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

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides

Armidale: Rad Nielsen, Veterinary Health Research (

The terrific winter and early spring rainfall has ensured a good spring season, and if further rain falls, worm activity will be high over the coming months. Already the VHR Laboratory has seen mean worm egg counts trend higher over the past few weeks. Sheep producers will need to be mindful of worm activity and utilise grazing strategies to maintain some control over paddock contamination.

Given the advanced state of drench resistance across the New England/North-West region and the current unavailability of naphthalophos (Rametin®), high efficacy anthelmintic products are extremely limited on a large proportion of properties. The few drench options that are available need to be used judiciously and as part of a multi-active product in order to maximise their longevity. Drenching should be conducted only after worm egg count confirmation rather than given on an ad-hoc basis. Strong consideration should also be given to implementing the Barbervax® vaccination program this worm season. This product is now registered for all ages of sheep and has proven ability to significantly enhance Haemonchus (barber’s pole worm) control.



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

Now is the time to start preparing low worm-risk weaning paddocks.

In many areas ewes lambed in September, with weaning (of Merinos) recommended to occur 12–14 weeks after the start of lambing. Provision of a low worm-risk paddock for weaners could make a big difference in controlling barber's pole worm, in particular.

For the tablelands areas in NSW, spelling paddocks in the 3 months prior to weaning will prevent contamination with worm eggs. Grazing pastures with cattle during this period can help prevent them from becoming rank.

In warmer areas during spring and summer, larvae on pasture die faster than in the cooler months, so preparation of the summer weaning paddock takes about half the time required for preparation of a spring lambing paddock. In much warmer areas, such as Nyngan or St George, the time required to prepare summer paddocks is only 2 months.

Another option is so-called 'smart grazing - summer'. This involves grazing paddocks with just drenched sheep up to 21 days after the end of the protection period of the drench, known to be very effective by testing on your property. Obviously, in the case of short-acting drenches, sheep can be grazed on the paddock being prepared for up to 3 weeks from the time of drenching, as none or only a very few worm eggs could be shed in faeces during this time.

More information:

Bourke: Charlotte Cavanagh, VO (

Internal parasites are certainly on the differential disease list for veterinarians this month, if not as the primary cause of death, then as a contributing factor.

In the last few weeks, worm tests have been submitted from three properties, with one property testing each of four flocks. The worm egg counts (WECs) ranged from 0 eggs per gram (epg) to 760 epg, with the higher counts associated with higher rainfall properties.

In the south of the region, a property running dairy goats is, once again, battling internal parasites responding to the worm-perfect conditions of warmth, moisture, lush feed and lack of rested paddocks for stock rotations. The most recent WEC was 928 epg in a mob of mixed sex, mixed aged goats, reported to be in good condition, but with varying degrees of scour.

There have also been some stock losses in the district, and these cases are still under investigation.

The recommendation is to WormTest on a monthly basis throughout this high worm-risk period and following drenching conduct a post drench check, DrenchCheck.  



Central West LLS

Coonamble: Jillian Kelly, DV (

The Central West area is experiencing widespread flooding and many landholders have not seen or handled their stock in weeks. The combination of warmer weather going into October, immunocompromised and flood affected stock, and wet, wet, wet ground will result in a perfect barber’s pole worm season. Producers should be worm testing from late September onwards to monitor for any rapid build-up in worm numbers. This might be the summer to use a long acting drench, depending on WormTest results and any resistance in worms to drenches (remember, not all drenches work on all farms!) If in doubt, do a DrenchCheckworm test 14 days post drenching to ensure the drench has cleaned all the worms out of stock.

The Coonamble area is already experiencing significant fly issues and this will continue throughout spring and into summer. Cattle lice are still active in the Coonamble area, however the hotter weather should clear this problem without requiring treatment. The other worry at the moment is the presence of mosquito burdens that spread diseases such as three day sickness and cause incredible irritation to livestock, pets and humans.

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

A few cases of scour worm affecting young sheep have been identified in the Forbes area in the last few weeks, and a warning that a 'wormy' spring is imminent due to abundant moisture and increasing temperatures. Producers need to wean onto prepared 'low' risk paddocks and do regular WormTests to monitor for any rapidly rising worm burdens.

Flies will also be a major problem with the temperatures warming, lush pasture growth, and scouring sheep with increased amounts of dags. Producers should adopt an integrated pest management program to minimise the build-up of fly numbers and protect their sheep.


Riverina LLS

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

Producers are reminded that spring is well underway, albeit with an overabundance of rainfall! The region has now registered 22 inches (558.8mm or 1584 points) of rain from May to early September, with September already the wettest on record, and about 10 days still to go! Temperatures have fluctuated from an average low of 6°C to an average high of 14°C. 

