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New South Wales worms, flies and lice update - January 2021

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Condobolin: Hanna Thomas, DV (

Very few WormTests have been conducted recently in the Condobolin district. However, from the few that have, some high Nematodirus counts have arisen, with one individual count coming in at 920 eggs per gram (epg) (this was coupled with a high roundworm count). 

Nematodirus is generally not a problem in adult sheep but can be seen to cause some issues in young sheep. Signs include scouring, lethargy and weight loss. Problems tend to arise after dry spells when sheep graze short green feed, or when sheep are stressed.

In young lambs and kids, a worm egg count of over 200 epg would require treatment.

Coonabarabran: Kate Atkinson, DV (

As the rams are going in with the ewes, now is the time to start planning ‘clean’ paddocks for lambing ewes and weaners. Paddocks generally require a six-month period of rest from grazing sheep or goats to be considered a low worm-risk or ‘clean’. This is at least a 95% reduction of worm larvae on heavily burdened pastures.

Lambing ewes and weaners are particularly susceptible to worm infestations due to their immunocompromised state. Providing ‘clean’ lambing and weaner paddocks (in combination with worm egg counts and strategic drenching) will help lower the spring barber’s pole worm populations resulting in lower morbidity, mortality and production loss.

Sheep lice are about and can be introduced when restocking. Lice are almost solely spread from sheep-to-sheep contact. Therefore, if restocking, be sure to adhere to your on-farm biosecurity measures and quarantine new sheep for a period of 2–4 months after an off-shears treatment before introducing to your flock. Thoroughly inspect sheep during this period for parasite and health issues in order to reduce the risk of introducing lice and other problems.

Dubbo: Sarah Maher, DV (

We are seeing barber’s pole worm continue to cause issues due to continued warm, moist conditions. Many producers have been calling to seek advice on drenching post-worm testing and several unlucky producers have seen diarrhoea, production losses and deaths in their flock due to high barber’s pole worm burdens and concurrent scour worm. There have also been a few cases recently where drenches have not worked (i.e. drench resistance is present); these cases have caused farmers additional grief as not only have they had to buy more drench, but their previously ‘clean’ paddocks are now contaminated with barber’s pole worm larvae. This is where drench resistance testing (or at least a DrenchCheck) is important, so we know we can select an effective drench that will get the job done.

After what has been a wet, warm summer (perfect for barber’s pole worm), farmers need to be thinking about lambing paddocks; the scorching summer days didn't arrive so eggs and larvae on pasture would not have died as quickly creating pastures with high worm burdens.

WormBoss has a good resource on preparing low-risk lambing paddocks.

Forbes: Nik Cronin, DV (

Producers in the Forbes district are reminded to keep monitoring their sheep for worms this season! Lambs should have been given a drench at weaning. In a number of cases we have seen problems and production losses in weaners who have not yet been drenched. These have been mostly related to mixed burdens of both barber's pole worm and scour worms, and the lambs have improved markedly following the administration of a good, effective drench. For all other classes of sheep, WormTests are invaluable to determine whether or not a summer drench is required. WormBoss has an excellent tool in the Drench Decision Guide that producers can use to assist in making the call on whether to drench or not.

Nyngan: Kelly Wood, DV (

The rain over the Christmas period means that the risk of barber’s pole worm continues to be high in the district. Barber’s pole worms are egg machines, with females pumping out up to 10,000 eggs per day. This means that larval burdens can build up and rapidly result in fatalities under ideal conditions. If you weren’t able to prepare low-risk paddocks for your weaners this year, it will be very important that you are using effective drenches and carefully monitoring your young stock for signs of worms. This should include regular WormTests (checking at least every 4–6 weeks after administration of a knock-down drench). Visual signs of infection (such as bottle jaw and paleness of the gums and inside the eyelids) only occur after significant blood loss has already occurred. If the sheep collapse while you are trying to catch or move them, you likely have a worm problem and should treat these sheep immediately with an effective drench where they collapse in the paddock; carry drench or go back and drench them rather than stressing them more with transport to the yards. If you have not conducted a DrenchTest in the last 2–3 years or have purchased a large amount of stock since then without appropriate quarantine drenches, and you are unsure about the efficacy of the products you are using, consider conducting a DrenchCheck. Under these high risk conditions, monthly WECs are indicated. Instructions for how to conduct a DrenchCheck and pictures of the clinical signs of barber’s pole infection can be accessed via the WormBoss website.

The continuing wet weather also represents an ongoing risk of flystrike. Targeted monitoring of high-risk stock, early detection and effective treatment of strikes helps not only manage the fly burdens on your property but can also help slow the development of resistance. For more information on mitigating fly risk on your property, visit the FlyBoss website.

Murray LLS

Albury: Mark Corrigan, DV ( and Brianna Henman, Charles Sturt University

Now that the busy season of harvest has concluded for many across the district, it is important to re-check your stock for the presence of worms. Recent WormTests for the eastern Murray region have shown high worm burdens, in particular black scour worm. A recent investigation into lamb deaths revealed an average worm egg count of 4,182 strongyle eggs per gram, with larval culture indicating 88% black scour worm, and the remaining 12% brown stomach worm. These lambs had last received a drench at weaning in July. This emphasises just how important it is to conduct regular WormTests to determine the presence and nature of any worm burden in sheep on your property. In the case mentioned, the affected mob was then drenched with a combination drench containing moxidectin, levamisole and albendazole and no further losses were experienced.


Another thing to be on the lookout for at this warm time of year is anaemia. The clinical signs related to anaemia include collapse, weakness, pale gums, and death. These signs are most pronounced during stressful periods, such as lamb marking and mustering of young, affected sheep. The most common causes of anaemia in sheep include barber’s pole worm, liver fluke and the bacterium Mycoplasma ovis. Recently, a case of M. ovis was detected in the eastern Murray region, that resulted in six affected ewes. M. ovis can be spread via infected blood on equipment during lamb marking or via blood sucking insects such as mosquitoes, that are active during this summer period. If you have sheep showing signs of anaemia, it is prudent to perform a WormTest on the mob prior to mustering to help differentiate between barber’s pole and M. ovis. With this information in mind, your veterinarian will be able to assist you in deciding on the safest management action to prevent further losses.


Both the east and west have recently diagnosed some sporadic cases of pneumonia. Pneumonia can present as panting and coughing at the tail end of the mob, especially after being moved, or as sudden deaths. Investigations into the recent cases have revealed that major husbandry events, such as dipping and shearing, have initiated the outbreaks. Therefore, it is a good time to review preventative measures for pneumonia. These include reducing dust in the yards, minimising stress, having a good drenching and dipping technique to avoid liquid entering the lungs, and carefully monitoring sheep after transport.

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