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New South Wales worms, flies and lice update - August 2016

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

Worm egg count results from the New England region over the last month continue to remain in the low to moderate range in the majority of cases, however some properties have recorded high mean counts (in excess of 1000 epg). Haemonchus are typically the predominant species in culture results, however Trichostrongylus (black scour worm) have been notable in a number of submissions (typically weaners).

The extended dry period encompassing late summer/early autumn curtailed Haemonchus development to the degree that a number of producers have recorded surprisingly low worm egg counts in ewes monitored prior to lambing (early lambers). Typically, those mobs were last drenched in the January-March period and have been grazed conventionally i.e. largely set-stocked. It is very tempting to withhold pre-lambing drenches in ewes with low worm egg counts (less than 150 epg), particularly if lambing paddock worm contamination is considered low, however, the pre-lambing drench is a very important strategic treatment in this region, so an effective drench is always advised pre-lambing.

Editor's note: Ewes with low WEC at pre-lambing may be carrying a significant number of immature worms, and even a low WEC at this time provides the core from which a rapid population build up can occur in lambing ewes, which lose some of their natural resistance to worms. This spring, where most properties currently have waterlogged soil and the forecast is for a wetter than normal spring, is not the season to take a risk on lambing ewes.

Liver fluke assessment and treatment should be made over the August/September period on those properties known to have a history of the parasite. I feel that the detection rate of liver fluke infection has been higher than normal over the winter period, particularly in cattle. This is likely due to stock being forced to graze high-risk zones over the autumn period. 

 

DPI NSW

Armidale: Stephen Love, Veterinarian/Research Officer (Parasitology) (stephen.love@dpi.nsw.gov.au)

I have yet to see the summary of sheep WormTests for July from Veterinary Health Research (Armidale), but I have seen the July results from the NSW DPI State Vet Diagnostic Lab (SVDL) located at Menangle.  

The SVDL’s WormTests come mainly from central and southern parts of NSW, which are mostly ‘uniform/non-seasonal’ rainfall areas, and fewer from the north-eastern corner of the state (summer rainfall zone), which particularly favours Haemonchus (barber’s pole worm).

Generally, worm egg counts (WECs) were low to moderate, with just a few climbing to average egg counts of above 1000 eggs per gram (epg). And the higher counts tended to be Trichostrongylus (black scour worm)—but remember these results are mainly from uniform rainfall areas. Also, although Haemonchus infective larvae can survive on pasture in winter (albeit in declining numbers), its eggs are “delicate little princesses”—they don't tolerate cold and dessication (a bit like Fasciola hepatica [liver fluke] eggs).

The highest WormTest result from the SVDL was from the South East Local Lands Service (LLS), with the WormTest average count of 2200 epg (range: 1680–2720); larval differentiation (‘worm type’): Haemonchus 16%, Trichostrongylus 78%.  

The next highest count was from the Riverina LLS: 1191 epg (range 80–2560), Haemonchus 1%, Trichostrongylus 90%. Don’t always assume that worm egg counts of >1000 epg are going to be Haemonchus.

Now, August being an ‘A’ month, like April, means that you need to drench grazing livestock for liver fluke if it’s present on your property, and only if the ‘April' fluke drench is not sufficient to give good control.

For more information:
http://www.dpi.nsw.gov.au/content/agriculture/livestock/sheep/health/liverfluke-disease-sheep-cattle
http://www.wormboss.com.au/programs/sheep/nsw/appendices/liver-fluke-control.php

 

Bourke: Charlotte Cavanagh, VO (charlotte.cavanagh@dpi.nsw.gov.au)

There has been a slight increase in the number of WormTests conducted this month. Sheep have been showing signs of scouring, mainly due to grazing lush pastures; the result of the widespread rain over the past couple of months. Producers, however, need to be sure that the scouring is due to lush graze and not to worms by using WormTests, and, as many properties are currently shearing and sheep are in the yards, it’s the perfect time to conduct these tests and drench, if required. All sheep tested to date have been reported to be in good condition despite the scouring. 

WormTest results have come in from Euston in the south, through to Brewarrina in the east of our area, with a range in WormTest averages from 0–760 eggs per gram (epg). The majority of the worms have been scour worms. Only one culture showed 17% barbers pole. As the weather warms up and intermittent showers continue, producers need to be alert for signs of barber’s pole infections.  

