WRML. Trifecta. Monepantel-llamas. Ag smartphone apps. Cattle parasite atlas.Recovery of fluke eggs.Q&A-egg counting.Other.

To WormMail (WRML) list (recip. undisclosed. ~ 400 subscribers).

In this issue (2014-08-29):

· ‘Trifecta’ multi-combination broad-spectrum cattle and sheep drench released

· Dose rate of monepantel (MPL) for llamas

· Useful Ag-related apps for smartphones

· Cattle Parasite Atlas – MLA

· Recovery rates of Fasciola hepatica eggs

· Q&A on worm egg counting

· Other…..

· Prof Marmion and Q Fever

Trifecta multi-combination broad-spectrum cattle and sheep drench released

Coopers‘ new triple active oral drench for sheep and cattle – ‘Coopers Trifecta’ – was registered recently. It was available in stores from 25 August.

‘Trifecta contains the actives abamectin, oxfendazole and levamisole, as well as selenium and cobalt and is registered for use in sheep (over 15 kg and 6 weeks of age) and cattle (over 100kg and over 16 weeks of age) for the control of internal parasites. The dose rate for both species is 1ml/10kg liveweight and it will be available in a 10L drum. Coopers will also have available an 8ml drench gun for sheep and a 60ml drench gun for cattle (with or without a floating hook).’

‘Trifecta has the following withholding periods:

WHP meat (sheep and cattle) – 21 days

ESI Cattle – 21 days

ESI Sheep – 28 days

MILK – Do not use in cows/ewes which are producing or may in the future produce milk that may be used or processed for human consumption.

‘Coopers is currently working towards establishing a treatment to calving interval.’

Coopers Trifecta is the only triple (broad-spectrum) active combination drench available for use in cattle in Australia.

The only other combination (of broad spectrum actives) available for cattle in AU is ‘Eclipse’ (Merial), which is a pour-on (topical) product containing abamectin + levamisole.

The only other cattle drench in AU, that I can think of/find, that contains a macrocyclic lactone and is an oral drench, is ‘Fasimec’ (triclabendazole + ML; Novartis) and it’s equivalent/’mirror’ product, ‘Triclamec’ (Youngs).

There is general consensus among most experts (at least in Australia/NZ) that using a combination of unrelated broad-spectrum actives of similar persistency and with similar spectra of activity – especially if used as part of an integrated approach to worm control (including management of refugia) – is a preferred way to maintain high drench efficacy/manage resistance of worms of grazing livestock.

There is also evidence that, at least in some situations, and with everything else being equal, that oral formulations of a drench outperform the injectable and topical equivalents. I am thinking of the Leathwick and Miller (2013) paper here, but note in that situation the differences in the efficacies of the the formulations types was

D.M Leathwick & C.M. Miller (2013), Efficacy of oral, injectable and pour-on formulations of moxidectin against gastrointestinal nematodes in cattle in New Zealand. Vet. Parasitology 191 (2013) pg293-300.

D.M. Leathwick & R.B. Besier (2014), The management of anthelmintic resistance in grazing ruminants in Australasia – Strategies and experiences. Vet. Parasitology 204 (2014) pg44-54.

Dose rate of monepantel (MPL) for llamas

Dadak and others (2013) conducted studies to see what dose rate of MPL was efficacious in llamas. The dose rate for sheep is 2.5mg/kg liveweight.

The authors concluded: “.. monepantel is considered (to be) highly effective in llamas naturally infected with GINs (gastrointestinal nematodes), and is recommended at a dose rate of 7.5mg/kg BW. It remains to be investigated whether the efficacy of monepantel is comparable in alpacas at the dose rates studied.”

As always you need to read the full paper for yourself.

Note also that, in Australia, monepantel (Zolvix(R), Novartis) is only registered for use in sheep and that use in other species is ‘off-label’. More information on ‘off-label use and “prescription” by veterinarians:

http://www.dpi.nsw.gov.au/agriculture/livestock/residues/stock-medicine

A. M. Dadak, H. Asanger, A. Tichy, S. Franz (2013). Establishing an efficacious dose rate

of monepantel for treating gastrointestinal nematodes in llamas under field conditions.Veterinary Record 2013;172:155. http://veterinaryrecord.bmj.com/content/172/6/155.1.extract

(Thank-you Dr Paul Mason for the ‘heads up’ regarding this paper).

