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New South Wales worm update - February 2013

Stephen Love , Veterinarian, State Coordinator-Internal Parasites, NSW Department of Primary Industries, Armidale (stephen.love@dpi.nsw.gov.au):
Over the last month, the eastern quarter of NSW, especially the north-eastern corner, has got above average rain, 150-200% of average in places. The rest of the state has tended to be below average rain wise. But the 2-3 months before that saw most of the state getting below average rain.

Worm eggs, not least Haemonchus (barber's pole worm), prefers smaller falls frequently (e.g. 15 mm plus per week) rather than big falls once every blue moon. Much of the rain of late - for those areas getting it - has come as big falls with storms. However, with follow up rain, worms could become an issue more generally, despite the slow start to the season worm-wise.

Even though worm egg counts around the state have generally been low to moderate, there have been some flocks in many districts returning reasonably high egg counts - for example, WormTest averages up around a few thousand eggs per gram (usually but not always mostly Haemonchus), with some individual animals with counts up to 17,000.

So, while WECs might be generally low in your district, or on the property next door, you still might get caught with your pants down (so to speak).

As to liver fluke, there has been a decent smattering of positive tests for liver fluke eggs in the traditionally flukey districts. Perhaps sheep are moving into 'flukey 'areas on some farms chasing green pick if conditions have been dry.

In short - yes you've heard it before - don't guess - WormTest.   You might avert a disaster, or you might save yourself some unnecessary drenching, and selection for drench resistance.  Of course, if you do need to drench, do a DrenchCheck 10-14 days after the drench. You've heard this before too - the most expensive drench is the one that doesn't work.

More information    
WormTest:  http://www.wormboss.com.au/tests-tools/tests/checking-a-mob-of-sheep-for-worms.php      
DrenchCheckDay10:  http://www.wormboss.com.au/tests-tools/tests/checking-for-drench-resistance.php

LHPA DISTRICT REPORTS

Lachlan LHPA

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

In the Forbes area of the Lachlan LHPA there have only been 3 worm tests performed by 2 producers reflecting the dry conditions that we have had.  The average count ranged from 20-300 epg, and individual counts ranged from 0-360 epg.  A barber’s pole population was still evident, as well as the scour worms.  It will pay for autumn lambing flocks to remember to conduct a pre-lambing worm test to see if a drench is required.  If we do have some rain over the next few months into the lambing period, barber’s pole could cause a real problem. 

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

In the western area of the Lachlan LHPA only a small number of Wormtests (4) were conducted over the past month. The results were highly variable with average faecal egg counts ranging from 8 – 448epg, individual counts ranged from 0 – 2680 epg. These results highlight the level of variability in parasite burdens between properties and between different mobs of sheep. It is therefore crucial that farmers are aware of their individual situations by conducting regular Wormtests. The predominant species identified in all of the Wormtests conducted was Haemonchus (Barber’s Pole Worm). On one property this parasite was present at 100% based on larval differentiation results! This goes to show that despite the hot and dry conditions, Haemonchus can persist and reach levels where the worms will have a negative impact on sheep health and productivity. Ostertagia (Small Brown Stomach Worm) and Trichostrongylus (Black Scour Worm) were also present in some results but at relatively low levels. It would be advisable for producers to consider performing a Wormtest during February to determine whether a second summer drench is required.

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

In the eastern area of the Lachlan LHPA, 15 worm tests were undertaken in January.  Of these 10/15 were below the 200epg where normally a drench would be considered to be required.  Most of the testing has been in autumn lambing ewes prior to their pre-lambing treatments.  Of the 4 differentials done, all contained Haemonchus (Barber’s Pole), Trichostrongylus (Black Scour) and Teladorsagia (Small Brown Stomach) in reasonable proportions.  This is an interesting finding, considering how dry it has been with only a few lighter showers for late December and all of January in this area.  There was also considerable variability in the worm test results ranging from 16-1380 epg.  This little burst of Haemonchus after just a small amount of rain is a timely reminder to keep an eye on things, particularly if we continue having warm weather (eg. >20˚C) and also get a bit of rain to increase the humidity levels.  This is the time of year and conditions that Haemonchus are particularly fond of so producers need to stay on the alert.

Central West LHPA

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

Worms are still lurking in the Central West region with average egg counts ranging from 0 to 853. The predominant worm type is mainly Barber’s pole worm and a few properties are showing mixed infections of Barber’s pole worm and Brown stomach worm. Production losses attributed to worms have not been reported this month. High worm burdens however have been seen in sheep that were missed at summer drenching or in recently purchased/introduced sheep from other areas. The dry conditions experienced in our area are keeping worm activity at minimal levels compared to previous years.

Tablelands LHPA

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

Grown sheep have enjoyed the drier conditions, and generally look pretty fit across this patch of the tablelands. Several producers have done worm egg counts prior to giving a second summer drench, and the results show great variability and no obvious pattern. In the majority of mobs, these worm egg counts indicate the mob needs that drench. Some mobs again have a pretty high proportion of barber’s pole worms. There’s not enough moisture (rainfall, dew, green pasture and wet gullies) for this to be an immediate problem on many properties, while other places have caught some decent storms and follow-up showers, and need to be on ‘barber’s pole alert’.

As discussed last month, lambs are struggling to find sufficient quality pasture. Low pasture protein and poor digestibility cause many weaners to lose weight if not supplemented. Weaners losing weight are prone to die, often associated with reduced immunity to worms. However, the juggling act that is feeding weaners continues. On the one hand, there have been some severe outbreaks of scouring caused by Nematodirus (thin-necked intestinal worm) following localised rainfall; while on the other hand, the disappointing loss of big weaners from grain poisoning on self-feeders adds to the frustration! One recent case highlights the Nematodirus story: a fair percentage of the lambs were scouring on a green pick a few weeks after rain. The worm egg count was zero, but an autopsy showed gut damage caused by a moderate burden of immature Nematodirus.

Charlotte Cavanagh,  Veterinary Officer, NSW Department of Primary Industries, Bourke (charlotte.cavanagh@dpi.nsw.gov.au )

We only had one worm test submitted over January/first half Feb and it was 0epg!  This was in a mob of Dorpers that are losing weight. They were last drenched in August last year. (All according to the submission). Just between you and me these sheep are on red/mulga country and it is VERY dry out here. I would say they are losing weight due to lack of feed - certainly not because of a worm burden.

Hume LHPA

Amy Shergold,  Wagga Wagga,  (Amy.Shergold@lhpa.org.au)

The continuing hot dry conditions have resulted in a relative lull of worm activity around Wagga Wagga. We know of seven producers that have undertaken worm tests in the past month. In total, 17 mobs were sampled representing weaners, hoggets, dry and Autumn-lambing ewes. Only four of these tests had average counts of >200 epg, including one farm that had not given a first or second summer drench. Average counts ranged from 20 – 288 epg. Additionally, two mobs had counts of all 0s following effective drenching a fortnight beforehand. Individual counts were more variable ranging from 0 – 1120 epg. Only one culture was performed revealing a mix of Trichostrongylus (Black Scour) and Teladorsagia (Small Brown Stomach) worms. Although no Haemonchus (Barber’s Pole) activity was demonstrated on worm tests, a recent autopsy confirmed infestation in a weaner lamb that died of heat stress. The lamb had been running in a paddock with a small creek that had dried-up a couple of weeks earlier. This may have provided the warm moist climate that Haemonchus likes. Despite many low counts, all three worm species are around and February is a good time to monitor and assess the need for a second summer drench. It is also advisable to worm test Autumn-lambing ewes as they may need a pre-lambing drench.