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New South Wales worm update - November 2013

Rad Nielsen, Veterinary Health Research, Armidale (

Worm monitoring results at VHR over the last month have been quite mixed. Some sheep producers are finding that the worm situation is quite contained after a very dry start to Spring, whilst others are encountering high worm challenges from overwintering larvae (in what were high contamination paddocks last Autumn). Haemonchus is the predominant worm species being seen in the New England at this time.

Failure of drenches is also being detected on a regular basis. Levamisole and moxidectin resistance is widespread now in respect to Haemonchus and naphthalophos mixtures not uncommonly have reduced efficacy. It is very important that graziers establish the drench resistance status on their properties and be mindful of this when formulating drenching programs.


Lachlan LHPA

Belinda Edmonstone and Nik Cronin, Forbes (  (

In the central area of the Lachlan LHPA there were only five WormTests performed for the month of October with average faecal egg counts ranging from 40-1032. Individual counts range from 0 – 3280. Generally worm egg counts remain low as the dry conditions continue. Pastures have well and truly hayed off so now is the time to start thinking about using a broad spectrum combination drench as the first summer drench onto a low risk paddock. If you have any doubts WormTest.

Kasia Hunter, Condobolin (

In the western area of the Lachlan LHPA three WormTest results were received during the past month. All demonstrate nil or low levels of parasite infection.

Two out of three tests were assessing drench efficacy with faecal samples collected 2 - 3 weeks post-treatment. In both cases (on two separate properties), no evidence of drench resistance to Nucombo Oral (Merial) was observed.

The third WormTest assessed a mob of adult lactating Dorper ewes. The average Strongyle egg count in this mob was 120 epg. The larval differentiation demonstrated a mixed infection consisting of: 65% Haemonchus (Barber’s Pole Worm), 26% Ostertagia (Small Brown Stomach Worm), 5% Trichostrongylus (Black Scour Worm), 4% Oesophagostomum (Large Intestinal Worm) and 1% Cooperia (Small Intestinal Worm).

The time for the first Summer drench has well and truly arrived, as pastures have ‘hayed off’ around the district. Many producers have treated their stock already. It is important to select an effective broad-spectrum drench for this important strategic treatment.

Significant variation can exist between properties in relation to the worm burdens of their livestock. If you are unsure of the status of your sheep conduct a WormTest.

Elizabeth Braddon, Young (

The Young area has been very quiet on the worm front.  The usual level of testing has occurred but is not yet compiled due to the Avian Influenza outbreak.  However, no enquiries or clinical cases have been reported.  Most producers are either looking at doing the first Summer drench or have done so already combined with a weaning drench for Spring lambs. 

With the rainfall we are having at the moment, we could see increased worm activity in about three to four weeks.  This is particularly the case for Barber's pole worm if the weather warms up a bit after the rain. 

If you haven't thought about your first Summer drench yet, then a WormTest with a larval culture would be recommended in the coming weeks, to ensure you and your flocks are protected moving into Summer.

Central West LHPA

Evelyn Walker, LHPA DV, Dubbo (

Worm levels vary across the Central West. No deaths this month have been attributed to Barber’s pole worm. However, sheep mobs throughout the Central West including surrounding areas of Dubbo and Gilgandra are showing medium to high worm burdens in not just weaners but even in dry ewes.

Don’t be fooled by this dry season we are currently experiencing. When there is lack of feed or poor quality pasture, the sheep’s immunity to worms and disease goes down.  Also, if you are hand-feeding, remember worm levels can build up at concentrated feeding points so try to vary your feeding locations.

It is also important to remember that the Barber’s pole worm is capable of lying in wait inside the sheep’s gut and when environmental conditions are right or when sheep have lowered immunity, she strikes.

And no I’m not talking about the in-laws. At least with worm egg count monitoring, you have some time to prepare!

South-East LHPA

Bob Templeton, Braidwood, (

Beautiful rain last week and no reports of worm activity as yet.  Expecting more rain soon so the worms should start moving again.

