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

DPI NSW

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

It's a no brainer that we are in for a very wormy spring and summer in NSW, unless conditions suddenly turn hot and dry.

Over the last 3 months, rainfall for NSW has been ‘above average', 'very much above average' or 'highest on record'—depending on where you are in the state. Only sections of the coast have scored average rain, according to the Bureau of Meteorology.

Here are three things that will make worms of grazing livestock even more of a problem over the coming months:

It's not too late to remedy these things.

If you are weaning lambs in, say, late January, you can still improve the proposed paddock worm-wise.

Under current conditions, and if you are in the eastern half of NSW, start doing WECs every 4 weeks. Next time you drench, do a WEC on the day of treatment and retest 14 days later. Big benefits for relatively small costs.

Weaner cattle will be picking up lots of Ostertagia this spring in many areas. And Haemonchus as well, as a bonus, on the coast. Monitor WECs, but remember a low WEC in cattle may not always mean low worm burdens (sad, but true), hence the need to monitor growth rates—and other potential signs of ‘worminess’—as well. Like sheep and goat producers, many with cattle will be using less than highly effective drenches, due to resistance. Consider checking drench efficacy, the same as with sheep. If in doubt, use a cattle drench that is a combination of unrelated broad-spectrum actives. (There are only two of these currently on the market in Australia). In fact, using combination drenches are probably a good idea anyway.

And then there is liver fluke. Temperatures are generally now mild to warm and there is plenty of moisture. This is seventh heaven for liver fluke and its intermediate host snails. The fastest that fluke can complete one lifecycle is about 17 weeks, and they will just about achieve that under current conditions.

Alas, there is resistance to flukicides too, so keep that in mind. If checking flukicide efficacy, the time to test is on the day of treatment and again 21 days later. This is the simplest approach. (Get good professional advice on this). The appropriate tests are either a fluke egg count or the new coproantigen (faecal fluke antigen) test. The fluke antibody ELISA test is about the most sensitive of the tests for liver fluke, but it is inappropriate in this case because the antibody can take weeks to go down after all fluke have been cleared out by an effective treatment.

As always, get good professional advice. Some good sources: wormboss.com.au; NSW DPI PrimeFacts; a veterinarian or other worm-savvy adviser.

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

Broken Hill: Sophie Hemley, VO (sophie.hemley@dpi.nsw.gov.au)

Worm egg counts (WECs) from the Western District have returned mixed results over the past month.

As predicted, higher counts were typical of areas with the highest rainfalls and temperatures. One mixed-age sheep flock had an average WEC of 364 epg, with one sample in the group returning a strongyle count of 1800 eggs per gram (epg). A 1200-head goat flock grazing 5000 acres returned the highest average test result of 384 epg. Interestingly, four of the goats tested had 0 epg results, whilst another recorded a WEC of 2840 epg. Wide variation in one mob’s WormTest suggests that some goats may not have been drenched previously or they may have a reduced immunity to internal parasite burdens due to some other illness or injury.

Properties further west had the lowest WECs recorded, with a WormTest from one ewe mob with lambs at foot, returning a 0 epg WEC.

Producers are encouraged to complete regular WormTests to determine when/if drenching is necessary.

Increasing daily temperatures have caused a surge in blowfly numbers (Lucillia cuprina). Flystrike has been reported by a number of producers. Interestingly, pizzle strike has been frequently identified in wether lambs throughout the area. This finding highlights the importance of the appropriate application of fly preventatives

NSW LOCAL LAND SERVICES

Central West LLS

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

Harvest is in full swing, so livestock are largely left to their own devices at this time of year. This is worrying because, due to good rain and warm conditions, worm burdens will be on the rise, and barber’s pole worm may catch out the unsuspecting mixed-farmer who is busy harvesting.

We have been called out to cases of weak, staggery and dying weaner sheep in the last 2–3 weeks, but in all cases investigated so far, worms have not been the cause, instead M. ovis has been the cuprit. Regular worm testing and investigating cases of disease or death in livestock using your LLS District Vet or private vet is essential in these cases. There are also widespread issues with flystrike in sheep, as well as grass seeds in eyes, ears and carcases.  Flies are causing irritation and pink eye in cattle. We are yet to diagnose a case of Three Day Sickness in cattle, although we are still expecting to do so in the coming weeks due to the increased insect populations and reports of it (and M. ovis) in southern Queensland. 

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

Once again I have seen very few WormTest results, and have not had any clinical cases of losses due to worms. However, conditions have been right for larvae to survive to the L3 'infective' stage on pastures so producers need to be doing WormTests and if needed drench with an effective multi-active (combination) drench.

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

I have seen a significant increase in the numbers of worm counts being conducted over the last month: some counts have been very high, one count was nearly 22,000 eggs per gram (epg)! Some producers have taken the recommendation to request a larval culture with any worm test, and interestingly, the results have shown that there were more scour worms than barber's pole in the submissions.

In saying that, I fear the remainder of this year will be a perfect storm for barber's pole; plenty of soil moisture, very tall grass with sheep grazing low to the ground in between, and warm days.

