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New South Wales worm update - March 2012

Steve Love, State Coordinator-Internal Parasites NSW DPI, Armidale (

April/May approaches. If you have liver fluke, this is the most important time of the year to give a fluke drench.

Make sure it is a highly effective one, i.e. a Triclabendazole-based one, or, in cattle, Nitromec®.

With a wet summer in many areas of eastern Australia, conditions would have been good for the liver fluke snail as well as liver fluke itself. While there may have been less cases of fluke disease (stock not forced to chase green pick into flukey areas), there is certainly more fluke, and some of the infective stage (Metacercariae) while make it through to spring, even if the cycle stops in winter because it becomes too cold for development of fluke eggs on pasture.

Regarding roundworms, it has been a bumper season for them as well. Keep up the worm egg count monitoring: Don't guess, WormTest.

If/when you do drench, check the efficacy of the drench by doing a DrenchCheck, consisting of a WormTest approx. 10 days after the drench (in the case of short-acting drenches), preferably matched by a WormTest on or just before the day the drench was given. (In cattle, do a DrenchCheck at day 14 instead of day 10).

A favourable summer and autumn (for grass and worms) means many infective larvae on pasture going into winter, some of which will make it through to spring, frosts notwithstanding.

If you lamb in spring, say September, then lambing paddock preparation should be underway soon (6 months before lambing in the more temperate (i.e. 'cold') sheep grazing areas of, say, the eastern third of NSW. To produce a low worm risk paddock for lambing ewes, the most important time to keep them sheep free is in autumn when it is still warm enough for eggs of some of the more important sheep worms to develop through to infective larvae on pasture. In colder areas and for some worms (notably Barber's Pole worm), it may be OK to graze sheep on lambing paddocks in the dead of winter (too cold for the eggs). Get good locally relevant advice.

Quite a few calves may be weaned about now. A weaning drench is required in most areas apart from low rainfall zones. To get more bang from your buck don't rely just on drenches to control worms, but prepare low-worm risk paddocks for young cattle. This might mean putting weaners into paddocks which haven't had other young cattle (calves to yearlings) on them in the preceding 4 months.

LHPA District reports

Lachlan LHPA

Eliz Braddon, Young (

Worm activity in the eastern area of the Lachlan LHPA have been on the rise particularly in stock less than about 18 months of age. Pre-lambing ewe counts have been very variable so the best advice for producers is “Don’t guess, worm test!!”

Your individual farm situation will be very different to those around you. Pasture contamination is another unknown factor. With the amount of ground cover present in pastures and the sustained moisture over the past 12 months, egg survivability has been very good so what would normally be considered a ‘clean’ paddock may not be as clean as expected.

By keeping a close eye on worm egg counts, disaster can be prevented before they rise too high. The good news is that with the large volume of good feed around, generally sheep are tolerating slightly higher counts without ill effects. So the classes to really keep an eye on are young stock and lambing ewes.

Barber’s Pole worm is also quite active at the moment and it can build up numbers very quickly.

Belinda Edmonstone, Forbes (

In the central area of the Lachlan LHPA average faecal egg counts for the month of February have ranged from 0-6520epg with individual counts ranging from 0-6600epg. I have been seeing losses soon after drenching in lambs as they have been put back onto dirty paddocks and have been reinfected very quickly. The wet season we have had highlights the need to plan clean paddocks for weaners and lambing ewes.

Katherine Marsh, Condoblin (

A number of WormTests have been conducted in the past month with the average count being 738epg (range 16-3000epg). The lower counts have tended to be in older sheep or those that have already been drenched early in summer. However, counts over 1000epg are still being seen in mobs that have already received a summer drench. Whilst some properties, particularly north of Condobolin, are seeing predominantly Barber’s Pole worm, Scour worms are still appearing in abundance in some tests. With the recent wet weather and flooding, worms will be very problematic for most producers. Monitoring for worms and careful consideration when choosing what drench to use cannot be stressed enough in the coming months.

North-West LHPA

Derek Lunau, Moree (

Floodwater has largely receded from the eastern part of the North West LHPA. Much of the western area is still inundated resulting in Haemonchosis due mainly to the necessity to set stock on higher areas and the difficulty in accessing the sheep for drenching.

We have been seeing sporadic cases of severe Haemonchosis. There were two cases last week, one where 50% of a small Dorper flock has died since New Year (6 dead) and the second case south of Carinda where only 15 lambs were lost from a few thousand, despite the 66,000epg in one dead lamb.

Over this season we are finding Closantel resistance in an increasing number of flocks. This is no longer a rare or sporadic occurrence in the district. As producers in our western areas especially rely on sustained action products, the loss of Closantel efficacy is a major blow.

There has been higher than usual use of faecal egg counts (WormTests) to monitor worm burdens and determine the most appropriate time to drench this season. This has allowed many producers to use “the right drench” at “the right time” with the results showing in thriving flocks.

