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New South Wales worms, flies and lice update - October 2016

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides


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


Sheep worm egg counts are on the rise in most areas of New South Wales, which is not surprising given above average seasonal conditions. If it's good for grass, it's good for worms. And good for snails as well, which includes lymnaeid snails, the intermediate host for liver fluke. 

It is critical to do regular worm egg counting (WEC), probably every 4 weeks while worm-risk remains high. Using ineffective drenches exacerbates worm-risk, so it is more important than ever to do DrenchChecks—a WEC on the day of drenching and again 14 days later (in sheep). With organophosphate (OP) drenches—and therefore OP-based combinations—no longer available in Australia (possibly Napfix will make a comeback), drench choices are more limited, which might increase the chance that farmers will inadvertently use ineffective drenches—unless they do regular checks on drenches.

Don't forget that we also have some resistance to flukicides. To test their efficacy, against adults at least, do a fluke worm egg count on the day of treatment and again 3–4 weeks later. There is also the 'copro-antigen test' also called the 'faecal fluke antigen test': ask your adviser. As with roundworms, combinations have also been advocated by experts for treating liver fluke, notably Fairweather and Boray (1999), and more recently Kelley and others (2016). The ones that I can think of, and which we have in Australia as off-the-shelf products, are triclabendazole + oxfendazole and, for cattle only, combination products containing the flukicides nitroxynil and clorsulon. Interestingly, according to Boray, synergism has been claimed for triclabendazole + oxfendazole, but not for triclabendazole + albendazole, even though albendazole on its own has some claim as a flukicide (against adults, when used at a higher dose rate), unlike oxfendazole. The situation is the same with closantel + oxfendazole (once available as 'Closicomb', effective against 6+ week old fluke) vs closantel + albendazole (once available as 'Closal', effective against 8+ week old fluke).

A lot more people will be considering Barbervax, at least in young sheep, including those in central and southern NSW which have been seeing higher numbers of Haemonchus, a situation which is a regular occurrence in the northeast of NSW, 'Haemonchus heaven'.

If it is at all possible, prepare a low-worm risk paddock for young sheep that will be weaned in mid-summer. It's not too late. Check out the WormBoss program for your area.


Do your weaner cattle, weaned in autumn, need a drench? In many areas, numbers of larvae on pasture of that most important cattle roundworm in temperate regions, i.e. Ostertagia, peak in late winter–early spring. These larvae, exposed to cold conditions, tend to become inhibited for 3–6 months, sitting in the abomasum, with development on hold, then resuming development in summer—autumn when the cattle are around 16–18 months of age, possibly producing 'type 2 ostertagosis'. Macrocyclic lactone (ML) drenches are the best for Ostertagia in cattle, including inhibited stages. But remember that resistance of cattle roundworms to drenches is now common. If drenching weaners this spring, an ML-based drench is a good option, even better, use a combination containing an ML and one or more other unrelated broad-spectrum actives. The two options in Australia are Eclipse® (pour-on) and Trifecta® (oral). Consider a DrenchCheck when treating cattle as well, but remember that the egg count post-treatment is done at 14 days.



Central West LLS

Coonamble: Jillian Kelly, DV (

Recent rains and warm temperatures have seen a significant increase in barber’s pole worm burdens. No clinical cases have been seen, but counts of 12,000 eggs per gram (epg) in individual sheep have been seen, and mob averages are commonly in the thousands.

Interestingly, producers who have been proactive in their worm management and who have been worm testing and drenching strategically over the past few years, still have low burdens. Properties with the highest burdens seem to have used unmanaged sporadic worm test/drenching strategies.

A good lesson can be found in this—WormTest, and drench only when necessary.

There are widespread fly burdens and many producers are using chemical prevention and treatment.

A warning
Mosquito and sandfly worry is heavy in the Coonamble area, and they have been reported to cause weight loss in weaner cattle. We are warning producers that Bovine Empheral Fever or Three Day Sickness may arrive in the district in the coming weeks, and are advising producers to vaccinate high value animals.

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

I have seen very few worm test results for the Forbes area of the CWLLS over the last month. Given the recent flooding, access to paddocks will be a problem in the area. As a result of all the water lying around stocking rates will increase on some country as producers struggle to find dry land for their stock. This, along with the ideal conditions for larval survival will mean that internal parasites will be a problem over the next few months. If worms are not currently a problem, monitor with WormTests.

Producers who have a sound integrated pest management program in place are getting low egg counts on worm testing, despite ideal conditions.