Travelling around the district this week, I have noticed that there is a lot of water lying around providing areas for larval development on the fringes of waterholes. 

 

NSW LOCAL LAND SERVICES

Central West LLS

Coonamble: Jillian Kelly, DV (jillian.kelly@lls.nsw.gov.au)

Very few WormTests have been submitted to EMAI from the Coonamble area—it seems producers are using private companies to do their worm testing, and as LLS vets do not automatically receive copies of the results, it is difficult to accurately assess what is happening with parasite burdens.

Anecdotally, egg counts have increased since the recent rains, with some mild infections of black scour worm in the Gulargambone region. Worm testing identified barber’s pole worm egg counts of up to 1000 epg in the north of the LLS towards Walgett and Carinda.

Two cases of Ostertagia were diagnosed in weaner cattle. 

Dubbo: Evelyn Walker, DV (evelyn.walker@lls.nsw.gov.au)

Medium to high worm egg counts have been identified in sheep and goats in the last few weeks in the Dubbo area. Mild wet winter conditions have been conducive to larval survival. Barber's pole worm has been the predominant worm type.  

Producers are encouraged to check their flocks for worms now with a WormTest and drench if necessary.  

Forbes: Nik Cronin, DV (nik.cronin@lls.nsw.gov.au) and Belinda Edmonstone, DV (belinda.edmonstone@lls.nsw.gov.au)

Not many WormTests were performed in the Forbes area of the CW LLS in the last month, but there have been losses from scour worms in both sheep and goats. The spring will provide ideal conditions for scour worms and barber’s pole worms to survive and thrive in paddocks, so producers need to monitor their flocks by observing for clinical signs of worm infestations and to WormTest regularly. 

Nyngan: Erica Kennedy (erica.kennedy@lls.nsw.gov.au)

No WormTests were submitted to EMAI in the last month, however many producers have been using private companies who have been seeing high to very high egg counts particularly in last year's drop. Those animals on new cultivated pasture have generally had lower counts than those on native or older cultivated pastures. Egg counts have been as high as 5000+ epg. Cultures performed have indicated that the full spectrum of worms causing disease are present, but predominantly barber's pole and black scour worm. 

Producers need to be testing if they have not done so already, and with many sheep going through the yards for marking/weaning there is no excuse not to WormTest! Please consider having a culture performed so that you know what you're dealing with!  

Remember if a drench is required, do a follow up Worm Egg Count 10 days later to ensure the drench has worked effectively.  

 

Riverina LLS

Young: Elizabeth Braddon, DV (eliz.braddon@lls.nsw.gov.au) and Rahul Shankar, DV (rahul.shankar@lls.nsw.gov.au)

With spring-like conditions in the air, producers should have conducted worm tests in the 6–7 weeks prior to lambing, and where appropriate, given the lambing drench. Worm testing is best practice to determine the presence of worm burdens prior to lambing, and the potential for further contamination of paddocks. It also allows producers to prevent the occurrence of metabolic conditions in heavily pregnant ewes if conducted no later than 5 weeks prior to lambing. 

Due to the very wet conditions experienced throughout the region, some mobs of ewes brought in for lamb marking have required a drench. Their lambs have also showed scouring and some weight loss possibly due to worms and/or the quality of feed on offer. A WormTest, which can be obtained from your local LLS office, can provide a worthwhile check on current worm burdens. 

The above average winter temperatures have facilitated a continuance in worm activity. The main worm species at this time of year is the black scour worm, although there have also been a few reports of barber's pole worm in sheep. High risk groups such as weaners and pregnant ewes should be monitored regularly for signs of worms which are typically weight loss, scouring, a tail to the mob and at times, deaths. 

Lice populations have been on the rise, as is common during winter. Lice groups that have formed (and are forming) are actively encouraging members to participate in their program to better control of the lice situation in their area. Please contact your local LLS District Veterinarian for more information about lice.  