Jim McDonald, Yass, (

The Yass District continues to be blessed by an excellent season with the prospect of any hot, dry weather to dampen down the worm larval contamination of paddocks all but gone. This places us in a similar position to last year with heavy loads of parasites in pastures readily available to re-infect recently treated sheep. Regular monitoring, along with exploring the options of either long acting injections or capsules, in young sheep to curb the parasite bombardment will need to be employed.

At present each property has a different make up of parasite species with Barber’s Pole becoming more prominent on more properties. Counts in the order of 2000-3000 are not uncommon.

WormTesting, incorporating larval diffs, is now essential to work out your worm control strategies for autumn/early winter to make the most of the current warm weather and good feed conditions.

Tablelands LHPA

Bill Johnson, Goulburn, (

Worms upped the ante with the arrival of a few days of sunshine. Barber’s Pole worms killed suddenly fifteen prime lambs on Lucerne. Lambs grazing Lucerne on a second property had worm egg counts in the tens of thousands six weeks out from an effective drench. Re-infection with Brown Stomach and thin-necked intestinal worms contributed to weight loss and exposure deaths in merino weaners a month off-shears and ewes treated four weeks ago with a long-acting injection still have worm egg counts up to three thousand. Amidst the carnage, though, some are sitting pretty, like a big mob of mixed age ewes drenched on New Year’s Day now with an average worm egg count of 20 eggs per gram. It again reinforces the message that all manner of worms are about, and not just in young sheep; but you won’t know unless you WormTest.

The most common excuse for not carrying out a drench resistance used to be “I haven’t had enough worms in my young sheep because of the drought”. This excuse has expired! Despite this, less than a handful of drench resistance tests have been completed. One resistance test this week showed only a triple combination drench passed muster; everything else used alone or in two-way combinations was unsatisfactory. (Zolvix® wasn’t tested.) And before getting the results, the owner was unaware of the severity of the problem, or the implications for his management. He now believes he’s found part of the reason for his poor lamb marking percentage last winter. Even if you can’t organise a full resistance test, what possible excuse is there for failing to test faecal samples 10-14 days after your most recent drench?

Remember those big metal boxes of colour pencils the rich kids had at school? Not even they had as many colours as the fleeces on some sheep after the rain. And aren’t the blowflies loving it! Blowfly horror stories abound. The best so far is 10% of merino weaners struck just four weeks after Cyromazine (the active ingredient in Vetrazin®), applied to six months wool with a fire fighting nozzle. Happily, our ten inches of rain has only marginally reduced the protection period when jetting has been done properly.

Riverina LHPA

Gabrielle Morrice, Narrandera (

In the southwest of the Riverina Authority, Dan Salmon says reports have been limited but worm burdens appear mixed.

Some very low counts, even in sheep not drenched for more than 12 months but some moderate counts.

There was one report which in retrospect is likely to have been Barber’s Pole worm.

A mob of sheep continue to die from liver fluke after several Triclabendazole drenches. They are grazing country unlikely to be suitable for the spread of fluke so resistance is the most likely explanation.

In the eastern area of the Riverina, Gabe Morrice says there have been few WormTests reported, however a number of clinical cases of scours associated with heavy worm burdens in weaned lambs and also goats have been investigated. A report of a suspected mixed infection including Barber’s Pole worm could not be investigated due to flood waters. Recent heavy rains and mild weather have the potential to lead to heavy contamination of sheep and lambs. In early lambing ewes it is now too late to drench, but later lambing ewes should be monitored and a pre-lamb drench given where worm burdens indicate it is necessary.

In the western part of the Authority there have been very few reports and no clinical evidence of heavy worm burdens. Col Peake recommends producers continue to be vigilant following the recent rain events.


Tony Morton, Wagga Wagga (

Highly variable counts and variable species identified have been the order of the day with recent results. As expected with the wet summer, Barber’s Pole worms are often present as the main species yet in other counts, its small Brown Stomach worms and Black Scour worms that dominate and not a single Barber’s Pole worm is to be found in the larval cultures.

With abundant feed, some adult sheep are looking good but have substantial counts. There have been plenty of surprised sheep owners who had low counts 6 weeks ago and now have significant counts due to high reinfection rates. Definitely a unique season, with the need to keep monitoring on a regular basis.

Central North LHPA

Judy Ellem, Coonabarabran (

WormTests from the Coonabarabran area in February and early March 2012 are showing high faecal egg counts with Barber’s Pole worm being the predominant problem. We have seen several cases of ill thrift and deaths in young sheep that can be attributed to significant Barber’s Pole worm burdens. There was however quite a range of average strongyle egg counts between properties, the average of all properties tested was 1320 and the range was 0 to 8300 strongyle epg.

12% of all properties that performed WormTests in the Coonabarabran area in February and March had a high Black Scour worm count. One property with a Black Scour worm problem had resistance to 3 different drench combinations. Another property had a Black Scour worm problem because the type of drench that was used is only effective against Barber’s Pole worm. This shows the importance of performing larval cultures whenever a high average strongyle faecal egg count is found as it cannot be assumed that Barber’s Pole worm is the cause.

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