Worm egg count tests have been conducted throughout the area, and averages of 50–500 eggs per gram (epg) have been recorded. Larval differentiation results have identified mainly Trichostrongylus (black scour worm) species, although barber’s pole worm has been present in some tests, and also identified during field visits.

As the weather continues to warm up, worm burdens on properties throughout the region will be on the rise, and as such producers should be on guard.

Producers are reminded to conduct worm egg counts (WormTests) on mobs, especially susceptible mobs such as weaners, every 4–6 weeks.

Spring is an ideal time to perform a drench resistance test on your farm. Follow the guidelines outlined on the WormBoss website or contact your local district veterinarian who can assist with this endeavour. 

Flies have begun to appear on various farms and as such, crutching and the application of fly strike preventatives, has begun. 


North West LLS

Moree: Justine McNally, DV (

Conditions around Moree are very good. There is an abundance of herbage and it is very lush. Feed is long and sheep are no longer grazing close to the ground. Now that temperatures are warming, worms are likely to become more active.

Summary of worm egg counts (eggs per gram (epg)) and larval differentiations (percentage (%)) from the Moree area for September 2016.



Mean (epg)

Range (epg)

Black scour (%)

Brown stomach (%)

Barber's pole (%)


5yr ewes







7yr ewes







8yr ewes







6yr ewes







1yr ewes







1-6yrs ewes







weaner ewes







mixed age ewes







1-4yrs mixed







5yr ewes







5-6yr ewes







mixed age ewes







10mth wethers






Wee Waa

2yr ewes






Wee Waa

4yr ewes






Wee Waa

8mth lambs







South East LLS

Goulburn: Bill Johnson, DV (

By this time of year, we expect enough high quality feed to be available to help young sheep overwhelm any winter worms, and dilute larval pick-up. But pasture growth is slow on waterlogged soils, and beneath overcast skies. As a result, high levels of black scour and brown stomach worms have developed in some mobs of merino hoggets. In all cases, these young sheep have continued to graze the same country throughout winter. Some of them have been set-stocked, while others have grazed in a four- or six-paddock rotation, with only a short reprieve of a couple of weeks following each drench before starting to scour and rapidly lose weight again.

Worm egg counts give a measure of pasture contamination, that is providing the previous drench was effective; counts approaching two thousand eggs per gram and predominantly scour worms, are common in these scouring hoggets, indicating that the previous drench was ineffective or that the pasture is heavily contaminated. Producers should budget on hoggets needing a follow-up drench in another four to five weeks, if they need to again return to the same paddock.

The majority of worm egg counts now have some Haemonchus (barber's pole worms). We've become accustomed to seeing low proportions of Haemonchus in relatively low worm egg counts at this time of year. But in some mobs, we now have more than 80% Haemonchus in pretty solid counts. Coupled with what will start out as a bumper spring, there is the prospect that barber's pole populations in some sheep could cause deaths by New Year.

It is important to know the situation in your sheep now, with a WormTests and larval culture.

And with all that surface water about, the small freshwater liver fluke snail will have a breeding bonanza in a few weeks. These snails multiply the free-living stage of liver fluke, able to turn a single fluke larva (miracidia) into four thousand or so fluke cysts waiting on vegetation for a passing grazing animal.

The trick is to remove liver fluke from infected sheep, cattle and goats now, prior to them infecting the freshwater snails. Recent tests have shown a high percentage of properties with liver fluke in cattle, so you'd expect the same to apply to sheep flocks run on properties with flowing creeks or seeping springs.

Coughing lambs this month were found to have lungworm. Rain helps larvae of this parasite escape from faeces, and short winter pastures mean larvae don't have far to climb. Milder winter temperatures with few heavy frosts also encourage survival of lungworm larvae. Most drenches kill lungworm.

The run of wet weather continues to play havoc with lice control programs. While some products remain effective with rain, and need not be applied immediately off-the-board, some properties have taken a month to shear a week's worth of sheep. It will be important to closely monitor treated sheep with five to six months' wool to detect signs of possible treatment failure.

It's a big year for sheep dags, too. Green feed and delay in getting crutchers will result in a lot of sheep susceptible to breech strike in a few weeks. And so many rainy days during lambing lead to an unusually high proportion of merino lambs having extensive dermo at lamb marking. Some of these lambs are so severely affected they have difficulty walking. We rarely have to worry about flystrike in unweaned lambs, but these lambs with dermo will be targets for body strike in spring.

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