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New South Wales worm update - April 2013

Rad Nielsen, Veterinary Health Research, Armidale (rnielsen@vhr.com.au) :

Worm challenge remains high in the New England region despite the recent lack of rain. Paddocks in which sheep were grazing during the major rainfall events around Christmas and late February are proving to be particularly “hot” in respect to Haemonchus. We are finding that many producers are having to drench monthly in order to avoid worm production loss. This is often exacerbated by the use of ineffective drenches.

It can no longer be assumed that levamisole and moxidectin will be effective against Haemonchus. VHR data generated from extensive drench resistance testing over the 2011/12 period (New England region) confirmed levamisole resistance in 57% of the properties tested. Moxidectin resistance was present in 74% of sites. Given these alarming figures, I urge all sheep producers to conduct drench resistance tests on their property(s). At a minimum, post drench checks should be performed.

Autumn is an important time for liver fluke monitoring and treatment. Producers who have encountered this parasite on their properties (or suspect that they do) are advised to assess their current infection status via faecal egg counts (or blood testing). A significant percentage of New England properties are testing positive for liver fluke (both sheep and cattle) at this time. 

LHPA DISTRICT REPORTS

Lachlan LHPA

Belinda Edmonstone and Nik Cronin, Forbes (Belinda.edmonstone@lhpa.org.au)  (nik.cronin@lhpa.org.au)

In the central area of the Lachlan LHPA average faecal egg counts for the month of March have ranged from 0-328 with individual counts ranging from 0 – 840. These are the lowest counts I have seen in a number of years. This can be attributed to the dry seasonal conditions and good strategic drenching by the producers as many had given a first summer drench. Continue to monitor pregnant ewes by performing a worm test 4-6 weeks pre-lambing.

Kasia Hunter, Condobolin (kasia.hunter@lhpa.org.au)

In the western area of the Lachlan LHPA only three WormTests were conducted during the past month on two separate properties. Two tests from one property were DrenchChecks, 10 to 14 days post-treatment. There was no indication of drench inefficacy, however pre-treatment WormTest results were not obtained; therefore limited information can be extrapolated from these tests as pre-treatment worm burdens were not known. The third WormTest was in a mixed mob of approximately 10 month old 1st-Cross sheep, and demonstrated an average faecal egg count of 0 (all individual counts were 0). These sheep had been drenched with Q-Drench 2 months prior to the WormTest being conducted. No stock losses or evidence of parasite-related problems have been reported in the last month. The dry seasonal conditions have certainly played a role in reducing parasite burdens. Nevertheless, a pre-autumn lambing WormTest (and drench, if necessary) is strongly recommended for pregnant ewes.

Eliz Braddon, Young (eliz.braddon@lhpa.org.au)

In the eastern end of the Lachlan LHPA, 35 worm tests were done this month.  The majority of these are in preparation for upcoming lambing.  In general the ewe mobs have been pretty steady with most mobs not requiring any drench at this time.  However, the variability in just these few tests was from an average egg count of 20epg to as high as 1340 epg!  So if you happen to have the mob with the 1340 epg and don’t test them prior to lambing, you may find yourself in a bit of trouble halfway through lambing when the worm burdens really can explode.  The only way to know what is likely to be happening on your farm, is to test some of your own mobs of sheep.  Of the 10 larval differentials run, a good representation of our problem worms was found – Trichostrongylus (Black Scour worm), Ostertagia (Small Brown Stomach worm) and Haemonchus (Barber’s Pole worm) – almost always in mixed populations. 

Cattle tests have been very low – well below 100 epg but we have had at least one farm with significant liver fluke activity post-flooding events last year.  So if your cattle are looking a bit listless, or have bottle jaw AND you have creek areas with the potential to harbour the fluke snails, then either a faecal test or a blood test can help diagnose the problem.  April is one of “the months” to clean up fluke so if you are thinking fluke is a problem, now is the time to act.

Bob Templeton, LHPA DV, Braidwood (Bob.Templeton@lhpa.org.au)

Not many WormTests have been done around Braidwood/Bungendore.  We still see barbers pole hanging on  and black scour has not taken off.  Resistance by barbers pole worm to ivomectin is increasing.  The first frosts should be here very son and so the liver fluke pick up will cease.  A good liver fluke drench is recommended during May.

Central West LHPA

Alan Taylor, LHPA DV, Dubbo (alan.taylor@lhpa.org.au)

There have been numerous worm tests done across our region, with most coming back with zero to 200 epg. However Barbers Pole Worm is still a problem on some farms, with one mob of Xbred ewes averaging 800 epg., and another property showing 1150 epg- nearly all BPW.

