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New South Wales worms, flies and lice update - May 2019

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Coonamble: Jillian Kelly, DV (

Very few WormTests have been conducted in the Coonamble district. There have been two decent falls of rain in some parts of the district since late March, and temperatures have remained warm, so there is a risk of larval infections and increasing worm burdens at this time. Producers are urged to WormTest, especially just before lambing. Allow enough time to get the results back, make a decision, and then drench (if necessary) a good few weeks pre-lambing to avoid pregnancy toxaemia.  For these reasons, therefore, producers should do a WormTest 6–8 weeks pre-lambing.  

It has been almost 8 years since Coonamble producers had the right conditions to perform Faecal Egg Count Reduction tests (or DrenchTests) in weaner sheep. If it rains through winter and into spring, producers should bear in mind that conditions will be suitable to test and this will be a great way of assessing what drench actives are working on your farm, so don't just reach for the drench gun in weaners, consider doing a trial first. For more information, contact your District Veterinarian.

Sheep blowflies are remaining active due to the warmer than usual conditions and some rainfall.  Producers are encouraged to do resistance testing on any maggots they find.  Look here for details about the free test worth over $3000.

In cattle, there have been no signs of lice in any stock examined lately, again due to the unseasonably warm weather.  Producers are urged to consider drench efficacy when treating for lice this year and not just reach for the cheapest backline product.  Small black flies remain active, and there is still pink eye being observed in some mobs.

Riverina LLS

Young: Evie Duggan, DV (

In the Young area, the majority of worm egg counts have been low–moderate, but there were a handful of high counts that required immediate drenching. Most of these high worm egg counts were in ewes towards the end of gestation and in ewes post-lambing.  With counts of over 2,000 eggs per gram (epg) it was assumed they were a result of Haemonchus contortus (barber’s pole) burdens.

A reminder again of the importance of a pre-lamb drench and pasture management as disease and deaths can be caused by a heavy barber’s pole burden in ewes with lambs-at-foot.

Many properties in the area have the opportunity to drench onto crops that provide clean grazing for lambing. It is important to remember that once a pasture has a worm larval burden on it, those worm larvae (barber’s pole) have been shown to be able to survive through the Young winter conditions. With this in mind, it is important to consider your paddock rotations, and drenching low–moderate worm egg counts (WECs) to prevent contamination from building up in the paddock. The length of pasture and grazing crops will play into our favour, as a height of over 10 cm will reduce the volume of infective larvae ingested by grazing sheep.

Some properties have had slow growth of grazing crops and pasture, meaning that they will not be ready to graze when the ewes are due for their pre-lamb drench. In these cases, depending on the WEC, it may be worthwhile considering a long-acting drench for specific mobs, with a priming drench. This means that the worm burden currently in the ewe is killed and the long-acting drench prevents the ewes picking up more worms and taking them onto the clean grazing crop/pasture when it is ready to be grazed. Please contact your district veterinarian if you would like to discuss your worm egg count report or if you wish to discuss a plan. 

Narrandera: Sophie Hemley, DV (

The mid and western Riverina has had limited numbers of worm egg counts submitted over the previous month. Many producers have lambing ewes and many have been busy with sowing. Worm tests should be considered opportunistically if you have sheep in the yards for marking, or if you still have sheep being confinement fed, consider undertaking a WormTest

Northern Tablelands LLS

Inverell: Andrew Biddle, DV (

No rain. No worms.

Joining is well underway. Condition of ewes and rams is hugely variable and resulting conception rates will mirror this. The best advice is to scan and target diminishing feed to pregnant ewes and assess the cost-benefit of retaining empty ewes.

Managing feeding of lambing ewes in drought-lots will become the next challenge.

North West LLS

Northern Slopes: Ted Irwin, DV (

Not many sheep are left in this area at present. WormTests were last conducted about 12 months ago, and no sheep autopsies have been performed for a few months either.

There is still a lot of variability in ground cover from property to property and worms are probably still active in areas where there is some short pick about. At present, though, people have really been battening down the hatches. The last sheep sale at Inverell had around 6000 sheep (that's big for this area) so there's a fair bit of offloading in progress. It is estimated that the big producers in the area have sold down to about 30% of their peak numbers.

