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

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






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

I said this last month, but heading into early winter is a reminder to treat for liver fluke. This is the most important of the strategic treatments for liver fluke, and the ideal is to use a highly effective flukicide, which gets 'all stages' of fluke in the liver. Alas, these days you also have to consider the possibility of fluke being resistant to one or more flukicides.

To check if the flukicide worked, you need to do a test on the day of treatment, and again 21 days later. This is the simplest approach, but consider talking to an adviser who knows about fluke. The tests?  A liver fluke worm egg count, or the faecal fluke antigen ELISA (coproantigen ELISA).

The onset of cooler weather doesn't of course mean the end of worms till spring.  While many of the worm lifecycles slow right down with colder conditions, the infective larvae produced when it was wetter and warmer (e.g. March, in many areas) will make it through to spring, albeit in slowly declining numbers.

Looking at sheep WormTest results for March, there was a spattering of tests with high egg counts, which means a correspondingly high level of pasture contamination going into winter.

Keep up a program of regular Worm Testing.



Central West LLS

Coonabarabran: Alix Ferguson, DV (

Mean egg counts have ranged from 0 eggs per gram (epg) to 4,120 epg this month in the Coonabarabran area.  This table gives an example of the variation in larval culture results this month. Performing a worm egg count with the addition of culture will give valuable information for suitable drench selection, and management decisions. 


Mean (epg) Range (epg) black scour worm % brown stomach worm % barber's pole worm %
384 0-840 49 15 36
60 0-160 34 53 11
1216 0-4120      
100 0-240     100
380 0-1040     100
60 0-160      
20 0-60      
208 0-840      
44 0-200   94 6
56 0-440 1 2 92
48 0-120 18 3 74
412 1400      
0 (all others) 
952 40-3920 3 3 94
240 40-440      
4 0-40      
100 40-400      


Coonamble: Jillian Kelly, DV (

For all producers, Worm tests with larval counts are recommended now to ensure you know where your mobs stand.  

Recent worm tests around the Gulargambone area have seen a high percentage of black scour worms, which is worrying heading into the cooler weather.  If these burdens are not treated with an effective drench now, or monitored into winter, they may cause losses. 

On another property near Carinda, a post-drenching worm count has revealed moxidectin resistance. Producers were advised to consider doing a Worm Egg Count Reduction Test (DrenchTest) in suitable mobs of weaners in spring.  

Overall, the number of wormtests going to the State Veterinary Diagnostic Laboratory (SDVL) at EMAI is very low, so my knowledge of what is happening worm-wise in my area is limited.  Is this because producers are not wormtesting? Or because producers are using private laboratories?


Nyngan: Erica Kennedy, DV (

There have been very few worm tests submitted in the Nyngan/Warren areas to EMAI over the last couple of months, so I have not seen too many results since then. The local veterinary clinic has done a few counts and have not seen major burdens, and local agricultural supply stores have done quite a few in-house counts and have seen varying results—some with 0 egg counts others with >800 eggs per gram (epg) average counts. Of the few results I have seen the average counts were usually <500 epg, but the larval cultures are really catching my eye at the moment.

As I expected with the transition seasons (autumn and spring) there is a real mix of predominant worm types between properties and indeed within properties. Brown stomach worm (Ostertagia now called Teladorsagia) has been slightly more dominant in the few larval cultures I have seen but on all properties that performed larval cultures, there has been a mix of brown stomach, barber’s pole and black scour worms. This is vitally important information when deciding whether to drench and if so, what with!

I strongly recommend to all producers to perform a larval differentiation in autumn and spring (if doing cultures all the time isn’t an option) to see what is on your property during those times of the year where you could see any type of worm predominate. If you must drench, it is imperative that you drench check by performing a worm egg count and larval differentiation at 14 days (if using a short acting drench) after drenching, if using a mid to longer acting drench then times will vary. [Ed: For mid to longer acting drenches, also WormTest at 30, 60 and 90 days after treatment depending on the length of persistent activity of the drench. If the drench is shown to be ineffective at one of the earlier tests, then the later test/s will be of no value].

