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New South Wales worms, flies and lice update - March 2016

NSW WormBoss Worm Control Programs

NSW WormBoss Drench Decision Guides


Armidale: Rad Nielsen, Veterinary Health Research (

Rain events have been largely non-existent over the New England/North West region since January. Worm development would have come to a halt over the last two months, however larval intake has remained very high on properties that were unable to limit pasture contamination over the preceding months.

The VHR laboratory has seen some extreme worm egg counts in the past few weeks, many within 4-5 weeks of drenching. Haemonchus is typically the predominant worm species, however I have noted a higher than normal presence of trichs on some properties, involving both lambs and adult sheep (likely due to the relatively mild and wet December period). This highlights the importance of being aware of the composition of worm infections so that appropriate drenches can be used. Graziers also need to be mindful of the fact that levamisole, BZs, naphthalophos and combinations of these are not typically genuine broad spectrum drenches on New England properties.

The incidence and severity of liver fluke infections is likely to be high at this time due to a combination of the favourable developmental conditions over December/January and the fact that stock will have been forced into grazing low lying areas as pasture conditions have deteriorated. An autumn fluke treatment is advised for all properties where liver fluke is consistently an issue, for marginal properties/paddocks fluke testing is strongly advised in order to confirm the infectivity status of stock.


Bourke: Charlotte Cavanagh, VO (

Not enough rain around Bourke - just very humid weather!

There have been quite a few wormtest results coming through over the past month. While the counts were extremely varied, most were low. The strongyle type eggs present were a mix of mainly haemonchus and trichs.

Producers have been well organised in the lead up to shearing and submitted faeces for worm egg counting in case sheep needed to be drenched while still in the yards. There haven’t been any reports of scouring, weight loss or losses of sheep in general.

One producer checked every mob prior to shearing and sheep on the red country that had received some rain needed to be drenched.  The issue for this property is lack of clean or even rested paddocks for treated sheep. There was also a report from one property of elevated egg counts from sheep congregating around open bore drains and/or some swampy areas in paddocks.

After a string of more than 20 days of over 38°C in the Bourke district and no rain, larvae survival on pasture is poor particularly as there is little ground cover in some areas. The weather is set to cool down next week (low 30s) so fingers crossed for some rain - a change may also favour larval survival.

Out Wilcannia way, a wormtest on samples from a mob of badly scouring dorpers reported the highest count of 2280 epg - 100% trichs.  



Central West LLS

Coonabarabran: Cecily Moore, DV (

Recent weeks have been unusually hot and dry for this time of the year in the Coonabarabran region. There have been few worm tests submitted, but those that have been, have shown low egg counts. The exceptions to this are producers who have begun to grain feed their sheep due to the lack of pasture availability. These more crowded conditions have led to increased ingestion of worm larvae and a rapid build-up of worms. 

To try to combat this, producers should conduct a worm egg count, administer an effective drench if needed, and hold them in yards overnight before moving them into the paddock intended to be used to grain feed. This paddock needs to have been spelled for at least 3 months over summer to be considered low risk. 

With rain forecast for the coming weeks, but with still mild temperatures, stock should be monitored for signs of weakness, pale gums and scouring, as wetter conditions can lead to increased hatching of worm larvae and ingestion during grazing. 

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

With the recent dry, hot conditions internal parasites have not been much of an issue in the last month in the Forbes area. However, continual monitoring by performing regular WormTests is important particularly after the autumn break. Worm tests should also be performed on pre-lambing ewes to determine if a drench is required. These ewes should then be put on low risk pastures in preparation for lambing.


Riverina LLS

Wagga Wagga: Timothy Biffin, DV ( and Emily Stearman, DV (

Worm reports in the Wagga area have been moderate, as expected for this time of year. There have been a few lingering cases of barber’s pole, but nothing like the incidence seen prior to Christmas. Most producers have required a second summer drench, particularly in weaner stock (based on WECs). 

Regardless of whether sheep have been grazing on stubbles or other 'clean' pastures, producers should be performing egg counts in most of their stock at this time of the year. This information allows informed decisions in regards to the immediate requirements for worm management. Most farms will find significant production benefits moving into autumn if stock are "cleaned out" by the end of summer.


Northern Tablelands LLS

Inverell: Andrew Biddle, DV (

Hot dry weather on the western side of the Northern Tablelands has slowed (stopped) the barber’s pole worm reinfection cycle that hammered local sheep in spring and early summer.

While the worm egg count results have shown a lot of variation in the counts of the 10 samples that constitute a submission, the average worm egg count has been low.  There is still the occasional egg count over 1000 epg (eggs per gram) being reported.   

Glen Innes: Nigel Brown, DV (

It looks like the hot dry weather has certainly come to an end. 

The wet conditions in January provided an ideal environment for the survival of Haemonchus larvae on pasture, leading to a high larval challenge on many properties.  A number of high egg counts were seen. 

Hot dry conditions in February and early March will have reduced the number of larvae on pasture, but it's important to remember that these environmental conditions don't do anything to kill worms already living inside sheep. 