Murray LLS

Albury: Mark Corrigan, DV (

Holbrook: Eve Hall, DV (

Deniliquin: Scott Ison, DV ( and Linda Searle, DV (

Much (but not all) of the eastern end of the Murray region has experienced a later Autumn break this year with rainfall of 35–60 mm recorded in the first week of May, some getting follow-up rain of up to 20 mm a week later. This moisture, combined with mild temperatures, morning dews, and potentially heavy grazing of short green pick means that conditions are currently ideal for worm activity to be on the rise. Autumn lambing ewes are particularly at risk given the reduction in worm immunity that occurs in late gestation. Deciding on an approach to drenching late pregnant ewes depends on numerous factors: efficacy of your summer drenching program, current worm burden (WormTests), and availability of low-risk lambing paddocks. The online WormBoss drench decision guides and your District Veterinarian are your best sources of information. Some general recommendations:

  • WormTest—avoid unnecessary drenching.
  • Use effective drenches and multi-active combinations where possible.
  • In general, use short-acting drenches and restrict the use of long-acting drenches only for specific purposes.
  • If the use of a long-acting is deemed necessary, don’t forget the need for primer and exit drenches.
  • Calibrate your drench guns, dose to the heaviest sheep and follow label instructions.

The western end of the Murray region is still quite dry at the moment and consequently, there have been no reports of worm-related losses at this time. This is reflected in the few WormTests that have been submitted recently. A mob of pregnant ewes which were last drenched in April 2018 with a quadruple combination of abamectin, albendazole, closantel and levamisole, showed an average count of 60 eggs per gram (epg) strongyle type.

South East LLS

Braidwood: Lou Baskind, DV (

Around Braidwood, local producers of sheep and goats have been struggling with an extended barber’s pole season. Despite a first frost on the 27th of April, temperatures have remained warmer than average. Daytime temperatures have been well above 12 degrees Celsius (average 17.7°C for all of May, and 21.2°C for April), allowing worm eggs to develop into infective larvae. Rainfall has been less than half the usual for May, but a few small showers, fog and mist have provided enough moisture. These conditions, combined with the short pasture length of perennial grasses, have allowed barber’s pole to persist.

Signs of barber’s pole have been seen in lactating ewes and weaner lambs, including bottle jaw, anaemia, weakness and deaths. Sheep and goats suffering poor body condition and/or poor nutrition have been affected by both barber’s pole and black scour worm. Barber’s pole is affecting mostly set-stocked paddocks, with problems recurring 6–8 weeks after drench treatments. Unfortunately, the use of rested, clean pastures for worm management has had to take a back seat to feed availability due to drought.

A reminder that the worm egg count is an objective tool but needs to be interpreted in context. For example, this month we had a worm test in a mob of dry maiden ewes and the average strongyle egg count was 1600 eggs per gram (epg). That mob was showing no observable signs of ill-health; on the other hand, a mob of late pregnant goat does, set-stocked on short pasture had a count of 450 epg but were experiencing anaemia, weakness and deaths. Your district veterinarian is available to assist you with the interpretation of worm egg counts. The worm egg count is a valuable tool, but not the only factor in management decision making.

Berry: Evelyn Walker, DV (

We have seen some high sheep worm egg counts in the Wingecarribee and the Shoalhaven shire areas. A variety of signs have been observed by producers including sudden death and lethargy in both good and poorer conditioned ewes and lambs. In all cases, no signs of bottle jaw were observed in affected flocks. Let this be an important reminder that sheep may not always read WormBoss and give you all the typical signs of barber's pole worm infection.

Editor’s note: Visual signs of infection only occur after significant blood loss, and therefore production loss, has already occurred and bottle jaw does not always occur with barber's pole disease.

At the moment, the majority of cases have been due to barber's pole worm. It is important to monitor your flock with regular worm tests to catch problems before they arise.

Editor’s note: WormTest counts the number of eggs released by mature female worms into the dung pellets. Since immature worms do not produce eggs (but do suck significant quantities of blood) they are not detected until they mature, making follow-up worm testing every 3–4 weeks in showery weather, very necessary.


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