Knowing what to do and when to do it can be a bit confusing (especially when being told different things by different people), but if there is ONE thing that would most improve a producers worm control I think it would be doing regular worm worm egg counts! In our area, this means every 4–6 weeks in favourable conditions and every 6­­–8 weeks when things are not so good (sustained dry or cold), in addition to this, do a worm count several weeks after good rain that produces a green pick. 


Northern Tablelands LLS

Inverell: Andrew Biddle, DV (

It has been a nice mild autumn so far. A couple of weeks without rain has really got pasture moving and sees most graziers in the west of the Northern Tablelands heading into winter with plenty of standing feed and for many, oats as well.

Worm numbers seem steady but there is no sign of barber’s pole signing off any time soon. Producers are advised to continue Worm Testing to determine if any further barber’s pole drenches will be required.

Glen Innes: Nigel Brown, DV (

Plenty of worms around this season, but one interesting case was a Faecal Egg Count Reduction Test (FECRT) or Drench Test, done on a flock with an average worm egg count of 1272 eggs per gram (epg) and 99% Haemonchus. After treatment, almost 50% of the 60 animals in the test (10 sheep in each of 6 treatment groups) had zero egg counts. Many had counts ranging from 40 epg to 320 epg but in the Albendazole treatment group one count was 4760 epg, and in the Cydectin group one was 2520 epg. The lowest results were in control group!!! 

[Ed: pre-drench worm egg counts would have helped to determine if the 2 sheep with the high post drench worm egg counts were mis-drenched].


North West LLS

Moree: Justine McNally, DV (

Not as many producers participated in worm testing this month but there was a predominance of brown stomach worm (Ostertagia now Teladorsagia) in the counts that were cultured.  As there were so few tests done, you probably can't hold your hat to it, but both places with high percentage of Teladorsagia in the culture are in the west.  The ones with the high percentages of barber’s pole are in the east.  From this you could maybe say that producers in the western areas should be mindful of brown stomach worm and those in the eastern regions, barber’s pole.

Conditions have certainly dried off here so pastures are starting to be chewed down, and with the odd shower about, green pick is seen here and there.  This will set places up for worm burdens if producers are not careful and WormTest

Class Drench Drench
scour %


pole %
Lambs Pyrimide 3+ 23/11/16 196 0–960      
Lambs Pyrimide 3+ 23/11/16 32 0–120      
Lambs Rametin+ Startect 17/02/17 60 0–280 5 0 95
Lambs Q Drench 12/12/16 0 0      
Ewes     0 0      
Mixed age ewes Q Drench 1/01/17 220 0–480 0 0 100
2 yr ewes Cydectin LA 1/03/17 4 0–40      
Weaners Eweguard 15/01/17 24 0–120      
Ewes and weaners Zolvix 2/03/17 28 0–80      
Mixed ewes     144 0–360 26 67 5
Mixed weaners Weanerguard 10/12/16 0 0      
2 tooth wethers     40 0–80 1 91 3
XB lambs Nilverm 15/12/16 96 0–240      
XB lambs Nilverm 4/11/16 36 0–160      


Murray LLS

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

Deniliquin: Linda Searle, DV (

There have only been two worm tests this month, one from the west and one from the east of the region.

In the west, the results were from a mob of 10–11 month old ram lambs that were in poor condition, but not noticeably scouring. They had been drenched in September 2016 with a white drench (Albendazole) and there had been no rain for the 3 months prior to the test. The results showed an average egg count of 1276 eggs per gram (epg) strongyle type and 36 epg Nematodirus. The strongyle type eggs were differentiated into 85% black scour worm, 14% brown stomach worm and 1% large intestinal worm (large bowel worm).

In the east, results came from a mob of 2 and 3 year old ewes that were in good condition and about to start lambing. They had most recently been drenched in December 2016 with a triple combination drench containing abamectin, oxfendazole and levamisole. The average worm count was only 48 epg strongyle type and 4 epg Nematodirus with most of the individuals in the mob having a zero epg count, and the highest individual count was 360 epg strongyle type and 40 epg Nematodirus. Very low levels of coccidia were also found in two individual sheep.