Useful Ag-related apps for smartphones – from SheepConnect-Tasmania

https://gallery.mailchimp.com/d8262befda5125340f6c51851/files/SCT_2014_2_Aug_p4_5.pdf

Cattle Parasite Atlas – Meat and Livestock Australia

This is a useful resource. I am pasting the link as it is not always easy to find things on the MLA website. (Sorry, JS).

http://www.mla.com.au/Livestock-production/Animal-health-welfare-and-biosecurity/Parasites/Cattle-parasite-atlas

However, I must say I have trouble with the suggested program for the NSW Northern Tablelands: perhaps someone can explain it to me sometime. Or, maybe I should drink more coffee.

Recovery rates of Fasciola hepatica eggs

In Happich and Boray’s paper in the Australian Veterinary Journal, 1969 (short title: quantification – chronic fasciolosis), there is an interesting table describing the recovery rates of fluke eggs by floatation and sedimentation techniques. The table is attached. The recoveries ranged from 1% (in a flotation technique) up to around 40% (sedimentation technique).

​‘Table 1 shows that only 2 out of 75 samples with 10 epg were positive by the flotation method, but eggs were detected in all samples by sedimentation.’

‘In the flotation technique only about 1% of the eggs were recovered compared with about one third of the total number of eggs by sedimentation.’

‘More eggs (about 40%) were recovered by sedimentation if detergent were added, but the amount of sediment increased considerably and the examination was more difficult.’

‘In positive samples, the average calculated epg was about one-third of the actual epg by both flotation and sedimentation.’

‘Eggs were not recovered from 55 samples, and only asingle egg was recovered from 17 samples containing 10 epg by flotation. Only 1 or 2 eggs were recovered by flotation from 32 samples (43%) containing as many as 100 epg. At both 10 and 100 epg the recovery from a large proportion of samples was appreciably below the

average calculated epg. More uniform recovery was achieved from the samples containing 1000 epg.

‘With sedimentation the variation of recovery from sample to sample with 10 epg was large, but some eggs were recovered from all samples. In 84% of the samples with 100 epg and 77% of the samples with 1000 epg the recoveries deviated only +/_ 30% from the average.’

The flotation solution used was potassium mercuriiodide​.

(Mercury salts have the advantage of relatively high specific gravities (see below), but I think they have fallen out of favour for safety reasons??).

(Thank-you Maxine Lyndal-Murphy for bringing this to my attention, again).

Q&A on worm egg counting

Below is some information I gave to a person (private vet practitioner) who attended one of NSW DPI’s egg counting courses. I don’t imagine for a moment that my answer is necessarily 100% accurate or exhaustively accurate. It may however be useful as a starting point for someone wanting to learn more about these parasitological techniques.

The question: “Is there an all in one solution that will float liver fluke? (A producer believes there is and we are not aware of such a solution)”.

​The answer I gave: ‘Yes, I was thinking ZnSO4 (zinc sulphate) might be one of them and it is. I consulted some old parasitology references on this’.

‘From the ‘MAFF (Ministry of Agriculture Fish and Food (United Kingdom)) Manual of Vet. Parasitology Laboratory Techniques), 3rd Ed., 1986; ISBN 0 11 242724 3))​ ​: Saturated Zn SO4 solution (Specific gravity (SG) =1.364) is recommended for floating Fasciola eggs (e.g. using a ‘sensitive floatation technique’) as they ​won’t float in sat. Na Cl (SG=1.204 (1.19 at 20 degrees C according to Thienpont (Thienpont D et al ~ 1979-‘Diagnosing helminthiasis through coprological examination’ – Janssen Research Foundation -Belgium)’.

