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New South Wales worm update - October 2012

Rad Nielsen, Veterinary Health Research, Armidale, (

Worm monitoring results at VHR over the last month have been varied. Some extreme counts have been seen in ewes post lambing (in excess of 3,000 epg mean), whilst other producers appear to have good control of worms. The difference largely comes down to management and paddock planning. Paddocks that were “wormy” back in Autumn are still likely to be a high larval challenge environment, whilst ewes lambing in prepared “low worm” paddocks have low-moderate infections at lamb marking.

Early spring has been dry across most of the New England. Haemonchus development will have been restricted for this reason; however graziers will still need to be vigilant. Regular worm egg counts (every 3-4 weeks), is the best way to monitor the worm status of sheep.


Lachlan LHPA

Eliz Braddon, Young, (

In the eastern division of the Lachlan LHPA, producers have been doing increased monitoring prior to ewes and lambs being yarded for management (e.g. marking, weaning). The overall average across all age groups was 460 epg with a range of 40-1480 epg, so in general worm egg counts are on the rise with the warmer weather. Most cultures revealed a predominant scour worm population (Trichostrongylus – Black Scour worm; Ostertagia – Small Brown Stomach worm) with a few signs of Haemonchus (Barber’s Pole) also showing up. We know that our area had some significant Barber’s Pole worm burdens last summer and autumn so producers need to be aware of this. It would be wise to do a larval culture in the early spring/summer worm egg counts in order to know what worms are actually active. This will ensure that producers have all the right information when choosing a drench for this year’s rotation.

The Condobolin office should be back up next month with our new DV, Kasia Hunter, replacing previous District Vet, Katharine Marsh.

Belinda Edmonstone, Forbes, (;
Nic Cronin, (

In the central area of the Lachlan LHPA, average faecal egg counts for the month of September have ranged from 0-1100, with individual counts ranging from 0-4000. Worm activity has slow down as a result of the dry weather, although some producers are still seeing losses mainly from Black Scour worm. As the weather warms up and with recent rain at the end of September, Barbers Pole worm activity will start increasing on paddocks as these worms produce large numbers of eggs. Depending on rain, this worm could cause issues again this summer so producers need to be vigilant in their monitoring of worm numbers and in the preparation of “low risk” pastures for susceptible sheep.


Tony Morton, Wagga Wagga, (

As with past months, counts were very variable around Wagga. While Trich’s (Black Scour worms) and Ostertagia (Small Brown Stomach worms) were often the culprits (as expected in winter/early spring), there were also cases where infective Haemonchus (Barber’s Pole) larvae from last autumn had persisted, infected sheep and were then contributing to counts. A very dry September and early October are doing pastures and crops no good but should be helping to drive down larval contamination. The most recent egg counts tend to reflect this.

New England LHPA

Steve Eastwood, Armidale, (

At a pasture level, the build-up of Haemonchus on pastures has ceased with the onset of frost; however there is still the risk of sheep picking up Haemonchus larvae already hatched. We are currently advising the continued spelling of lambing paddocks since the start of April. They should only be grazed, if feed is an issue, with cattle. 

Sheep should have received an effective broad spectrum drench to reduce the build-up of Scour worms over winter.

A good plane of nutrition is vital for stock over the winter months to aid in the innate resistance and resilience of sheep to worm burdens.

Tablelands LHPA

Bill Johnson, Goulburn, (

Worm egg counts continue to show huge variations not just across the district but between mobs on the same property. Barber’s Pole worms account for some of that variation. If present, the egg output from just a few of these worms is equivalent to a whole lot of Scour worms. It is useful to ask for a worm culture to know what worms are present.

The other message from this variation in worm egg counts between mobs is that the level of paddock contamination can be very high. There is the temptation to leave lambs on the ewes just a bit longer when there is this much green feed around, but the effect of worms will soon erode any perceived benefit. Weaning, drenching and a move to a low worm pasture should not be delayed this year.

Don’t forget to check for liver fluke, particularly if you have a history of previous fluke problems pre-drought. Some of the sheep dying with fluke have had huge burdens.

Jim McDonald, LHPA DV, Yass, (

Worm burdens continue to trouble Yass District producers, with counts in young sheep ranging from 200- 6200 epg. Losses were occurring in weaners at the higher end of the counts, with four animals sampled individually showing severe scours ranging from 3760- 7680 epg. On a local property, losses had begun to occur five weeks after drenching, with counts relatively low at 280 and 560. A huge amount of damage had occurred from immature parasites, with total worm counts of Osters 34600 (1000 were mature) when a heavy burden is >5000, and Trichs 41800 when heavy burden is >5000.

In adult ewes, counts of 500 epg at lamb marking are common.

Pasture contamination in most paddocks is extremely high and will remain so until the end of November at the earliest. Monitoring regularly and treating weaners and ewes with effective drench at weaning will be essential to keep the worms in check.

South East LHPA

Bob Templeton, Braidwood, (

Worm egg counts are gradually climbing up across the Braidwood area.  Black Scour worm is still the main problem, but the eastern fall may see a rise in Barber’s Pole worm following the rain and snow in mid-October. A WormTest is advisable before the first summer drench next month in the eastern fall.

Riverina LHPA

Gabe Morrice, Narrandera, (

There has not been a lot of activity in the southern part. There have been very few tests or reports of clinical problems. One mob of Dorper ewes were scouring and losing condition with egg counts of 1400 epg. Other Wormtests were in the 200-500 epg range.

Colin Peake, Hay, (

There has only been one Wormtest conducted in this area in the past month. It was in undrenched four-month-old merino lambs and they had an average egg count of 1552 epg and a maximum count of 3120 epg (worm type not yet available).

With feed “haying off” across most of this area, the first summer drench could be given any time from now on.

Dan Salmon, Riverina, (

No WormTests have come through this month for the Western Riverina LHPA and there have been no reports of clinical disease. It has been very dry since March and isn’t looking good for summer. In saying that, most sheep in the district look very well. The Store sale in Hay last month of 55,000 sheep, the largest sale for years, saw sheep in very good condition and the best quality yarding I have seen here to date.

Central West LHPA

Evelyn Walker, LHPA DV, Dubbo, (

In our area, a few well-meaning farmers drench at lamb marking. This practice is generally discouraged since lambs pick up so few worms at this age. Young lambs spend most of their time on their mother’s milk rather than actively grazing. Drenching at lamb marking is recommended only in extenuating circumstances, such: lambing in highly contaminated paddocks; lambs at foot dying of worms; ewes drying off prematurely and lambs being forced to graze contaminated paddocks earlier than usual.

If you are concerned your young lambs have worms, do a worm test on your lamb mob. And if you do find yourself in one of the above extenuating circumstances, be aware of some of the dangers of drenching very young lambs. One farmer in our area learned the hard way. Lambs were vaccinated, tailed, castrated and drenched in the cradle with an abamectin combination. On property visit, seven had died soon after marking and 50% of the lambs displayed various symptoms of drench toxicity. Symptoms ranged from rapid breathing, stumbling, head tremors, full body tremors, inability to stand, dilated pupils, stupor, and profound depression. Further enquiry revealed that lambs were dosed at 25kg body weight.

So just a friendly reminder of drench do’s:

  • Do take the time to read the label.
  • Do check the label for any contraindications.
  • Do take care with dose rate when drenching young lambs.
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