control program for goat herds is paramount. The good news is a lot of quality current information is available specific to goats on the WormBoss website. Further, DPI NSW has just published a comprehensive primefact titled ‘Managing worms in goats in NSW’. And don’t forget about your most valuable resource—your local private or district veterinarian. 


Western LLS

Bourke: Charlotte Cavanagh, DV ( and

Broken Hill: Hannah Williams, DV (

There weren’t any WormTests submitted from this region during the past month. Despite some rain in the northern part of the western region over the past week, conditions, in general, are very dry.

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