South East LLS

Goulburn: Bill Johnson, DV (

Worm activity has been pretty quiet on most properties, despite areas to the east looking like late spring, and areas to the west green, but needing rain. Most worm egg counts have been low, but some producers have decided to drench where those counts will result in significant contamination of paddocks likely to be used for lambing in a couple of months. This drench decision has also been based on worm type present. There has been an increase of winter scour worms (brown stomach and black scour worms) and a reduction in the proportion of barber's pole worms, reflecting the greater effect of the hot, dry summer on barber's pole eggs and larvae.

Thin-necked intestinal worms (Nematodirus) continue to prove they are under-rated. The owner of a large mob of merino weaners noticed "they weren't doing as well as they should". Very few were scouring, but they hadn't improved in condition with the arrival of green feed, and a few of them were weak when mustered. This bloke does his own worm egg counts, and immediately collected dung samples, being sure to include some taken directly from these weak sheep. To his surprise, the worm egg counts were very low, including only a trace of Nematodirus eggs. He elected for an autopsy which found excessive levels of immature (i.e. not yet egg-laying) Nematodirus. This worm frequently causes ill thrift and losses in weaners a couple of weeks after the autumn break, and before worm egg counts rise significantly.

Most mobs have at least a couple of scouring sheep at present, but some mobs have a high proportion. In most cases, this scouring has more to do with feed, like the prolific crumbweed, than with worms, so that drenching has no impact. These daggy sheep are prime targets for flystrike.

For the first time in several years, producers are seeing significant body strike in weaners and to a lesser extent in adult sheep. Some of this is related to a carry-over from extensive fleece-rot caused by the wet spring, rejuvenated now by autumn rain. It has provided an opportunity to identify and cull these highly susceptible sheep. Blowfly activity has begun to diminish with a few light frosts.

And speaking of frosts, now is a good time to give a drench for liver fluke to mobs that have grazed fluke-prone paddocks over summer. Dung samples tested for liver fluke show that this parasite is regaining territory it lost during many years of drought. The liver fluke life-cycle relies on a small fresh-water snail, which needs slow-flowing water in creeks or spring-fed swamps. Properties which traditionally had a "fluke problem", but haven't needed to drench for fluke for several years are now recording fluke again. The best fluke drench to use at this time of year will remove as many of the immature fluke as possible, as well as any adults present.

Getting rid of lice should be easy, shouldn't it? You just need a clean muster and an effective chemical. But it is surprising how difficult it becomes when you factor in everything else you need to do on your farm, like timing of shearing, joining and lambing. One producer had lice in ewes for a second time after making a concerted eradication effort using an off-shears product with no known resistance. He joins ewes off-shears in autumn, but knows that shearing rams immediately prior to joining affects fertility. The rams are shorn and treated for lice immediately after joining, and were lice-free prior to joining. Despite this, the rams were likely responsible for the breakdown in the eradication program. Lice move to them from lousy but treated ewes, and later return to the ewes from the rams when any chemical protection period has expired, during the mating period. Lice eradication is unlikely here until changes are made to the timing of these management operations.


Western LLS

Bourke: Charlotte Cavanagh, DV ( and

Broken Hill: Sophie Hemley, DV (

Worm egg counts (WECs) from the Far West have been extremely variable during the early autumn period.

  • A WEC from a herd of Angus heifers in the Hillston district returned a count of zero eggs per gram (epg).
  • A pooled WEC of 3040 epg (strongyle type eggs) was recorded from the “tail” lambs of a self-replacing Merino flock in the Broken Hill region. Larval differentiation elucidated the burden as 82% black scour worms (Trichostrongylus spp.). Interestingly some of these poor-doing lambs also had a significant lung worm (Dictyocaulus filaria) burden on post mortem. Pooled WECs from clinically unaffected ewes and lambs from the same property averaged 600 epg. 
  • Another self-replacing sheep flock from the Broken Hill region returned an average WEC of 4948 epg (strongyle type), with individual counts as high as 11,400 epg and 30,200 epg. The highest counts were from weaner lambs in good body condition score with no signs of scouring. These sheep were treated with a pour-on macrocyclic lactone off-shears, for the control of body lice (Bovicola ovis) and the treatment and control of abamectin-sensitive internal parasites. A DrenchCheck, 14 days later, yielded zero epg—suggesting there was no drench resistance in these sheep.

Variable WECs from the Western region serve as a timely reminder for all producers to complete a WEC on their livestock as the weather cools down and feed availability is reduced. 

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