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New South Wales worm upate - September 2013

Rad Nielsen, Veterinary Health Research, Armidale (

Worm monitoring results at VHR over the last month have been varied. Some extreme counts have been seen in ewes post lambing (in excess of 3,000 epg mean with clinical haemonchosis), whilst other producers appear to have good control of worms. The difference largely comes down to management and paddock planning. Paddocks that were “wormy” back in Autumn are still very likely to be a high larval challenge environment (even more so this year after a mild winter), whilst ewes lambing in prepared “low worm” paddocks have low-moderate infections at lamb marking.

Early Spring has been dry across most of the New England, however the mid-September rainfall event will have triggered worm development. Graziers will need to be particularly vigilant from now onwards so as to avoid any nasty surprises. Regular worm egg counts (every 3-4 weeks) are the best way to monitor the worm status of sheep.


Lachlan LHPA

Belinda Edmonstone and Nik Cronin, Forbes (  (

In the central area of the Lachlan LHPA there were 10 WormTests performed for the month of August with average faecal egg counts ranging from 0-960. Individual counts range from 0 – 1060. According to this worm counts have dropped over the last month however producers need to still be vigilant regarding monitoring of worms particularly with the recent widespread rain. A good spring will ensure worms eggs and larvae will survive on pasture becoming a source of infection for grazing animals.

Kasia Hunter, Condobolin (

In the western area of the Lachlan LHPA no WormTest results were received in the past month. No parasite related health issues have been reported or observed. Many producers are in the process of weaning lambs, therefore the selection of an appropriate weaning drench should be given due consideration. Weaning lambs onto low-worm risk paddocks is also equally important. If you are unsure whether your chosen drench has worked, it is recommend to conduct a ‘DrenchCheck-Day10’ – this involves the use of two WormTests, one before treatment and one 10-14 days post-treatment to see how effectively the selected drench reduced the worm egg count. Drench resistance is common, so don’t get caught out!

Elizabeth Braddon, Young (

The eastern end of the Lachlan LHPA has had reasonably warm weather in the past few weeks with maximum temperatures easily rising above 10ËšC and with about 30 mm of rain so producers should start to be on the lookout for worm activity.  Testing recently shows that while overall counts remain low for the moment – weaners were averaging 111 epg and pregnant / lactating ewes averaged 280 epg, the potential for worm activity to increase quickly as daytime temperatures increase is there.  Of the 4 larval cultures performed all four had >75% Haemonchus (Barber’s Pole worm) population (range 75%-96%).  This early showing from Haemonchus means that producers will need to be on the lookout for clinical disease in the immediate spring period rather than later in the season like we have seen in the past few years.  Now would be the time to do some wormtests on your own farm combined with a larval culture to determine which worm species are there so that choosing an effective drench is made all the easier. 

This time of year is also the time to consider changing your drench class to start a new annual rotation – normally timed with the first summer drench.  This doesn’t mean just changing product names (eg. cydectin to avomec) – it means changing actual active ingredients in the drench.  In the example of cydectin to avomec, the class of drench is still a mectin!  Annual rotation of drenches means changing from a mectin based drench to a BZ (Benzimidazole or white drench)/ Lev (Levamisole or clear drench) etc.  The other thing to consider is that now we know the level of drench resistance generally in the population, we are recommending that you try to stick to a combination drench – one that has multiple actives – rather than just a single drench.  By this I mean using a combination of Mectin + BZ + Lev or OP (Organophosphate)+ Mectin+ BZ just to name a few.  There are many different products that fit into these categories so if you need assistance on choosing a drench class on your farm, give your local DV a call. 

Central West LHPA

Evelyn Walker, LHPA DV, Dubbo (

Sheep worm egg counts have varied from property to property in the Dubbo and surrounding areas. Few wormtest reports have been received. Of those testing this month, worm burdens range from low to medium, with mixed infections of Barber’s pole, Black Scour and Brown stomach worms. Only one property which was investigated had deaths due to heavy black scour worm burdens. I am also seeing heavy worm burdens in imported sheep to the area. Let that be a reminder that quarantine drenching is important followed by a WormTest 10 to 14 days later to make sure the drench worked is equally important.

Tablelands LHPA

Bill Johnson, Goulburn, (

Worm issues in this patch of the Tablelands are proving to be as variable as our spring weather. Ewes lambing on declining pastures have lost weight and died with heavy worm burdens of predominantly small brown stomach worms, with little evidence of scouring. Unweaned Dorper lambs a few months old lost weight, scoured and died also with the same worm. Mixed age Dorper sheep and a mob of Merino ewes had all the symptoms of Barber’s pole worms (weakness, anaemia and bottle jaw, leading to death), with masses of these worms found at autopsy. One in three flocks tested have a significant proportion of Barber’s pole worms in recent worm egg counts. While rising one year old scouring merino lambs have been affected by thin-necked intestinal worms (nematodirus) or black scour worms.

Recent rainfall will improve the quality and quantity of feed for sheep, and help dilute the concentration of worm larvae on pastures. But conditions are now ideal for the hatching of barber’s pole worm eggs. Where in past years dung tests at this time of year have shown worm egg counts of a couple of hundred with ten or twenty percent Barber’s pole, some counts this year are a couple of thousand with 80-90% Barbers pole. You need to know whether Barber’s pole worms are present in your flock now, before significant pasture contamination occurs. A worm egg count and worm larval culture and identification on one or more mobs will be money well spent.