Owners have been advised to wormtest two weeks before lambing to check on the worm burden and allow time to drench if required.

Tablelands LHPA

Bill Johnson, Goulburn, (bill.johnson@lhpa.org.au)

Barber’s pole worms have again taken centre stage. They were a reasonable proportion of worm egg counts through the summer in many flocks, but exploded to cause deaths following late summer rainfall. Crossbred lambs and Dorpers were most commonly involved. Barber’s pole used to be an infrequent problem in southern tablelands sheep, but has been with us for three years on the trot. Of concern, many more flocks have this year discovered that their strain of barber’s pole worms is resistant to one or more of the commonly used drenches, including moxidectin (both oral and injection), abamectin, closantel and levamisole. A drench check test is highly recommended, 10-14 days after drenching.

It is now too cold for barber’s pole eggs to develop into new larvae, but larvae already on heavily contaminated paddocks will survive frost, and will continue to re-infect sheep throughout winter.

Tick the ‘worm type’ box when next you do a worm egg count to assess the level of barber’s pole in your sheep.

Recent sampling shows an increasing proportion of flocks with positive liver fluke counts. Remembering that it takes three months before fluke develop to lay eggs, now is a good time to faecal test mobs grazing creek paddocks during summer. Or ask your vet about collecting blood samples from your sheep and cattle for a more reliable liver fluke test.

Lambing is about to start in many flocks, and ewe nutrition will largely determine their fate. Feed quality and quantity has declined markedly in recent weeks, and ewe body condition will follow, without supplementation. While there may be fewer worms on lambing paddocks than in the past two years thanks to a dry summer, ewe resilience will be greatly influenced by available feed.

Tablelands LHPA

Jim McDonald, Yass (jim.mcdonald@lhpa.org.au)

The Yass District, like most of the state, is experiencing a dry autumn.  Worms and flies have been a minor concern over the last 3 months.

Worm egg counts have been carried out by a small percentage of producers with ranges from 40 – 280 epg the norm.

There are still a handful of properties where Barbers Pole is the dominant worm but these are in the minority.

The last 3 years have seen a huge jump in use of long acting products, both injection and capsules, but I would think at this stage demand for these products pre-lambing will be well down on last year.

The quality of pasture is starting to decline which will put weaners under stress and potentially increase worm problems this winter.  Continued monitoring through May and June will be crucial if a setback is to be avoided in these young sheep.

Hume LHPA

Tony Morton, Wagga Wagga ( tony.morton@lhpa.org.au)

Despite the hot dry summer and generally low counts there have been  several  instances where drenches in November were not followed up  with  monitoring or a second summer drench  and counts are now excessive. e.g. 1st cross ewes 496 e.p.g, merino ewes 500 e.p.g. This means that  there has been  autumn  pasture contamination  setting the sheep  up  for a high  intake of larvae in winter which  will mean  additional  treatments .

The core concept of the two  summer drenches in this area is to  hit the worms twice during summer when reinfection is generally lowest and thus minimise the  late summer and autumn contamination  which  in turn  leads to  the larval  peak  on pasture in July.

If you are contemplating missing either summer drench, a worm test of all mobs is essential

Riverina LHPA

Gabe Morrice, Narrandera: (Gabe.Morrice@lhpa.org.au);

Colin Peake, Hay; (Colin.Peake@lhpa.org.au);

In the Western Riverina it has been very dry, approaching drought conditions, as no good rain since February/March 2012.

Very few wormtests being done. The 2 for the last month have been very low with counts in one with an average of 40, range from 0 – 80 epg & an average of 160, with a range of 40-360 in the other. Due to the hot dry summer there are few worms, producers are destocking and starting to feed. Pregnancy toxaemia is an issue due to lack of feed & Autumn lambing starting. We are seeing the odd case of grain poisoning as well.

Similar problems in the South Western Riverina.

In the Eastern Riverina, there has been more rain, so seeing more evidence of the odd worm problem.

Producers would be prudent to do pre lambing wormtests when they vaccinate their ewes to see if drenching is required.

North West LHPA

Fiona Fishpool, LHPA, Moree (fiona.fishpool@lhpa.org.au)

Only a few worm tests have been conducted in the Narrabri and Walgett areas. Those received have been overwhelmingly dominated by Haemonchus contortus with means ranging from <100 epg up to 3500 epg. Haemonchus contortus has also been a problem throughout the eastern side of the North West district with some deaths, mainly in weaners and lambs but also in mature sheep. The higher counts are not surprising in areas that received more than 100 mm of rain in Feb/March.  Conducting an autumn Wormtest is strongly advised for producers that received reasonable rainfall.  A strategic drench now may pay dividends come spring.