‘Now, this answers your MgSO4 answer as well. MAFF go on to say that say MgSO4 (SG=1.290 (1.28 at 15 deg according to Thienpont)) is similarly recommended (instead of NaCL) for Metastrongylus eggs, and indeed sat. MgS04 can be used to replace NaCl and will give a better recover of some types of eggs such as Trichuris, Capillaria and Ascaris. If the eggs are required for other procedures (e.g. hatching), then sat. sucrose solution (SG=1.286 (1.12 at 15 deg according to Thienpont)) is better as it has less deleterious effects on egg viability than others’.

‘A disadvantage (MAFF says) of using sat. ZnSO4 to float Fasciola ova is that the shells collapse or at least get misshapen (as do Ballantidium cysts), however they remain easily recognizable – the same clear yellow-green of the shell and the same size – but this collapse can lead some eggs to sink again, so it’s important to proceed with counting once the floatation procedure has started. Thienpont however says the solutions used to float trematode eggs cause shrinkage and discolouration, and the operculum will often disappear. But they can still be differentiated from nematodes, however different trematode eggs (e.g. Fasciola v pararamphistomes) can’t be differentiated).’

‘By the way, the NSW DPI labs (at least when I was in the system) use a sedimentation technique for fluke egg counts.’

‘(Most if not all eggs lose shape in concentrate solutions (i.e. SG> 1.0) over time).’

‘In short, all flotation solutions have their pros and cons. Sat. NacL is cheap and easy, not much will grow in it, but it is murder on lab equipment made of metal (e.g. mechanical stages on microscopes, and metal mechanical counters -which were used in the olden days (when I was in a lab) – and heavy eggs (e.g. trematodes and Metastrongylus) won’t float in it. Sucrose I imagine is messy, but I have never used it. I am not sure what the cons of sat MgS04 might be. Some solutions are toxic .e.g. mercury salt solutions (potassium mercury iodide, which is also very expensive (Thienpoint et al), but has an SG of 1.44 ! at 15 deg. (Thienpont).’

‘From Thienpont et al: ‘in practice, all cestode and nematode eggs (except Metastrongylus) float in fluids with SG between 1.10 and 1.20. Trematode eggs require SG 1.30 – 1.35.’

If there was one parasitology text that ‘does it all’, I would have merely pointed this inquirer to that text.

Now, when it comes to practical information on sheep worm management in Australia, WormBoss comes close to ‘doing it all’. I am unbiased of course. FlyBoss and Liceboss, the other two under the ParaBoss umbrella (parasol?), may well do likewise, but I am less competent to comment on ectoparasites.

Other…..

Ancient vs modern wheat and irritable bowel syndrome (IBS) etc

Effect of Triticum turgidum subsp. turanicum wheat… [Br J Nutr. 2014] – PubMed – NCBI] http://www.ncbi.nlm.nih.gov/pubmed/24521561?dopt=Citation

Related: non-coeliac gluten sensitivity (NCGS), IBS, wheat allergy (WA), and coeliac disease (CD) etc: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3820047/

Especially for those with CD, one expert said that saying that ancient wheat is better than modern wheat was like saying low tar cigarettes are better ‘full’ tar cigarettes. Just avoid them both.

Higher cholesterol linked with lower risk of death in the more mature person

Here is something for the elderly (all those older than 61.2 years of age)

http://www.drbriffa.com/2014/08/15/evidence-links-higher-cholesterol-with-lower-risk-of-death-in-older-individuals/

This is just to confuse you even more – in case dementia wasn’t enough..;-)

Sign of the times

From a friend currently in Ireland:

‘On the main street, O’Connell Street, I just witnessed a large pro-cannabis demonstration. One of the best placards read, “My sign is better than yours.”

Professor Marmion – the man responsible for the introduction and use of the world’s only Q Fever vaccine

Vets, farmers and meat workers are among those most at risk of getting Q fever.