Northern Tablelands LLS

Glen Innes: Nigel Brown, DV (

Water supply is abundant this year and we are certainly getting early morning dews, but temperatures are still barely above the required 18°C. Around Glen Innes there have been several cases in both cattle and sheep where larvae seemed to have hatched ‘en masse’ and caused diarrhoea, but with no faecal eggs, since the damage is being caused by larvae. 

Levels of parasitism are probably also exacerbated by low levels of selenium, which can affect growth and condition.  Animals in better condition are better able to tolerate worms and may need fewer drenches, and fewer drenches results in less selection for drench resistance.

Coccidiosis has been seen in a few different mobs of lambs and is probably related to stress caused by the changeable cold wet weather interspersed by a few warm days. Yersiniosis scours with similar causation to coccidiosis have also been seen.


North West LLS

Moree: Justine McNally, DV (

Results from worm testing during September and October are a bit of a mixed bag with black scour and barber's pole dominating the results.

We have unbelievable amounts of feed up here at the moment and pasture stands are still high. Sheep with low to medium level worm egg counts should be moved on to clean pastures to avoid grazing low and picking-up worm larvae. Keep monitoring with WormTest (WEC) and cultures.

Results of worm testing during September and October 2016.



Drench Date

Mean eggs per gram (epg)


Black scour %

Brown scour%

Barber's pole%

Large bowel%

Ewes & lambs




































Ewes & lambs


















Mixed aged ewes & lambs









Mixed aged ewes & lambs




































Mixed aged ewes & lambs









Ewes & lambs



















As pastures are grazed lower, and conditions become warmer and more humid, worm infections could become much more serious.

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

The ewes that returned the 1884 eggs per gram (epg) when tested in October (see the report above from the Moree region) had mean of 632 epg at the end of September, i.e. the worm egg count trebled in 3 weeks. Sheep were drenched in mid-October. It will be interesting to see if there is a change in the proportion of barber’s pole versus black scour in the culture taken after drenching.

Conditions are very favourable for barber's pole worms. 

Murray LLS

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

Deniliquin: Dan Salmon, DV ( and Linda Searle, DV (

This month we saw low worm activity (50–200 epg) in older sheep across the region but high burdens (~1000 epg) were identified in some more susceptible sheep, such as young or sick sheep. The higher burdens were made up of mostly haemonchus in the east of the region and a mixture of strongyle species in the west. These results are consistent with the cool, moist spring we have been experiencing.

Sheep owners should remain vigilant for lice and flies. Lice infested mobs in long wool are starting to show signs of wool damage and control may be required.

Flies have also been reported to be causing major problems in some flocks, including strike on foot abscess and marking wounds. Dermatophilus and fleece rot have also been reported in the west due to an unusually wet spring. Owners should also be aware of an increased risk of M. ovis, which is a mosquito-borne bacteria that causes anaemia.

South East LLS

Goulburn: Bill Johnson, DV (

Abundant high-quality spring pasture is keeping worm egg counts in check, for now. Some mobs of hoggets have needed a drench due to a recent build-up of brown stomach and black scour worms, and monitoring shows barber's pole worms at significant levels in others. It is likely the optimum timing of the first summer drench will be delayed by a couple of weeks this year due to weekly showers keeping pastures green.

Editor's note: Don't delay drenching lambs when they are weaned, if that typically coincided with the first summer drench.

Identifying a paddock for lambs after weaning is a problem following a tight winter, which saw hoggets and lambing ewes rotated over much of the property. Producers are weighing up which paddocks have the best feed and the lowest potential worm contamination, and often not finding a clear winner. Frequent monitoring of worm egg counts after weaning is required to identify any potential breakdown, as the chosen weaning paddock was not low worm-risk.

Blowfly strike of untreated wounds following marking and mulesing, and sheep with dags is widespread, and will get rapidly worse as daytime temperatures rise. There have also been numerous cases of photosensitization across the district, affecting just a few sheep in many mobs. Affected sheep rub their swollen ears and eyelids on trees and fence posts, often to the point of making them bleed, and flies are quick to attack these fresh wounds.


Central Tablelands LLS

Mudgee/Merriwa: Nigel Gillan, DV (

WormTest results from the Mudgee district in the past month have been mixed, ranging from very high egg counts (100% Barber's Pole) to very low counts. In one case, diarrhoea and weight loss were reported in a mob with a negative worm egg count—this is a reminder that not all cases of scouring are due to worms. Current warm, wet conditions will favour the development of barber's pole larvae on pasture, so monitoring of egg counts is wise. No reports of mortality due to barber's pole have been received to date.

For October 2016 state outlooks, please follow the links below:
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