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New South Wales worms, flies and lice update - March 2020

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Coonamble: Jillian Kelly, DV (

The Coonamble district has experienced good, general rainfall in recent weeks and temperatures are mild—the perfect weather for barber’s pole worm to flourish. While WormTests have not yet shown high counts, and no clinically affected sheep have been seen, producers are urged to be on the lookout in coming weeks as burdens are expected to rise and may catch people unawares. Nuisance fly burdens are high with reports that stock are really tormented by them. Some producers are reporting reduced weight gains due to the constant fly worry. This is especially an issue in sheep feedlots that are still continuing to operate. The mosquitos that have arrived in force since the rain have brought Bovine Ephemeral Fever (or Three-Day Sickness) to cattle herds in the district. Sheep producers are advised to check sheep daily for flystrike as the conditions are perfect. For more information about how to manage risk, producers can visit and enter their specific flock details and conditions to get some good advice about options for flystrike management and prevention.

Forbes: Nik Cronin, DV ( and Belinda Edmonstone, DV (

Over the past month we have had multiple rain events and milder weather conditions that have allowed pasture growth in our district. We recommend that producers use WormTests to monitor worm burdens in sheep at this time. These conditions are ideal for barber’s pole worm, and populations can build up quite quickly and cause significant disease. This worm is a blood feeder, and in large numbers, causes sheep to be anaemic and weak. Sheep in which barber’s pole worm burdens build up quickly can be in good condition, but may go down when pushed, such as during mustering.

Flystrike may also be an issue now, and producers should be monitoring for affected animals. FlyBoss tools is an excellent resource to use to examine fly control strategies.

Nyngan: Erica Kennedy (

The last rain event in the Nyngan district was nearly two weeks ago and we are anticipating high barber’s pole worm burdens to begin to impact sheep over the next few weeks, especially given the recent mild temperatures. The WormTests that have been carried out have not yet found any worm burdens (remember the life cycle takes 3 weeks from egg to adult) and no clinical cases have been reported thus far. Producers are encouraged to keep monitoring worm egg counts and look for signs of worm infestation in their stock. If drenching is required, please use a combination drench to reduce resistance and be aware of local moxidectin resistance, as shown in trials back in 2013. Drench resistance testing can be undertaken at this time (a DrenchTest should be performed every 3 years). You will require undrenched weaners with worm burdens >500 epg for the test. Information on how to conduct a DrenchTest can be found at

Producers who are restocking are urged to consider the risk of introducing drench resistance. Contact your local vet for more information and refer to WormBoss for the resistance status of drench groups throughout Australia. 

Flystrike is still prevalent, and you are urged to continue to check your sheep daily (or at least every second day). Treatment, when needed, is encouraged, but preventative measures can also be pursued i.e. crutching or shearing when appropriate. For more information on how to manage the risk or solve your current flystrike problem, visit Preventative measures for insects, such as flies and mosquitoes, might be considered (especially for cattle) with large numbers of cases of Bovine Ephemeral Fever (Three-Day Sickness) being reported throughout the region. Please speak with your local District Vet or private vet in regard to BEF prevention and treatment. 

Murray LLS

Albury: Mark Corrigan, DV (

Holbrook: Eve Hall, DV (

Deniliquin: Linda Searle, DV (

General, good rain, early in March (between 50 and 120 mm), across the Murray Local Land services district, brought a smile to everyone. Warm temperatures, soil moisture and lack of ground cover has led to an abundance of summer weeds with caltrop (cat’s head) rearing its ugly head in places not seen before. No clinical disease has yet been identified, but with hairy panic and heliotrope across the cropping area of the district, it is likely that there will be some sheep that will suffer photosensitisation.

On the worm side there have been limited WECs in the last month. The few results that we have had all showed nil, or low, worm numbers. In the western part of the region, a larval culture showed our normal scour worms were present (99–100% black scour worm, 0–1% brown stomach worm). At time of writing, there were no reported cases of barber’s pole worm, which is a blood feeding worm. Due to the early March rain, it is important to continue to monitor your sheep for worms. This allows strategic drenching to take place if needed. Due to the dry spring in parts of the region, WECs may be relatively low.

South East LLS

Braidwood: Lou Baskind, DV (

Braidwood has been blessed with significant rainfall, and the autumn growing conditions have seen pasture plants jump ahead. Our first rainfall event was in early February, with another decent event at the start of March securing our Autumn break. The average minimum temperature for February was 13.6 ? which exceeded our mean by 1.3 ?. These warmer-than-average overnight temperatures are driving rapid and lush autumn pasture growth. Unfortunately, these warm and moist conditions are also perfect for worms. Mid- to late-March will likely see some significant impacts on livestock due to intestinal parasites. 

Prior to the autumn break, our pasture heights were abysmal, and even with this rapid autumn growth, livestock are still grazing in the worm zone, which means they will be picking up any larvae available. The worm zone is from the base of the plant up to around 10 cm–15 cm. 

Worm egg count results from mid-February showed very low worm egg numbers, particularly for sheep that had been confined in drought lots and fed from raised feeders, or moved onto clean pasture after their last drench. Nematodirus (thin-necked intestinal worm) was still present in moderate numbers in lambs, having survived the dry conditions. Our highest WECs in February were lactating goats with 400 epg and dry ewes with 900 epg. By early March, a mixed class group of set-stock sheep had a WEC of 8000 epg! 

The water crisis experienced through summer also exposed more fluke cysts to animals grazing close to edges of springs and dams. The drop in water level allowed more access to these cysts. One property was tested in early March and fluke eggs were detected in four out of five samples, and fluke ELISA blood tests showed high level of infection across the herd.  

All sheep managers should be doing WormTests now! During these warm and wet conditions, test every 4 weeks. All cattle should be drenched in autumn for liver fluke. I usually recommend this drench closer to the end of autumn, allowing for a “cleanout” of fluke just before the cold weather causes the snail to hibernate. For Ostertagia, calves should be drenched at weaning and all young cattle drenched during autumn. 

Western LLS

Bourke: Charlotte Cavanagh, DV (,

Buronga: Trent McCarthy, DV (trent.mccarthy

Broken Hill:  Jess Van de Weyer, DV (

Though only a few WormTests have been submitted in this region recently, landholders in the Western region of NSW have been reminded of the importance of doing their homework following recent rain events in some parts of the region. This includes performing worm egg counts (WEC) prior to drenching. Producers are also reminded to quarantine drench new or introduced stock originating from other regions.

Where producers use confinement operations, WECs prior to drenching have proven especially rewarding. This was shown when the results of a single WEC, submitted as part of a disease investigation from such an operation in the western region, identified differentials (i.e. coccidiosis/salmonellosis) mimicking parasite burden, were the culprit.

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