The following is on Q-fever expert, Prof. Marmion, who died recently.

http://www.abc.net.au/news/2014-08-19/colleagues-remember-q-fever-vaccine-crusader-barrie-marmion/5682202

Regards,

SL. 2014-08-28

 

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WRML.20140820.Wormfax. alpaca worms-NZ. FBZ medicated blocks.Fasciola research-Victoria.Combat departs.Dung beetles.Milk and wood glue. A theory’s 4 stages.

To WormMail mailing list (recip. Undisclosed)

cc G Rawlin​

In this issue:

· WormFax

· Worms in alpaca in NZ. Update from Prof. Bill Pomroy

· Fenbendazole medicated blocks, feed intake and worms (Dr L Kahn)

· Research into liver fluke in irrigated areas of Victoria (Dr G Rawlin)

· Combat (Naphthalophos) discontinued

· Dung beetles

· Milk, wood glue and hearing

· The four stages of a theory (Haldane)

WormFaxNSW

The latest issue (July/August) has been published to the website: http://www.dpi.nsw.gov.au/aboutus/resources/periodicals/newsletters/wormfax

WormFax is a monthly summary of sheep WormTests from around NSW.

Eye-balling the sheep WormTest results from two of the major labs in NSW (VHR and EMAI), I see there are some relatively high worm egg counts in various locales, even in areas such as north eastern NSW and southern Queensland which have had record or near record low rainfall for the last 12 months.

So, why the high counts (e.g. >2000) in some flocks, including those in drought-affected areas?

Of course there are a number of reasons, but a common one is the unwitting use of drenches rendered ineffective by resistant worms.

Although testing drench effectiveness is cheap and easy (see info on DrenchCheck) farmers like everyone else are afflicted by busy-ness: driven by the tyranny of the urgent rather than guided by the truly important.

Still, simple things like using drenches known to be effective through on-farm testing reaps huge rewards.

Another way to make great gains is to get familiar with and follow Your Program in WormBoss. It’s very easy to read, and not too hard to apply. But, like all important things, it does take some time.

Worms in alpaca – New Zealand

A recent comment from Professor Bill Pomroy of Massey University:

“…there have been several documented deaths due to haemonchosis. We have recently identified an abomasal species Trichostrongylus askivali in alpacas which is a species we have seen in red deer. There was no suggestion the numbers involved were pathogenic. The particular alpaca property involved apparently did not have any farmed deer so the importance is unclear. Camelostrongylus mentulatus is an Ostertagia-like parasite that lives in the glandular stomach region of camelids. It was first identified in New Zealand in 2003 and is now widespread.”

Fenbendazole medicated blocks, feed intake, worms and refugia

From Dr Lewis Kahn, UNE:

Fiona Fishpool investigated self-medication with fenbendazole blocks in sheep. She observed some interesting behaviours regarding block intake in response to infection. A significantly greater proportion of infected animals consumed the block and when the block was curative (i.e. BZ susceptible infection) the infected animals consumed more block. The pattern of non-eaters raised the possibility of built-in refugia.

Some references:

Fishpool, F. J., Kahn, L. P., Tucker, D. J., Nolan, J. V., & Leng, R. a. (2012a). Fenbendazole as a method for measuring supplement intake in grazing sheep. Animal Production Science, 52(12), 1142. doi:10.1071/AN12008

Fishpool, F. J., Kahn, L. P., Tucker, D. J., Nolan, J. V., & Leng, R. a. (2012b). Voluntary intake of a medicated feed block by grazing sheep is increased by gastrointestinal nematode infection. Animal Production Science, 52(12), 1136. doi:10.1071/AN12104

Fishpool, F., Kahn, L. P., Tucker, D. J., Nolan, J., & Leng, R. (2011). Fenbendazole as a possible marker of supplement intake in sheep. Proceedings of the New Zealand Society of Animal Production, 71(i), 1–4. Retrieved from http://www.nzsap.org/ym/ab11004.pdf

Research into liver fluke in irrigated areas of Victoria

Dr Grant Rawlin is the Research Leader in Veterinary Pathobiology with Victoria’s Department of Environment and Primary Industries.