The value of checking worm egg counts after drenching was well demonstrated on one of our bigger properties. If not for a routine post-drench worm egg count, a serious problem with slow-release drench capsules used in ewes pre-lambing would have gone undetected. The ewes still looked well, despite carrying worm egg counts of a couple of thousand, yet still well within the expected pay-out period of the capsules.

Ram sales are in full swing, and it’s worth a bit of effort and expense to avoid importing drench-resistant worms with your new purchase. Check out the latest recommendations under Tests and Tools on this Wormboss website.

South-East LHPA

Bob Templeton, Braidwood, (

Not many WormTests this month.  However, barbers pole worm has been hitting young sheep across the Monaro.  This surprising when considering the very dry Autumn but I guess that dew and fog can take the place of rain.

Very recently did a PM on three dead cross bred ewes.  All died from Barbers pole worm.  Owner drenched with white/clear combo and white Extender capsules.  All ewes had young lambs at foot.  The lambs are growing well and ewes going down suddenly.

So not just young animals are being affected by Barbers pole worm.

Some black scour worm activity has been noticed with young sheep also affected.

My advice at present is to do a WormTest to see what each flock is carrying.  The results could be surprising.

North West LHPA

Fiona Fishpool, LHPA, Moree ( 

As predicted the moist Autumn and very mild Winter in the east of the North West LHPA district is leading to an early Haemonchus season.

A call regarding worm control advice for ewes and 3 to 4 month old lambs revealed lambs with exercise intolerance, pale eyes and a few with “bottle jaw” oedema.  Farmer is going to treat ewes with Avomec Dual, WEC weaners and ewes at 6 weeks and monitor frequently from there. Advice for those in the east of the district is to be vigilant as we could see a earlier than normal rise for Haemonchus. Monitor WEC and or use an effective long acting treatment at the start of October. In contrast, Spring Plains (just east of the Burren/Colly/Mungindi line) had negligible counts. In the west of the North West LHPA the dry autumn may not have allowed for much over wintering on pasture. Despite this it would still be wise to monitor WEC from the start of October.

Petrea Wait, Cooma. (

In the Cooma and Bombala regions producers are still doing some WormTesting, mostly on pregnant and lactating ewe mobs but also on sheep that are not doing well.  We are seeing some very high worm egg counts, particularly of Trichostrongylus ( Black Scour worm) and other scour worms, but minimal Barbers pole worms. One farm had counts ranging from 400 to 4240 eggs per gram, with 91% Trichs, another had counts from 40 to 2280 eggs per gram with 84% Trichs. Interestingly both farms had last drenched with products from the Mectin group – Abamectin and Moxidectin. Despite these results we did have one farm return a test with a zero worm egg count. With our recent good rains and very short pastures, now is a good time to be performing WormTests to determine if drenching is needed sooner rather than later.


Amy Shergold,( and Ian Masters, (

While worm egg count monitoring in Hume has been relatively quiet, the mild wet conditions are continuing to promote contamination of pastures. Young sheep are likely to need a drench, which for many will coincide with weaning treatments. One case of very high counts was reported in sick weaned lambs in Gerogery, average 2040 epg (range 40-7360) with a population of 100 percent black scour worm. This mob improved after drenching with an effective product.

On the whole, adult sheep are doing well; however there have been some variable burdens, for example in one mob of mixed ewes in Yerong Creek counts ranged from 0 to 3840 epg. It is, therefore, worthwhile repeating WECs on adult sheep every 6-8 weeks to assess the need for treatment. This may also assist in timing the summer drenching program.

In the Gundagai region, Barber’s pole worm has been responsible for light losses in young sheep on two holdings recently and a lot of larval differentiations over recent months are showing BPW at 50-70 percent of the worm population. If warm, wet spring conditions continue this parasite could cause problems much earlier than would normally be expected. Scour worms are active in the heavier stocked, higher rainfall districts where pasture growth was slower in late winter.

A case of liver fluke was seen in yearling cattle in Coolamon causing illthrift and bottle jaw. This farm had not had any problems with fluke previously; however the cattle had been bought in. This case emphasises the importance of considering where your stock are coming from and using appropriate quarantine drenching strategies.

Riverina LHPA

Gabe Morrice, Narrandera: (;

The WormTests received during the past month have shown a mixture of results.

Generally egg counts have been low, however in one case Dorper ewes had counts up to 3280, with an average egg count of 516 epg.

The larval diff in this case revealed 66% Haemonchus and 28% Trich.s.

With many farmers currently weaning or about to wean lambs, now is a good time to consider doing a Drenchtest to determine the effective drenches for individual properties.

Colin Peake, Hay; (;

We have received several wormtests in the last 6 weeks or so. Egg counts have been low for adult sheep, ewes, with average epg’s of 32 to 60.

But in 1 mob which was tested just before weaning, the ewe average epg was 40, while the lambs had an average of 1100 epg.

These lambs were drenched and weaned into a clean paddock.

This certainly shows the need and importance of WormTesting and that one of the most susceptible classes of sheep is weaners.

After the much needed recent rain, with sheep grazing close to the ground, the need to WormTest and drench test is now a very worthy consideration.

The previously reported Haemonchus that didn’t respond to moxidectin, responded to Levamisole and there certainly seems a high chance the resistance was caused from treating goats with Eweguard in the past. There are no more goats on this small premises now.

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