Back to State Outlooks

New South Wales worms, flies and lice update - May 2018

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Coonamble: Jillian Kelly, DV (


The extremely dry conditions have meant that sheep worms are not a big issue. Very few WormTests have been submitted from the Coonamble district with producers focusing on drought feeding stock.


A post mortem of a cow on a very poor plane of nutrition (being scrub fed kurrajong) last week showed a thickened abomasum indicative of Ostertagia (brown stomach worm). Drought affected cattle (both weaners and adults) will benefit from a drench.  Lice activity in cattle has not become prevalent yet due to the ongoing warm conditions. Producers looking to treat for lice once winter conditions kick in are advised to treat appropriately for both internal and external parasites at this time.

Dubbo: Evelyn Walker, DV (

I have been seeing a few cases of adult sheep affected by barber's pole worm this month. A variety of sheep producers from different areas have been affected including Dubbo, Peak Hill and Stuart areas. In these cases, adult sheep were dying with egg counts of 500 eggs per gram (epg) or higher which wouldn't normally cause a problem. These sheep were doing it tough under drought conditions and the lack of feed combined with an underlying worm burden tipped these sheep over the edge.

Let this be an important reminder that immunity to worms wanes when there is insufficient feed availability. Also when stock are concentrated in certain areas for feeding, this increases the risk of worm exposure. Consider checking at risk mobs with a worm test. Also be sure to use the correct dose rates for the weight of your sheep when drenching and add a safety margin to the withholding periods and export slaughter intervals for lean stock and those losing weight (Managing drought: Drought increases residue risk. NSW DPI. December 2016, page 16

The withholding periods listed on the label is the minimum time that must elapse before a sheep can be slaughtered for human consumption.

Forbes: Belinda Edmonstone, DV (

The dry still continues in the Forbes area of the Central West LLS with very few worm tests conducted. Nematodirus (thin-necked intestinal worm) is an internal parasite that does not normally cause major problems in this area. However, this worm produces a very drought-resistant egg and numbers can build up over dry times with mass hatching when it rains. This can result in losses in lambs and weaner sheep.


North West LLS

Northern Slopes:

Moree: Justine McNally, DV (

It is so dry out here. I think the worm issue is probably due to feeding stock in one spot where there is also some moisture from water troughs that is supporting some green pick and larval survival. Beyond that in paddock situations, I say good luck to any worm.  We could have an issue if we do get rain and fresh pick, as stock are stressed and in poor body condition, but time will tell.  


Murray LLS

Albury: Mark Corrigan, DV ( and Eve Hall, DV (


There have been a few WormTest submissions from the Eastern part of the Murray region over the past month. Conditions have been dry with the exception of a brief 10-25mm of rain experienced across the region in the second week of May. Submissions from a few mobs of pregnant and lambing ewes returned low to moderate egg counts of 140-360 eggs per gram (epg), reflecting some of the immune challenge that occurs in late gestation with the temporary loss of worm immunity. Larval culture from one mob of pregnant ewes showed a mixture of species, with barber’s pole and brown stomach worm most dominant.


A few reports of ill-thrift in young adult cows in the Eastern part of the region have prompted WormTests for Ostertagia and liver fluke. One scouring 2 year old first-calver had a strongyle-type worm egg count of 420 epg. On another property pooled samples for liver fluke ELISA indicated low to medium levels of infestation.

Producers should consider routine testing for liver fluke to help establish the infection status of their property. The two main tests include liver fluke egg counts on manure samples which help to determine whether the parasite is present, however it can sometimes be unreliable as fluke egg shedding can be intermittent, and liver fluke ELISA on blood samples which give an indication of the level of exposure to the parasite. 

April-May is the most important time for a strategic fluke drench in southeast Australia. At this time, burdens may be heavy and made up of a mix of adult and immature fluke. This means a triclabendazole-based drench (ideally an oral formulation and optimally triclabendazole plus oxfendazole) is the treatment of choice.


South East LLS

Braidwood: Kate Sawford, DV (

Lots of WormTests were received across the region in May. Results have been highly variable with average eggs per gram ranging anywhere from 0 to in excess of 3000. When larval culture has been carried out, barber’s pole worm has continued to dominate though we are now seeing more mixed infections and a couple of properties have had significant numbers of thin-necked intestinal worm

As winter sets in and daily maximums fall below 18 degrees centigrade, barber’s pole worm eggs will stop developing to larvae and will die, however, eggs from black scour and brown stomach worms can continue to develop as they hatch at lower daily maximum temperatures compared to those from barber’s pole worm - all the more reason to request a larval culture when you submit your WormTest. But note: barber’s pole worm larvae that hatched during warm and moist conditions in the last few months will continue to live on the pasture and infect the grazing sheep. New development of barber’s pole worm has stopped, but existing larvae can live for months, even during very cold weather.

If you’ve got winter lambing ewes it’s important to be mindful about where you put them. As things have been very dry, many producers were left with lambs well into autumn. Lambs often heavily contaminate paddocks with worm eggs that hatch in time for their larvae to infect winter-lambing ewes. Such paddocks should not be used for lambing.

Where requested, a few properties have had a number of liver fluke eggs detected. Remember one way that testing for liver fluke differs from testing for roundworms in the gastrointestinal tract is that even one fluke egg is significant. Now that we have had a few frosts it’s time to drench sheep on affected properties with a product containing triclabendazole, the only drug active against all stages of the liver fluke in sheep (products for cattle differ slightly). Interestingly, one property in the region that did some blood testing in cattle for liver fluke showed a high level of challenge even though they had been drenching for fluke annually in May after the first frosts for many years. It may be that cattle have been intensively grazing some areas that were heavily contaminated with the intermediate grass stage of the fluke as these have been the only areas containing green pick in the face of the dry conditions. The producer was recommended to do the May drench as per usual but also an August liver fluke drench to remove any flukes that may have infected the animals over winter. As winter is typically cold enough in this region to prevent reinfection in late winter, a drench that controls only the adult stages will be suitable in August.


Greater Sydney LLS

Penrith: Nigel Gillan, DV (

The reality is that there isn't much to say on parasites in Greater Sydney at the moment due to dry conditions.   

Western LLS

Broken Hill: Felicity Wills, DV (

Again this month the season has remained very dry in the Western LLS, reducing the survival of larvae in the environment. A lot of producers are now confinement feeding sheep and cattle and so exposure to worms is increased particularly with some stock being in poorer condition. Three sets of faecal testing have been conducted in the Western region: two tests in the Bourke area from mixed aged and sex flocks showing some signs of scouring, revealed low numbers of worms with a high percentage of scour worms. The third test was on a flock of mixed age merino ewes being confinement fed. Some scouring had been identified in this flock as well. These ewes had moderate to high faecal egg counts with a high percentage of scour worms.

These results suggest that faecal testing (WormTest) maybe beneficial in flocks in the Western region, despite dry conditions, particularly if they are being confinement fed, or signs such as scouring or ill thrift have been identified.

For May 2018 state outlooks, please follow the links below:
Back to State Outlooks