Grant and the group he works with from La Trobe University are investigating various aspects of liver fluke (Fasciola hepatica) control, especially in the irrigated areas of Victoria. Fluke in these areas is becoming more of an issue, with triclabendazole (TCBZ) resistance and very high burdens in dairy herds, particularly in Maffra (south-eastern Victoria), being a major concern.

The group is estimating production losses from fluke in the district. Early results indicate the losses are significant.

The team has a PCR designed to track the infective stage of Fasciola around the irrigation district onto farm. The aim is to get some modern tools (that Boray did not have) to better understand the ecology and management options of liver fluke.

The PCR is fairly well advanced and working well in water but there are some issues to work out related to the presence of grass which affects the release of DNA from metacercariae.

The group is also working with apple and pear entomologists whose approaches to integrated pest management are of interest. The research team hopes to pick up where Boray left off before TCBZ came on the scene and impacted work on ecological approaches to Fasciola management.

Combat (naphthalophos) discontinued

Virbac has advised that, for commercial and other reasons, they are withdrawing the naphthalophos-based sheep drench, Combat.

Dung beetles

Article in The Land:

http://www.theland.com.au/news/agriculture/cattle/beef/dung-deal-french-beetles-do-our-dirty-work/2709001.aspx?storypage=0

Of interest to parasitologists also.

Milk, wood glue and hearing

‘Something I read recently: ” Milk doesn’t look very good in photographs: the white liquid you see in advertisements is usually a mixture of milk and PVA glue”.

I have heard PVA wood glue (e.g. ‘Aquadhere®’) is good for your ears / preventing wax build up / hearing as well, or is that ‘Aquaear®’?

The four stages of a theory

“I suppose the process of acceptance (of a theory) will pass through the usual four stages:

1. This is worthless nonsense

2. This is an interesting, but perverse, point of view

3. This is true, but quite unimportant

4. I always said so.”

Attributed to JBS Haldane.

 

Regards,

SL

 

WRML.2014-08-12.Teladorsagia technicalities etc

To WormMail mailing list (recipients (~400) undisclosed)

In this issue:

  • Teladorsagia technicalities
  • Old time fluke (chemo)therapy
  • Chemclear
  • OCR Documents for Free in Google Drive
  • Parachute use to prevent trauma – evidence-based??
  • Sexual suicide in honey bees
  • European Union Directive No. 456179 on micturation
  • Questions – from ‘Oestrus ovis’

Teladorsagia technicalities

In a recent edition of WormMail I said this:

“In the first version I also did not indicate that the resistance to brown stomach worm involved two species of that worm (Tel. circumcincta and Tel. trifurcata). This might be of interest to just a few.”

In response, a colleague from NZ, consultant parasitologist Dr Paul Mason, offered this comment (with permission to share (all of it)):

Hi Steve

Tel. trifurcata (and Tel. davtiani) are minor morphs of Tel. circumcincta, so they are all really one species.

Pharmaceutical companies like to treat them separately as it increases the hit rate on the label claim.

Parasitologists like to treat them separately as we like to be asked to count them separately.

Major and minor morphs are common in the Ostertagiinae (Ostertagia-like worms). …..

Regards

Paul

27 June 2014, Christchurch, NZ

Old time fluke (chemo)therapy

A paper by Boray and Pearson (1960) came up in discussion with parasitology colleague Maxine Lyndal-Murphy of Queensland.

Just the introduction is interesting. Here is my summary (hopefully free of egregious errors):

