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

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides





Coonamble: Jillian Kelly, DV (

The Coonamble district has continued to experience regular falls of rain, which is quite exciting following the dry past three years.  This rain, combined with warm temperatures, has seen some mild increases in barber’s pole worm burdens in sheep across the district, as indicated by worm egg counts performed by NSW DPI laboratories.  While most of these burdens are not in the range of needing a drench, the larvae are likely to survive on the pasture over winter, and become an issue in spring and summer.  Producers are asked to be mindful of this, and to do a WormTest now to establish burdens heading into winter, and importantly, what species of worms are present in their flocks.

Recent post mortems of weaner steers in the district (who died of other, varied causes) showed that their abomasum was affected by the larval stages of Ostertagia.  This is likely having a production effect, and producers who are running young cattle are reminded that they will require an effective drench.

Fly burdens are reported to have reduced following the cooler temperatures as we head into winter.

Northern Tablelands LLS

Armidale: Amanda Walker, DV (

Conditions have dried off and winter is fast approaching the Northern Tablelands, however we continue to see sheep affected by barber’s pole worm and remind producers that the risk is not over yet.

Some mobs have had significant worm burdens present even soon after drenching, suggesting that drenching was not effective. Where this occurs it is critical to review the drenching protocol and to check drench efficacy on the property. Drench efficacy can be assessed through a quick DrenchCheck—a WEC performed 14 days after drenching; or the more comprehensive DrenchTest that assesses drench resistance to multiple individual drench actives. The information from these tests can help producers choose effective drenches and to manage the development of drench resistance.

Murray LLS

Albury: Mark Corrigan, DV (

Holbrook: Eve Hall, DV (

Deniliquin: Linda Searle, DV (

Early autumn rain and above average temperatures across the east of the region has seen good pasture growth. Conditions are highly conducive to worm activity. Pregnant 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 vet or livestock advisor can be of assistance here. 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-actings 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.

Cattle 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 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 generally considered the most important 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.

Worm issues are not being reported in the western end of the area at the moment. Worm test results are minimal with the few that have been done showing low results: A group of sheep treated back in July last year with a long acting injection showed only an average of 36 epg and low levels of coccidiosis. Another property had mixed age pregnant ewes with no drench history with an average count of 80 epg. They also had a mob of 10 month old merino ewes with no drench history that had an average worm egg count of 220 epg. This was found to be 1% barber's pole worm, 94% black scour worm and 5% brown stomach worm.

In the eastern end of the area worm egg counts have generally been low. One flock that requires on going monitoring every autumn for Haemonchus indicates moderate levels, but larval cultures have shown black scour worm as the dominant worm.

For May 2020 state outlooks, please follow the links below:
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