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

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides






Central West LLS

Coonamble: Jillian Kelly, DV (

Very few worm tests have been performed in the Coonamble district. It is expected that sheep parasite burdens will be low due to the ongoing dry conditions. 

Cattle that were suffering from poor nutrition were found to be carrying Ostertagia sp (brown stomach worm) burdens on post mortem examination. This is a timely reminder to producers to ensure stock nutrition is good, and a drench for adult cattle as well as weaners may be warranted. Producers are reminded to make use of combination drenches in both sheep and cattle. 

Fly strikes have reduced due to the cold, dry weather but flies will re-emerge in spring. Producers should consider a multi-faceted flystrike management program rather than reach for a chemical. can help with this.

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

The few worm tests performed in the Forbes area of the Central West LLS have generally had low egg count results. There have, however, been a few moderate counts due to the thin-necked intestinal worm (Nematodirus). The eggs from these worms are particularly resistant and will survive dry spells. The worm does not usually cause disease in adult sheep as they will have strong immunity. It can, however, cause disease in young lambs and any with an egg count greater than 200 eggs per gram should be drenched.

Editor’s note: immature Nematodirus (thin-necked intestinal worm) worms can cause scouring and deaths in weaners, particularly after summer storms, and before they mature and produce eggs into the dung.

Riverina LLS

Young: Eliz Braddon, DV ( and Evie Duggan, DV (

There have only been a handful of worm egg counts (WECs) come through over the past month for the Young area. The counts have been highly variable and are reflective of the scattered showers and different stages of flock management. Due to this variation, generic advice is not appropriate this month, except to advise producers to start carrying out WECs in the first 2 weeks of August to establish the worm burden in their flocks.

Currently, the focus is on the management of pregnant and lambing ewes. The post-parturient rise in WECs makes a pre-lambing drench and pasture management important. If there is a worm burden present in ewes during lactation this not only has negative effects on the ewe, but also directly affects the productivity of the lambs—with decreased milk produced by ewes and a higher burden of infective worm larvae on the pasture. Lambs (<12 months of age) have not yet developed immunity to worms, meaning that they are much more susceptible to worm burdens and worms can produce more eggs. Ingestion of low numbers of infective worm larvae has been shown to cause a 50% reduction in weight gain and decrease wool growth by up to 30% in 12-month Merinos and 18% in 2nd cross (X) lambs. It is important to note that it is not recommended as a routine practice to drench lambs in the cradle at marking unless there is a high risk of Nematodirus infection (this year is not providing high-risk conditions). Seek professional advice.

Northern Tablelands LLS

Armidale: Amanda Walker, DV (

As a result of the continued dry conditions, there have been few worm tests conducted, and only low worm burdens have been reported. At this time, the priority for most producers is to ensure they can adequately meet the nutritional requirements of their stock. Current advice is to ensure a balanced ration when supplementary feeding to prevent conditions such as urolithiasis and acidosis that are being reported more frequently in the region. 

Inverell: Andrew Biddle, DV (

It’s a pretty hostile environment out there now for worms and sheep. There haven’t been any requests for worm egg counting, presumably due to the ongoing dry weather. 

A few early mobs of ewes are starting to lamb and cows are starting to calve.

There have been cases of recumbency and dystocia due to low blood calcium. In some cases, this may be the result of animals on cereal grain or white cottonseed have not had calcium added to the diet, and in others, it’s due to mixing or animals accessing loose mixes. There has also been a spike in urolithiasis in wethers, particularly in animals feeding on diets based on cereal grain, white cottonseed or dried distillers grain that do not have a balanced the Calcium/Phosphorus ratio. 

South East LLS

Yass: Fiona Kelk, DV ( and Alexandra Stephens, DV (

Pasture conditions are short and green, and there were some rainfall events over the last month. Worm egg counts have been conducted on ewes to assess their requirements for a pre-lambing drench, and on weaners to assess their requirements for drenching. Counts have varied from low to moderate, to high. The moderate to high counts, on culture, were due to barber’s pole. This is an important reminder that sheep may have been grazing infected pastures through autumn and this essential information should be used when selecting pre-lambing and winter drenches, as barber’s pole worm can be significantly resistant to white or mectin drenches. It also shows the importance of drench selection, rotational grazing and faecal worm egg count monitoring in managing worms.

Fluke has been detected on faecal tests of sheep on a few properties. Remember that this is a separate test that must be requested, and is advised if fluke levels are unknown or thought to possibly be a risk. Any positive result is significant. Winter is a very important time for fluke control in both cattle and sheep, and fluke can be controlled through drenching with a single active product such as triclabendazole, or combination products that also contain roundworm drenches.

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