For this reason, it's still important to perform egg counts this month, as many sheep are likely to have picked up a high worm burden over summer.  If the forecast wet April eventuates, producers should keep an eye out for signs of scour worms


North West LLS

Nyngan: Erica Kennedy, DV (

The recent hot weather has eased clinical cases of barber's pole in the Nyngan and Warren districts with none reported for the last couple of months. However those producers who are submitting wormtests are seeing egg counts ranging from 40-1400 epg (with one outlier of 6200!) and thus, some have needed to administer an appropriate drench in the last few weeks. 

With an anticipated 'wet' April we will no doubt be seeing increased burdens and consequent increased production losses running into May. It is important for producers to take the opportunity whilst having sheep in the yards for other management procedures (shearing/crutching etc) to collect samples for wormtest analysis before drenching. Test kits are available from the LLS office in Nyngan and can be mailed to you. I also emphasise the importance of drench efficacy with many producers not knowing if their drenching has been effective (reducing egg numbers by >98).

Producers should be contacting their local veterinary advisor or district veterinarian if in the last 3 years they have not checked the effectiveness (efficacy) of the drenches they use.

Murray LLS

Deniliquin: Dan Salmon, DV ( and Linda Searle, DV (

In February, no clinical cases of internal parasites were reported in the western part of the area. There were 6 worm egg counts performed with an average of 105 eggs per gram (epg) strongyle type and 10 epg Nematodirus.  The results varied from 0-260 epg and 0-40 epg respectively.

Three results were typed and while two results showed the normal species variation for this area of 78-81% black scour and 19-22% brown stomach worm, the third result from the Jerilderie area showed a predominance of barber’s pole worm (83%) in weaned lambs treated with an abamectin/praziquantel drench in November.

Barber’s pole has not been a large issue in the western part of the area this year due to the lack of summer rain. However it is worth keeping in mind that barber’s pole may be present if sheep are showing anaemia and bottle jaw, rather than scouring.

In the eastern part of the area a number of properties have had high levels of barber’s pole which coincided with up to 100mm of rain in late January and early February.  This indicated that barber’s pole is relatively prevalent in the area, and producers need to be vigilant using monitor worm egg counts through the summer especially when summer rain occurs. Other worm numbers have been typical for this time of the year.


South East LLS

Goulburn: Bill Johnson, DV (

Extended hot, dry conditions have slowed our barber's pole problem, but only for the time being. This weather prevents hatching of worm eggs, and kills worm larvae already on pasture. However, recent worm egg counts in some mobs are well into the thousands of eggs per gram, all barber's pole. And these worms will still be pumping out worm eggs when autumn arrives. I'm frequently told by producers that they've never had a problem with barber's pole before this year, so don't become too complacent. It will be warm enough for barber's pole worm eggs to hatch for another month, if we get rain. Any larvae that develop will be able to survive right through winter. So it is important to do a worm egg count and worm type now, to know what you're dealing with.

A sizeable burden of healthy adult barber's pole was found during a routine autopsy on a merino ram this month, a week after drenching with a popular "triple" drench (abamectin+BZ+levamisole). Worm egg counts on other rams in the mob ranged between 800 and 8800 eggs per gram. It was a reminder to do a worm egg count 10-14 days after drenching, to check that the drench has worked. A nation-wide review in 2014 showed drench resistance to the "triple combination drenches" was present in about one in four flocks. Resistance has been found in brown stomach worms and barber's pole worms.

On another property, egg counts the owner described as "horrendous" were found in adult sheep drenched a couple of weeks previously with abamectin on its own. Barber's pole are likely to be resistant to abamectin used alone in the majority of our sheep flocks. Abamectin should only be used as part of a combination drench.

Another autopsy, this time on a 40kg crossbred lamb, showed immature liver fluke. The owner hadn't seen liver fluke on this property for some years. Liver fluke in cattle has been on the increase in the district, and we've been expecting levels in sheep to follow suit. This lamb had been on typical "flukey" country (paddocks with a spring, swamp or creek) for only a short time, and its liver was peppered with holes and the belly was full of protein-rich fluid. It is possible that all the closantel used around here to control barber's pole worm over the past few years may have suppressed the expected build-up of liver fluke in sheep. It takes about three months following fluke pick-up before eggs appear in faeces, so a fluke test on faeces during this time will miss the infection. A blood test is better. If you have had liver fluke on the property in the past, but haven't needed to fluke drench for several years, it would be worth testing sheep running in suspect paddocks.


Yass: Fiona Kelk, DV (

The level of worm egg count testing conducted across the Yass district has reduced during the last 4 weeks, those carrying out typing (larval cultures) have found barber's pole dominating the counts. 

The warm/hot weather has eased worm burdens, except on 2 properties where grazing along creek/river flats has occurred. 

Producers are encouraged to use WEC to monitor parasitic burdens levels in their flocks.

Wishing you all a safe and enjoyable Easter break.

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