If producers have drenched in the last couple of weeks they should perform a WormTest (WEC) before Christmas (in addition to their 14 days post-drench check). Weaner sheep seem to be the worst class of sheep affected by worms with clinical cases of deaths seen around the Nyngan region.

A reminder to producers that there is significant resistance to macrocyclic lactones (abamectin/moxidectin etc) in the Central West; http://www.flockandherd.net.au/sheep/reader/anthelmintic-resistance-survey.html 

Riverina LLS

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

The wet winter/spring is slowly starting to dissipate and the drier weather is doing a world of good for those looking to harvest over the coming weeks. 

The abundance of high-quality spring feed is still on offer on many properties throughout the district. Many producers have begun to join their ewes and rams.

Between now and Christmas is when producers typically consider giving their first summer drench and also identify paddocks for their weaners. With the warmer weather predicted from now till March/April of next year, producers are encouraged to consider preparing low worm-risk paddocks for the following season: http://www.wormboss.com.au/news/articles/nonchemical-management/why-prepare-low-wormrisk-paddocks.php

Frequent monitoring of worm egg counts for any mobs that are showing any signs of weight loss and excessive scouring is strongly encouraged. Our offices stock worm egg count test kits and we encourage producers to pick up a worm egg test kit or seek advice from a district veterinarian should they feel that any of their mobs are experiencing production issues associated with internal parasites. 

Blowfly strike preventative measures are being employed by many throughout the district, and producers are reminded to be mindful of Export Slaughter Intervals and Withholding Periods for the respective chemicals they are using. It is important to be particularly mindful of sheep that may be affected by strawberry footrot or foot abscess. These animals should be inspected individually and where appropriate fly strike preventative chemicals should be applied to their wounds. 

Fleece rot and lumpy wool have been found in mobs brought in for shearing. Appropriate treatments, and the warming weather is allowing both conditions to dissipate from affected sheep. Again where necessary, fly strike preventative treatments should be applied to any sheep that may require it.

Mosquito populations have exploded in numbers due to the vast amounts of standing waters left laden on properties. Ross River Fever (http://www.health.nsw.gov.au/Infectious/factsheets/Pages/ross-river-fever.aspx) and Barmah Forest fever (http://www.mhcs.health.nsw.gov.au/publicationsandresources/pdf/publication-pdfs/7095/doh-7095-eng.pdf) have been detected in mosquito populations recently.

A warning: Mosquitoes are not only a concern from an animal health perspective but also from a public health perspective. All producers are advised to cover up by wearing long sleeve shirts and pants and to apply adequate and appropriate mosquito repellent when working outside. 

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

With wet and warmth there will be worms! (amongst other things).

Given the current climate across around Wagga Wagga, parasite management should be in focus for all livestock producers. Internal parasites are able to thrive when there is short prolific ground cover (to protect from UV radiation), high moisture/humidity (to protect from desiccation) and mild-warmer weather (to increase metabolism). As expected, evidence of increased worm activity is starting to be observed around the district.

What should producers be doing at the moment?

Worm Testing: At this time of year producers need to know when their sheep need drenching. This should not be based on pub talk or blind assumptions, but rather, a faecal worm egg count (WEC). This is cheap and simple test. Although there are some inconsistencies with older sheep, the results from a WEC will give a fair indication of the current worm burden, from which you can make informed decisions of whether to drench or not.

What else could producers be doing at the moment?

Some producers monitor flocks with WECs and yet do not need to drench very frequently. This is due to some other sound parasite management practices such as:

Searching through WormBoss will give you significant, useful information surrounding each of these topics.

Northern Tablelands LLS

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

Seasonal conditions are certainly favourable for cattle, sheep, barber’s pole and fly (Lucilia cuprina).

Worm egg counts (WEC) are clearly on the increase, although there is still a lot of variability within the samples making up the WEC submissions. This may be host resilience and resistance, the individual sheep’s grazing habits, or just normal variability.

North West LLS

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

I have just seen a case of heavy worm burdens in Boer goats near Manilla, which resulted, according to the owner, in quite a few deaths from a herd of 300. Although no differential cultures were done it is presumed the burden was mostly haemonchus. However, the goats were scouring heavily so a decent burden of scour worms were probably also present. The case is interesting because losses began in August when it was cold. Goats were given a Q drench, but there was no visible improvement in their condition (we were only contacted by a private vet on 11/11/16). However, following the latest drench with Zolvix (12/11/16) and movement to a fresh paddock (13/11/16), there has already been a significant improvement in the mob.

Obvious warnings were given about the responsible use of Zolvix (given under veterinary direction), and a faecal worm egg count in a month has been recommended. Stock management was also an issue here.

Editor's note: In this case, the situation leading to the deaths has not been provided in this report and so deaths cannot simply be attributed to the drench. Time since the drench (prior to the deaths) and the product type and dose rates used have not been provided, likewise, the extent of contamination of the paddock (very important) used after the Q-Drench administration is unknown, and effectiveness of Q-Drench on this property is unknown.
This is a good example of where (a) regular WormTests would have picked up an emerging problem well in advance of numerous deaths and (b) a DrenchCheck - that is a WormTest 
(with a culture) done before as well as 14 days after the drench would have given a good indication of the effectiveness of the drench and (c) 3-yearly Drench Tests would indicate effectiveness of a range of drenches.