  • carbon tetrachloride discovered to have an anthelmintic effect on hookworm in dogs (Hall, 1921).
  • carbon tetrachloride found to work against intestinal flukes in dogs (Jeffreys, 1922), and Fasciola hepatica in sheep (Ernst, 1925; Montgomerie, 1926) – an historic step in effective treat. of fluke
  • Thienel (1926) announced hexachloroethane killed liver fluke in cattle
  • up to 1960s, these chlorinated hydrocarbons the only effective chem treats. for F hepatica in sheep/cattle
  • but, not always effective; and sometimes toxic incl death
  • sodium fluosilicate reported effective against oesophagostomosis – sheep (Mönnig,1933) (Yes, the paper says fluosilicate, not fluorosilicate)
  • Parnell (1939): sodium fluoride and sod. silicofluoride effective against free-living stages of bursate nematodes of horses and sheep
  • Sod. fluoride very effective against Ascaris suis in pigs (Habermann et al, 1945) and widely used in pigs until intro. of piperazines
  • Trifluorotrichloroethane had efficacy against intest. parasites of dog (U.S. Bureau Animal Industry, 1933)
  • Fluorine-substituted phenols (fluorophenols) found to paralyse A. suis in vitro faster than chlorophenols (Dunker, 1950).
  • Toxicity of chloro compounds found to be related to number of chlorine atoms and to ratio of chlorine to carbon atoms in the molecule …. the fluorine is so tightly bound in an organic molecule to the carbon that little lionization occurs. Substitution of fluorine for chlorine in the methane series decreases toxicity (Jenkins et al, 1957). ‘This may explain why hexachloroethane is less tox. than carbon tet. and suggests tetrachlorodifluoroethane may be even less toxic.
  • this paper records the successful use of tetrachlorodifluoroethane against F hepatica in sheep.

Boray, J. C. and Pearson, I. G. (1960), The anthelmintic efficiency of tetrachlorodifluoroethane in sheep infected with Fasciola hepatica. Australian Veterinary Journal, 36: 331–337

Carbon tet: “…originally synthesized by the French chemist Henri Victor Regnault in 1839…….It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent. It is a colourless liquid with a “sweet” smell that can be detected at low levels… Stamp collectors used carbon tet to reveal watermarks on postage stamps without damaging them………The production of carbon tetrachloride has steeply declined since the 1980s due to environmental concerns and the decreased demand for CFCs, which were derived from carbon tetrachloride………..it became apparent that carbon tetrachloride exposure had severe adverse health effects, such as causing fulminant hepatic necrosis ……………..Carbon tetrachloride is one of the most potent hepatotoxins (toxic to the liver), and is widely used in scientific research to evaluate hepatoprotective agents”…. ( I personally have seen hepatopathies in sheep at necropsy after being drenched with CCl4 for liver fluke (one or two older farmers (in the 1980s, Glen Innes district still used it)….”..Carbon tetrachloride persisted as a pesticide to kill insects in stored grain, but in 1970 it was banned in consumer products in the United States…………..” Source: http://en.wikipedia.org/wiki/Carbon_tetrachloride

According to parasitipedia, triclabendazole was released by Ciba-Geigy (which became Novartis) in the 1970s.

Some information on current flukicides:

Chemclear

For your information:

http://www.chemclear.com.au/

“ChemClear provides Australian agricultural and veterinary chemical users with a collection and disposal pathway for their unwanted chemcials.”chemicals’

OCR Documents for Free in Google Drive

http://computers.tutsplus.com/tutorials/how-to-ocr-documents-for-free-in-google-drive–cms-20460

(For this to work, the image, whether in a JPEG or PDF etc, has to be reasonably good e.g. it didn’t work on a PDF of the Boray and Pearson (1960) paper).

Parachute use to prevent trauma: evidence-based??

http://www.bmj.com/content/327/7429/1459

The above was referred to by Feinman (Richard D) et al who questioned how far one should go with the need for evidence (e.g. from randomised controlled trials) for medicine (incl. veterinary medicine).

Sexual suicide in honey bees

http://insects.about.com/od/antsbeeswasps/qt/Honey-Bee-Mating.htm

Something I learnt recently (from an entomologist (Dr Garry Levot) when we attended the same meeting).

What I don’t know: did I never know this, or did I forget it? (or both? 🙂

European Union Directive No. 456179 regarding micturation

In order to bring about further integration, all citizens of the United Kingdom of Great Britain and Northern Ireland must be made aware that the phrase ” Spending a Penny” is not to be used after 31 December 2014. From this date onwards, the correct term going forward, will be: “Euronating”.

