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New South Wales worm update - July 2013

Rad Nielsen, Veterinary Health Research, Armidale (

Recent faecal egg count results from the New England region are variable.

Some high worm egg count results (2-3,000 mean epg) have been seen, along with a number of situations where the worms have been kept well in control for a sustained period.

A grazier near Armidale reported in late June an instance of clinical haemonchosis in lambs despite quite a modest mean worm egg count, inferring that there had been a recent high larval intake under his slow rotational grazing system (paddock in question had been rested for 2 months prior). This example highlights the ability of worm larvae to persist on pasture and subsequently render paddocks “high risk” for many months, regardless of the time of year.

Worm monitoring prior to administering pre-lambing drenches is advised so as to confirm the need for treatment and fine-tune drench selection. In many cases it may not be necessary to use broad spectrum treatments, in particular sustained activity preparations. Lambing paddock preparation is the most effective and sustainable solution for ensuring good worm control over the lambing period.

Stephen Love , Veterinarian, State Coordinator-Internal Parasites, NSW Department of Primary Industries, Armidale (
We are coming up to Spring lambing in many parts of NSW.   Of course it is too late to preach to you about the critical importance of lambing paddock preparation.   There is good information on this in WormBoss of course. Type 'lambing' into the search box, and also read the 'Your Program' for you region.   It is not onerous: it is brief and to the point (which I think may be a tautology, although I suppose you can brief but pointless).

WormBoss including 'Your Program' is great! (Have I mentioned that before?)

Depending on your region a pre-lambing drench may or may not be recommended as routine. Certainly you need to have a good program of WormTesting to see what worm burdens ewes are carrying before lambing, and what ewes and lambs are carrying  between lambing and weaning.  Again, WormBoss has the answers (including the Drench Decision Guides).

If/when doing a pre-lambing drench, consider a DrenchCheck also. If the drench wasn’t fully effective, you will 'reap the whirlwind', i.e. big worm problems for months downstream from lambing, in ewes and lambs, especially if you did not prepare low risk lambing paddocks.

We are also approaching August, an 'A' month.  'A' months are the two most important months to drench for liver fluke (sheep, cattle, goats, alpacas), with April being the most important.  Some need to drench for fluke in April only (i.e. April-May, when the frosts start), some need to do an August drench as well, and some with very 'flukey' farms need one in February also.   Consider rotating between unrelated flukicides (or using combination flukicides!) on each occasion. Resistance is out there.

If you don't know if you need to treat for liver fluke, test for liver fluke in April, August and February. Testing options include the liver fluke worm egg count, the liver fluke antibody ELISA (blood test), and the faecal fluke antigen test. All have their pros and cons.   More information:  Search for 'liver fluke' at, check out the DPI website ( ; ) and go to the CSU Vet Lab (Wagga) page for information on the fluke faecal antigen test (   You may need to contact the lab for more information).  

Remember that liver fluke infective larvae (metacercariae), unlike round worm larvae, occur in patches on a farm (where the intermediate host (snail) habitat is), so some mobs on a flukey farm could be negative on testing, depending on grazing and treatment histories.

Liver fluke is a zoonosis. There is more information here :  as well as in the NSW DPI Primefacts/FactSheets on liver fluke.


Lachlan LHPA

Belinda Edmonstone and Nik Cronin, Forbes (  (

In the central area of the Lachlan LHPA there were 12 worm test performed for the month of June with average faecal egg counts ranging from 0-3508. Individual counts range from 0 – 11000.

The much welcomed rain has seen an increase incidence in worm related issues. Losses occurring in ewes with lambs at foot were due to a pure moxidectin resistant Barbers Pole worm infestation. With increased drench resistance occurring producers really need to know which drenches are performing on their property, so DrenchCheck or do some Drench Resistance Testing.

Kasia Hunter, Condobolin (

In the western area of the Lachlan LHPA two WormTests were conducted during the past month on two separate properties. The average faecal egg count on each of these two properties was 80 and 100 eggs per gram (epg), respectively, with an individual range of 0 – 160 epg. Larval cultures were not performed. No parasite related health issues have been reported or observed. However producers should remain vigilant particularly with respect to more susceptible stock classes such as pregnant ewes and lambs. Ensuring autumn lambs are weaned onto clean pastures is a crucial step in minimising production losses. Individual situations can vary significantly between properties, therefore if you are unsure of the parasite status of your sheep - WormTest.

Central West LHPA

Evelyn Walker, LHPA DV, Dubbo (

Average strongyle egg counts were 376 in Dubbo with 99% Barber’s pole worm. Wellington and surrounding areas had an overall average strongyle egg count of 287 with mixtures of mostly Barber’s pole worm and some Black scour worms present. Although these worm egg counts are fairly low for this month, please be aware that worm activity is best measured on an individual farm basis. What your neighbour has could be different to what you have. And yes, Barber’s pole is still hanging around and could affect you. Earlier this month, I saw heavily pregnant ewes dying of pregnancy toxaemia and Barber’s pole worm infection. A double whammy unfortunately. In this case, the ewes had not been drenched since early summer. It’s therefore important to check your pregnant ewe mobs with a Wormtest to see whether they need a drench prior to lambing.

Tablelands LHPA

Jim McDonald, Yass (

The Yass District has received good rains this month which has improved the paddock pick at little, but not enough to give weaner sheep and pregnant ewes enough feed to get them through winter in optimal condition on most holdings.  This sub-optimal nutrition has lead to the maintenance of worm populations with counts varying greatly from 3000 epg with 95% Barbers Pole down to less than 100 epg with a mix of types.

Until the end of winter sheep will need careful monitoring to avoid a parasite ‘crash’, especially if feed is tight.  Monitoring both Worm egg counts and paddock feed is essential heading into lambing.

