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New South Wales worm update - June 2012

Steve Love, State Coordinator – Internal Parasites, I&D NSW Primary Industries, Armidale:

Remember worms don't go away over winter.

It might be cold enough to interrupt the life cycle, particularly in the case of cold sensitive worm eggs like those of Barber’s Pole worm and liver fluke, but the infective larvae on pasture from autumn are somewhat hardier.

Keep up the worm egg count monitoring!

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

Recent faecal egg count results from the New England region are a “mixed bag”.

Some high worm egg count results (including Black Scour worm dominant infections in young sheep) have been seen, along with a number of situations where the worms have been kept well in control. The threat of Barber’s Pole worm outbreaks has largely subsided over the New England region for now. The cold conditions prevent further Haemonchus development, however producers need to be aware that existing larval pasture contamination will to a large degree successfully over-winter.

It is important to be monitoring the worm egg count levels of all sheep at this time. Weaners may be at risk of Black Scour worm infections, particularly if nutritionally compromised. Meanwhile, the drenching interval for adult sheep may be extended throughout the winter months given favourable worm egg count results. Sheep producers really need to be striving to minimise the use of anthelmintics in light of the deteriorating drench resistance situation.

Recent drench resistance testing conducted over the New England region has highlighted the alarming extent of drench resistance. It is now not at all uncommon for properties to have only two genuinely effective Haemonchus drenches – those being Zolvix (Monepantel) and Colleague (Pyraclofos + BZ). Levamisole and Moxidectin resistance is now a typical finding in some areas and Naphthalophos is often found to be deficient against immature Haemonchus at the very least. These findings should serve as a warning to all sheep producers who deal with Haemonchus. Steps should be taken to minimise drench use by incorporating grazing management into their farm program and drenching on an “as need” basis, along with selecting sires with negative EBV for worm resistance.

LHPA DISTRICT REPORTS

Lachlan LHPA

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

In the eastern section of the Lachlan LHPA, average faecal egg counts have ranged from 12- 2480epg with pre-lambing ewes being the predominant class of stock being tested. On average these ewe mobs have required drenching at around 400epg. There have also been some investigations into ewe losses in mobs that have almost finished lambing and Haemonchus (Barber’s Pole worm) has been the culprit. In these instances, drenching was done pre-lambing in Mar/April and the ewes are just finishing now. This has allowed the ewes to become reinfested from pasture as Barber’s Pole was still fairly active in April and May. Now that temperatures are consistently running below 10 degrees on average, this should start to drop off. However the problem of highly contaminated pastures continues. Grazing management either by cropping, sowing pastures or grazing with cattle to try to clean up these pastures is recommended if at all possible in your situation.

Belinda Edmonstone, Forbes (belinda.edmonstone@lhpa.org.au):

In the central area of the Lachlan LHPA average faecal egg counts for the month of May have ranged from 0-4840epg with individual counts ranging from 0-20800epg. Barber’s Pole worm continues to plague us. Producers are losing lambs born onto paddocks that are not ‘low risk’. This really highlights the need to prepare ‘low risk’ paddocks for lambing and weaning.

Katherine Marsh, Condoblin (katharine.marsh@lhpa.org.au):

There has been little worm testing conducted in the past month, but there still have been some enquiries about worms, although focus seems to have turned to Scour worms rather than Barber’s Pole worm so producers are reminded to still be vigilant for worm issues. Also producers are reminded to monitor pre-lambing ewes for worms as ewes may see a relaxation in their immunity to worms at this time.

Tablelands LHPA

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

There is a huge variation in worm egg counts, not only between properties, but between similar mobs on the same property. This means it is risky to base your decisions about worm control for ewes pre-lambing on the results of a worm egg count on just one mob.

Where worms are present in significant numbers, there’s been a late resurgence in Barber’s Pole worm on many properties, while Black Scour worm are predominant on others.

No-one is losing sheep from worms at present, but ‘all the ducks are lining up’ for problems to occur during late winter lambing, similar to last year. The combination of bulky poor quality pastures and heavy worm contamination over autumn proved lethal in 2011, and will happen again in 2012. If you had problems last year, or your lambing paddocks are likely to be contaminated (such as where young sheep were grazed in autumn), consider using long-acting pre-lambing drench products and supplementary feeding for lambing ewes.