Questions – from ‘Oestrus ovis’

(see attached)

e&oe

Regards,

SL

Veterinarian / Parasitologist

QUESTIONS-from Oestrus ovis NZ 2008.docx

WRML: Article on monepantel resistance in The Land newspaper, 24 July 2014. Hypotrichosis in Suffolks

To: WormMail (WRML) mailing list.

This article appeared in the Vet Talk column in The Land recently. Unfortunately it was truncated, the last three paragraphs (which gave this goat owner due credit) being deleted.

Article of Vet Talk, The Land (for Issue 24 July 2014, due by 18 July)…slightly modified 25/7/14 for Paraboss News (added info re worm genera involved)

First confirmed case of resistance to new drench in Australia

– what does it mean?

Stephen Love

Veterinarian / Parasitologist

NSW DPI Armidale

A case of resistance to the sheep drench Zolvix® (monepantel (MPL), Novartis) was recently confirmed on a goat farm in NSW. This appears to be the first and only confirmed occurrence in any livestock in Australia. MPL is a brand new type of drench, released in this country in 2010. This case is a good reminder that producers need to focus on best practice worm management so as to keep drenches alive for as long as possible, as well as optimising productivity and livestock health.

The world launch of MPL was in New Zealand in autumn 2009.Their first cases of resistance to the drench, also on goat farms, were reported in 2013. So far no cases have been reported in sheep.

It’s a long time between drinks when it comes to new drench actives coming onto the market. MPL, which is only registered for use in sheep, was the first entirely new type of drench to be released in Australia since the macrocyclic lactone (ML, mectin) drench family made its appearance in 1988.

In this Australian case of resistance, MPL was still highly effective against barber’s pole worm, but efficacy against black scour worm was declining and very low against brown stomach worm.

It is unclear what this case means for the sheep industry, but we know that sheep, goats and alpacas share many of the same worms, so we have to assume these resistant goat worms can successfully transfer to other animals including sheep.

There are two ways of getting resistant worms: importing someone else’s, or breeding your own.

So, how do you keep resistant worms out? A good quarantine procedure is needed. This includes using MPL as well as at least three other unrelated drench actives as a quarantine treatment. ‘Overkill? No, because we know for example that there are now sheep worms able to resist even multi-combinations containing 3-4 actives.

On-farm you can slow the development of resistance to worms by using drenches only when required, at the right dose, and as part of a rotation of effective drenches or, even better, by using combinations of unrelated drench actives.

To reduce reliance on drenches, also employ strategies to improve the ‘immunity’ of sheep to worms, notably through good nutrition and good genetics, the latter usually being achieved by using rams with favourable breeding values for worm egg count (ASBV WEC). Reduce exposure to infective larvae on pasture using grazing management, i.e. getting time and nature on your side.

Also aim to keep some worms in refuge (‘in refugia’) by not exposing large proportions of your farm’s worm population to drenches at the same time. Drenching and immediately moving your sheep to cereal stubble, for example, is a ‘good’ way of having few worms in refugia: this gives very good worm control but at the expense of strong selection for drench resistance.

Follow the best program for your area: see ‘Your Program’ in Wormboss.com.au.

Also regularly monitor worm burdens using worm egg counts (WormTest) and keep tabs on drench efficacy by doing DrenchChecks from time to time: a WormTest 10 days after drenching, in the case of sheep.

For high quality but easy to read information on all the strategies mentioned, go to WormBoss.com.au. It’s an indispensable resource for all who want to optimise sheep worm management.

It would be all too easy to blame the goat industry and this producer in particular for this first Australian case of MPL resistance. But consider this: resistance was discovered on this farm because the owner does regular WormTesting to monitor worm burdens and to check drench efficacy. These are two of the hallmarks of best practice worm management, the sort of things only done by the top 5-10% of sheep and goat producers.

Others may have missed, ignored, or covered up the problem. This owner however immediately sought professional assistance, not only for his own sake, but with the welfare of the industry in mind as well.

Perhaps, then, the sheep and goat industries have an earlier warning than they otherwise might have had: take advantage of this by improving how we do worm control.