Petrea Wait, Cooma (

In the Cooma and Bombala regions only a few WormTests have been conducted. Egg counts have been variable ranging from zero to several thousand, and in those that have done differentials we are seeing only scour worms. Interestingly, those that have drenched with single active drenches, particularly Cydectin have had high counts, while those that have used combination drenches have had low counts.

Now that we have had some very good rains in the district, combined with warm conditions, the Barbers Pole worms will be rearing their ugly heads. Now is the time to be conducting your Summer drenches, if you haven’t done so already. WormTesting is recommended prior to drenching to identify the level of infection and the need to drench, and the type of worms present to tailor your drench selection. If you are not worm testing, then a combination drench is recommended.

Tablelands LHPA

Bill Johnson, Goulburn, (

Parts of the district received substantial rainfall in the past couple of weeks, sufficient to promote hatching and survival of Barber’s pole worms. We know from recent worm egg counts that Barber’s pole worms are present on about a third of properties. Even if you have already done your first Summer drench, and the drench used was effective against Barber’s pole worms, you cannot afford to be complacent. A worm egg count and culture on key mobs before Christmas would be worthwhile, and reassuring.

Black scour and brown stomach worms have been responsible for high worm egg counts in young sheep on several properties. Where green feed is still available, these young sheep are scouring. Where there is only dry pasture, scouring may not be present. Remember the importance of good nutrition on the ability of young sheep to cope with worms. Weight loss in weaner sheep is associated with a high risk of dying.

Don’t forget to include the rams in your Summer drench program. It is surprising how often they miss out, causing them to be below par at joining.


Tony Morton, Wagga Wagga. (

As expected most counts revealed black scour worms and small brown stomach worms. Fortunately these are the two worms the two Sumer drenches of Drenchplan best control. With most of the district haying off, the first Summer drench should be given now if it hasn’t’ already been given. Some counts also revealed Barbers pole worms and where that occurs extra monitoring in Summer is wise, say 6 weeks after the most recent drench.

The value of regular monitoring was demonstrated when two mobs of ewes with negligible counts in early June were monitored again. The counts were 1,200 e.p.g and 1,800 e.p.g despite the sheep appearing healthy and the larval identification showed 75% black scour worms and 25% Barbers pole worms. Immediate drenching has removed the black scour worms that will have been causing sub clinical production loss and reduced contamination by Barber’s pole worms which can otherwise build up extremely quickly with the right Summer conditions. The finding of Barber’s pole worms is a timely warning as to the potential risk of Barber’s pole worms if we get a wet Summer.

A drench resistance trial completed on a farm in Tarcutta revealed resistance/ suboptimal efficacy in the small brown stomach worm to Ivomec, Cydectin, Rametin combination and a white/ clear combination. A drench program was developed for this operation, including the use of effective drenches – abamectin/ white/ clear triple combinations and monepantel (Zolvix) – and the use of ‘Smart Grazing’ to reduce larval contamination of pastures at weaning time. Smart Grazing involves intensive grazing with 2.5-3 times normal stocking rates for < 30 days after an effective first and second summer drench to prepare weaning paddocks. The clean pastures are then destocked after the intensive grazing period to allow re-growth. Further information on Smart Grazing is available on this site, link:

Riverina LHPA

Dan Salmon, Deniliquin (

The southern part of the Riverina LHP district has had a modest number of worm egg counts, particularly at a time when the decision about late Spring drenching should be made.

What counts have been done are mixed although mostly low.

One feature is the continued low Nematodirus egg counts. Nematodirus is usually a grand survivor in the western Riverina but several years when the sheep have been eating more grass and less dirt seem to have reduced their numbers significantly

North West LHPA

Fiona Fishpool (

Despite the dry weather for most of the North West district we are seeing pockets of Haemonchus in areas that experienced a wet Autumn.  Worm egg count’s as high as 4080 epg in weaners and 9000 epg in ewes on one property also highlighted closantel and moxidectin resistance. This effectively knocks out sustained action drenches for this property. Producers are advised to conduct drench checks routinely to ensure they know what drenches work. Other areas west of Moree and Narrabri have had negligible worm egg counts.  As it is currently raining (may it continue) it would be wise to monitor WEC and consider treating if an effective long acting treatment was not used in October.

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