Liver fluke are on the rise, corresponding with replenishment of drought-affected springs, creeks and swamps. Check for fluke with a mid-winter dung test, targeting those mobs that grazed such low-lying country during summer and autumn. (Remember also that it takes about three months from when a sheep eats an immature fluke until eggs appear in the dung.)

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

The Yass District is experiencing an early and hard winter with below average temperatures for May and I would think early June. Grass growth has slowed dramatically and stock generally are maintaining condition but few are growing.

The occasional property still experiencing Barber’s Pole worm, with counts from one holding in weaner Dorpers ranging from 40-4680, averaging 1740epg with 67% BPW.

Weaners elsewhere counts range from 120-1160, averaging 500-600epg with a typical count 46% Trichs, 16% Osters, 6% BPW and 32% Oesophagostomum.

To keep on top of the worms, weaners will need to be worm tested every 4 weeks.

Pregnant ewes ranging from 0-320 with averages about 100epg in well managed flocks.
Conditions continue to greatly favour the parasite well into spring so there won’t be an opportunity to relax for some time yet.

Riverina LHPA

Colin Peake, Hay (Colin.Peake@lhpa.org.au); Gabrielle Morrice, Narrandera (Gabe.Morrice@lhpa.org.au); Dan Salmon, Deniliquin (Dan.Salmon@lhpa.org.au):

Egg counts seen for sheep in the eastern side of the Riverina LHPA over the past month have been low. Producers are reminded to monitor their sheep if they believe scouring is due to worm burdens.

In the Western and Southern Riverina, there have been very few egg counts, which have all been low. There has been no evidence of clinical disease. The last 2 months have been very dry, less than 10mm per month - typical western Riverina. WormTest if you see any scouring.

Hume LHPA

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

The situation remains extremely variable at Wagga with everything from negligible counts to high counts and clinical disease. Barber’s Pole worm and Black Scour worm have been the main species but small brown stomach worms have also been seen. The colder conditions have reduced reinfection with Barber’s Pole worm; we are moving into the period of the year where Black Scour and small brown stomach numbers on pasture are likely to peak and on many properties the peak will be very high from late summer and autumn contamination.

South-East LHPA

Bob Templeton, Braidwood (bob.templeton@lhpa.org.au):

Around the Braidwood/Monaro it has been cold and wet. The Barber’s Pole worms are refusing to lie down and die. At the same time generally the Black Scour worms are not emerging as anticipated with the weather conditions. However, the heat caused by Barber’s Pole worms is now settling down and life is somewhat easier. That being said, there are flocks that have come through the summer with no Barber’s Pole problems but significant loads of Black Scour worms.

North-West LHPA

Plains areas Walgett, Narrabri and Moree – DV Libby Read and Shaun Slattery

The occasional clinical cases of Barber’s Pole infestation are still being reported.

WECs continue to be variable with a complete range from no action, to urgent treatment required. However, there is still a reasonable portion with substantial subclinical burdens.

As these subclinical burdens will quickly contaminate pastures in spring with any rainfall, we are currently recommending all flocks perform WECs.

With the very dry conditions since the floods of early February till the start of winter, we expect that on pasture larval contamination in spring, from over wintered larvae deposited in autumn, should be minimal.

Western northern slopes Warialda, Bingara – DV Ted Irwin

Similar picture to the plains with no clinical cases of Barber’s Pole worm infestation reported or investigated in the last month. An absence of WEC monitoring by producers makes further assessments difficult.

Central West LHPA

Evelyn Walker, LHPA DV, Dubbo (evelyn.walker@lhpa.org.au):

Phone calls and property visits related to worms for the month of June have settled down. However, worms still have a very active presence in the Central West. Worm tests conducted in the Central West range anywhere from low, medium (mostly) and a few with heavy worm burdens. The highest reported average epg for the Central West was 17,740!

The Barber’s Pole worm is still rearing its ugly head on a few places. One property in Wellington in fact had 99% Barber’s Pole worm and 1% Black Scour worm.

In contrast, another property in Wellington only had 8% Barber’s Pole worm and 73% Black Scour worm.

The Black Scour worm appears to be gaining some momentum this month. This emphasises the importance that no two farms are alike and the value of doing worm tests.

If you are lambing soon, it is paramount that you check your ewes three to four weeks prior to lambing with a worm test and drench if required.

You can time your pre-lambing drench with your pre-lambing vaccination. These practices not only ensure the health of your pregnant ewes, but also the health of their newborn lambs.


DownloadDownload the June edition of NSW worm update in PDF format (104 KB)