No other cases have been reported. Other faecal egg counts for the region have only shown moderate counts in the hundreds.

Outlook for the rest of November: cautious.

Moree: Justine McNally, DV (justine.mcnally@lls.nsw.gov.au)

On the fly front: they are BAD.

Lots of people are having to treat sheep for fly, whereas in the past few years, treatments were not required. Strike has been seen in lambs and adults. The massive load of flies up here—blowflies, blue/green strike fly and millions of bush flies, has also led to some issues with post marking septic arthritis. Lots of producers have called us, so I think they are managing fly well, and are trying to let others know it is about, so those who are not sheep operators in the main can increase their surveillance for strike etc. 

Worm numbers are still on the move so quite a few producers are needing to drench. There has been a slight increase in those conducting pre-drench worm egg counts, and hopefully will go on to also conduct post-drench worm egg counts.

Drench check: Producers are advised of the extreme need to establish a base line worm egg count level before drenching as a comparison for the post-drench worm egg count to assess drench–resistance. 

Murray LLS

Albury: Scott Ison, DV (scott.ison@lls.nsw.gov.au) and Mark Corrigan, DV (mark.corrigan@lls.nsw.gov.au) and

Deniliquin: Linda Searle, DV (linda.searle@lls.nsw.gov.au)

In the western part of the district, only one faecal egg count was submitted in October. It was from clinically normal, fat healthy Dorper sheep that had been moved down from further north in the state.

Their average egg count was 325 (range of 0–1080) eggs per gram (epg) strongyle pooled, and 8 (range 0–80) epg Nematodirus. The larval differentiation showed that 36% of the worms were barber’s pole worm, 48% were black scour worm, 14% were small brown stomach worm, with small intestinal worm and large intestinal worm both making up 1% each.

In the eastern part of the district, submissions were from the lactating ewe mobs on one property. Of the 3 submissions, two were from adult ewes and one from maidens. The average count from the maidens was 120 epg strongyle and 20 epg Nematodirus. One adult mob had an average of 340 epg strongyle and 20 epg Nematodirus with larval differentiation returning 74% black scour worm, 25% small brown stomach worm and 1% large intestinal worm. The other adult mob had an average count of 240 epg strongyle and 0 epg Nematodirus with larval differentiation of 98% barber’s pole worm and 2% black scour worm.

South East LLS

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

Pastures bolted following a few warm days and are now starting to hay off in time for the first summer drench. What drench to use depends on what worms are present in your sheep, with about half our flocks now showing substantial proportions of barber's pole worms. Weaning paddocks will be a particular risk, being those pastures with the most residual green feed coming into summer. This is expected to provide on-going protection for barber's pole larvae. Keep a close check on worm levels with monthly worm egg counts, to try to avoid any nasty surprises.

A few mobs of un-weaned lambs have enough brown stomach and black scour worms to cause scouring and slow growth rates. They were born on less than ideal pastures, contaminated by young sheep in autumn. One owner wanted to drench the lambs and return them to the same paddock with their mothers, while they regained weight; after all, there was still good feed in the paddock. But drenching and weaning, combined with moving the lambs to a low-worm paddock, is a lot better.

Warning: A recent case highlights one of the pitfalls with monitoring. One of our larger producers sampled three mobs of similar-age merino ewes as part of his routine worm monitoring. Two of the mobs had average counts less than 100 eggs per gram, while the third had an average count greater than 2400epg. Many of us take short cuts with monitoring, often using the results from one mob as a measure for all mobs, especially where recent treatment history is all the same. But it pays to remember that at most times of the year there are way more worms on the paddock than in the sheep, so decisions about monitoring need to take previous grazing history of the paddock into account as well. It would have been easy to miss this emerging worm crash otherwise.

Blowflies are quick to strike any sheep with smelly, wet dags, especially crossbred lambs. Unfortunately, it is becoming hard to find struck sheep in the long grass, so preventive treatment of the mob by way of a "bung-hole crutch" is recommended. There are a number of options for treating any breech strike after crutching, but be aware that some chemicals have long withholding periods prior to slaughter.

Warning: Sheep dipping contractors are working flat out to catch up on sheep shorn throughout a wet October. Contractors are still frequently asked to use diazinon in their plunge and cage dips, as producers hang onto the notion that diazinon is the only reliable dipping chemical. One particular immersion cage dip has sufficient safety features to comply with a permit to use diazinon, while the chemical is banned from use for lice control in all other wet dips because of human health risks. There are several safer alternatives available, which are also easier to use and effective.

Central Tablelands LLS

Mudgee: Nigel Gillan, DV (nigel.gillan@lls.nsw.gov.au)

Worm egg count results from the Mudgee area have been mixed. Those performing larval typing have, in some cases, found a reasonably high percentage of scour worms in addition to the usually more common barber's pole. Just recently I received reports of illness and deaths likely due to barber's pole.

Producers who are planning weaning paddocks for the next few months should select those likely to have low larval contamination, since weaner sheep are generally very susceptible to internal parasites.