Wagga Wagga: Timothy Biffin, DV (timothy.biffin@lls.nsw.gov.au) and Emily Stearman, DV (emily.stearman@lls.nsw.gov.au)

Ideally, producers will have performed a WormTest 5 weeks prior to lambing and given an appropriate lambing drench as required. This is recommended for all producers to gain valuable monitoring information about the level of burdens in their ewe mobs going into lambing and the potential for further contamination of paddocks. If testing is done 5 weeks out from lambing, there will still be time for ewes to be brought in for drenching in the following week thus minimising the risk of metabolic events in heavily pregnant ewes when drenching is left too close to the start of lambing. 

In general, due to the very wet conditions, most autumn drop lambs are requiring a weaning drench, and this is recommended as a minimum standard. Best practice would be to conduct a WormTest and maybe even a larval culture to determine what worms are likely to be carried over into spring. With the current conditions, quite significant worm burdens are expected to develop as the high moisture, dense short pasture and warm weather starts to arrive in September.  

The usual worm species for this time of year in our area are typically the black and brown stomach scour worms (Trichostrongylus and Teladorsagia respectively), however, a few cases of barber's pole (Haemonchus) have also been detected recently. Barber’s pole infections would most likely be due to overwintering of infective larvae on pasture, so again, producers need to consider their upcoming management of high risk groups such as weaners and pregnant ewes.

 

Northern Tablelands LLS

Inverell: Andrew Biddle, DV (andrew.biddle@lls.nsw.gov.au)

Good winter rain across the Northern tablelands has set up conditions for a good spring. The arrival of warm weather could even turn the season into an early spring, which will be good for sheep and barber’s pole worm alike.

A good spring emphasises the need for well-prepared lambing paddocks as being critical to controlling worms, as overwintering larvae will be waiting to infect grazing sheep.

Few worm monitors have been conducted and results of those conducted indicate that barber’s pole is still ticking over. 

 

North West LLS

Narrabri: Shaun Slattery, DV (shaun.slattery@lls.nsw.gov.au)

Tamworth:  Bob McKinnon, DV (bob.mckinnon@lls.nsw.gov.au) and Heidi Austin, DV (heidi.austin@lls.nsw.gov.au)

Producers are advised to use the predictive BOM models to anticipate a build-up in worm burdens as few producers are worm testing.

Northern Slopes: Ted Irwin, DV (ted.irwin@lls.nsw.gov.au)

It is quiet on the northern slopes as far as worm burdens are concerned. Worm tests have not been conducted and there have been very few enquiries regarding drench choice.

 

South East LLS

Goulburn: Bill Johnson, DV (bill.johnson@lls.nsw.gov.au)

Several mobs of merino weaners have "hit the wall" in the past few weeks. They are pretty well grown, but now light in condition, around body condition score of one. Producers have missed ‘seeing’ the weight loss masked by the long wool growth. Some of the affected mobs have been supplemented, generally with hay, but paddock feed is short and green and apparently loaded with parasites. Mixed worm infections are present, including barber's pole, brown stomach and black scour worms. The type of worm involved doesn’t much matter; it is the damage they do to the gut lining in these nutritionally stressed young sheep that is important. The majority of sheep in affected mobs respond to worm drenching, although a significant tail remains after drenching in many mobs. These sheep are crook; they are weak, poor, and have a watery usually green smelly scour, typical of a bacterial gut infection. Bacteria establish in the worm-damaged gut wall. It pays to segregate these tail-enders. Treatment with an antibacterial drench will usually turn the tail around, providing high-quality pasture or concentrate supplements are fed. You'll need to discuss your case with a vet, to obtain a diagnosis and to access the antibacterial drench.

The highest worm egg counts continue to be from barber's pole worms, although a few mobs show high black scour and occasionally brown stomach worm counts. In most cases, worm egg counts show that ewes drenched before lambing haven't needed drenching at lamb marking.

Test for liver fluke if you have sheep that grazed paddocks with slow-flowing water during the warmer months, such as creeks and springs. Many properties with a history of liver fluke hadn't seen any evidence of them following a run of dry years through the early 2000s, but testing (blood, dung or post-mortem) has shown they have recently returned. Low levels of liver fluke silently rob profits, reducing wool growth, body weight, and milk production. Heavier infestations result in anaemia and death. Treating sheep and cattle for fluke before the warm spring weather arrives will help disrupt the liver fluke life cycle.