There have also been several clinical cases of fluke appearing in both sheep and cattle so include liver fluke in any monitoring and decision making during this time.

Riverina LHPA

Gabe Morrice, Narrandera: (;

No WormTests have been conducted over the past month in this area.

Dying lambing merino ewes that had not been drenched for over twelve months were found to have FECs of 3720 epg.

Dan Salmon, Deniliquin (

Not many WormTests but what there were had low counts.

One in particular was from 12 month old ewes drenched in December that had zero epg.

Colin Peake, Hay; ( );

Only 1 WormTest in the last month from one of the local schools. 30 Dorpers on small paddocks, has lost 1 and others losing weight.

Individual counts for strongyles ranging from 80 to 4720 with an average epg of 1648 and nematodirus ranging from 0 to 120 with an average of epg 28.

The differential was 92% haemonchus and 8% trichs. No liver fluke, tapeworm & coccidian.

Drenched with Cydectin SE and a 12 day post drench Wormtest with an average strongyle epg 1636 (range 0 – 13,200) and nematodirus 0.

We have our first reported case of moxidectin resistance in the western Riverina.

This shows the importance of post drench WormTesting to see how effective the drench is that has been used.

It can save a lot of money, time & help minimise pasture contamination by acting quickly when you recognise that you have drench resistance on your property.

New England LHPA

Andrew Biddle, District Veterinarian, Glen Innes (

Generally sheep in an around Glen Innes and Inverell are faring well this winter. All be it a few mobs of weaners with carry over worm burdens from the Autumn or liver fluke have succumbed to multifactorial ill thrift. These have manifested clinically as bacterial enteritis, Coccidiosis or mycoplasma ovis. In one case those affected by the ill thrift made up almost 20% of the mob and the final mortality was close to 10%.

In each case I believe the problem started due to the onset of drench resistance in a previously effective active and inadequate monitoring.

Tablelands LHPA

Bill Johnson, Goulburn, (

Monitoring of ewes either prior to lambing or prior to lamb marking predominates. Some producers have reluctantly discontinued using long-acting pre-lamb drenches for the first time in several years, citing economics.

They are nervous about the prospects of controlling worms in ewes at lambing without capsules or long-acting drenches. Most of them are faring pretty well, providing the lambing paddock chosen had not been grazed by young sheep since February, and feed available is adequate. Few of the mobs monitored would need drenching at lamb marking.

Significant worm egg counts, averaging a couple of thousand, have been found in some recent tests, with the ewes in good condition and doing a good job on their lambs. Surprisingly high proportions of barber’s pole worms have been found as the cause of these high counts. The mobs often have a history of one or more recent drenches with an ML (“mectin”) drench, most often abamectin.

Bruce Watt and Jeff Eppleston at the Bathurst end of our patch have confirmed resistance to abamectin in barber’s pole worms on several farms, and we now have evidence this is happening here as well. If barber’s pole worms are present in your sheep, avoid using drenches that only contain abamectin.

Where lambing paddock selection hasn’t kept to the script, a small number of mobs of lambing ewes have suffered the often fatal combination of malnutrition and worms, predominantly brown stomach worms. Dramatic weight loss in these ewes gives the first clue, but this is often masked by wool.

Low levels of liver fluke continue to show up in mobs that have grazed creek and swamp paddocks. A fluke drench ‘coming out of the winter’ is an important part of controlling liver fluke in sheep and cattle on high-risk paddocks.

Greg Curran, Broken Hill, (

While Charlotte Cavanagh is on leave, I've been checking her WormTest  results.
The main feature is the drop-off of worm egg counts in people in the Far Northwest. One large Brewarrina flock/stud that had major worm problems during the wet years, mainly Haemonchus, has been doing thorough surveillance. The latest round showed very low counts across the flock, but with low counts in a mob of stud ewes.

WormTesting in the remainder of the area has dropped to much lower levels than seen in the wet years, but all are similar to the Brewarrina results.

We've had very good cool season rains, perhaps the best in a decade, so we may see more cool season worms either later this year, or in autumn-winter next year. No testing in the "central" Far West. A lot of dry feed (grass and chenopods) still, with good herbage between, and relatively low stocking rates, so the worm risk is relatively low.

The greater number of Dorpers and newer breeds that browse higher up may have reduced general risk, although we've seen worms in Dorpers/Damaras.


Tony Morton, Wagga Wagga (; Amy Shergold, Wagga Wagga. (

July is the peak time for larval availability of the two most important sheep worms in the Hume district i.e. the small brown stomach worm and black scour worm. Exacerbating this it is commonly a time of:

  1. Short pasture so a higher than usual proportion of the available larvae may be consumed and
  2. Lactation that decreases ewe resistance.

Monitoring in late July or August is therefore important to assess if there is an excessive worm burden in your sheep. Bear  in mind it takes about two  weeks for the larvae that  have been  eaten  to  start producing eggs, this can  sometimes mean  that  there is low count in July  when  most  of the worms are present as larvae in the sheep yet  there is a high  count  a month  later when  they  are egg laying  adults.

North West LHPA

Fiona Fishpool, LHPA, Moree (

There have been minimal WormTests completed in the last month in the North West district. Those that were conducted showed insignificant faecal egg counts except for one case of Haemonchus in the Warialda district. Worms are still likely to be about for those who haven’t drenched, particularly in the southern slopes, but counts will likely remain low until overnight temperatures start to rise. It is important to note that the moist conditions throughout the region and unusually warm night temperatures for this time of year (more than a handful above 10 degrees) are sufficient for Haemonchus larvae to hatch and develop. As such, the Haemonchus spring rise could come early this year.

For July 2013 state outlooks, please follow the links below:
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