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In this WRML: reduced efficacy of monepantel in goats [NZ]. Sheep Husbandry Practices Guide [MLA]. NEMSE Field Day. Getting screwed. VetGun parasiticide delivery system. engineering accurate dosing. cloaca.
Reduced efficacy of monepantel in goats on a farm in NZ
At a conference in NZ in January this year, Scott and others reported a case of reduced efficacy of monepantel (‘Zolvix’ (Novartis)) on a NZ goat farm.
From the abstract:
* Early 2012: parasitic gastroenteritis on a property in goats despite recent treatment with monepantel (MPL; ‘Zolvix’ (Novartis)).
* History of resistance on farm to ‘all three traditional drench families’. (Presumably this means the benzimidazoles (BZs), levamisole (LEV) and macrocyclic lactones (MLs). I understand the farm, a small hobby farm, had a history of failure of triple drenches (e.g. BZ+LEV+ML).
* ‘Had been using MPL for ~ 2 years at 1.5x the sheep dose rate, (although it is unclear to me if this dose rate was used from day one or not. Certainly some goat owners in Australia used MPL at the sheep dose rate when it first came out. Apart from being an off-label usage (not registered for use in goats at any dose rate) , this does not augur well for the longevity of the product).
* Faecal egg count reduction test (FECRT) : 12 mixed age goats treated with MPL, 12 at 1.5x, and 4 at 3x the sheep dose rate (3.75 and 7.5 mg/kg respectively). Re-sampled 8 days after treatment.
* FECRT: no reduction in egg count with either MPL treatments.
* Also, 12 nine month old lambs were grazed on the goat farm for 5 weeks, then brought indoors for 2 weeks, then treated with MPL (average dose: 2.9 mg/kg).
* The 12 lambs were slaughtered 9 days post-treatment: worm counts showed MPL had ‘reduced or inapparent efficacy against more than one nematode species’. ( I guess ‘inapparent’ means zero or close to it).
The abstract gives no details on what species/genera of worms were present, frequency of treatment with MPL during the two year period, other worm management practices etc. (It is only an abstract after all).
However, those present at the conference in January tell me that Trichostrongylus colubriformis (black scour worm) and Teladorsagia circumcincta(small brown stomach worm) were the species involved and that monepantel was used on 17 consecutive occasions (no other drenches were used) on this farm, a 3Ha hobby farm , which had approximately 20 breeding goats and a very small number of sheep and cattle.
The authors do not declare that resistance has been diagnosed (possibly because Zolvix has no registered label claims for worms in goats?).
Reference: Scott I, Pomroy WE, Kenyon P, Smith G, Adlington B, and Moss A. Efficacy of monepantel against goat-derived parasite strains: the results of an egg count reduction test in goats and a slaughter study in sheep. International Sheep Veterinary Congress, New Zealand, 2013.
No doubt a full, more comprehensive paper has been submitted for publication in a peer-reviewed journal. (Awaited with interest).
With some exceptions, it seems to take about 5 years, in Australia at least, before we get the first published report of resistance of sheep /goat worms to a new anthelmintic. See Love S (2011), Table, page 4,5)). [ http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0009/111060/Drench-resistance-and-sheep-worm-control.pdf
Unfortunately MPL seems to be roughly on schedule, in goats at least.
Goat and sheep owners optimally should have a good program of integrated worm management including but not limited to using combinations of unrelated drench actives (best), or rotating between unrelated drench actives known (by testing) to be effective on a given farm. For more on IPM, see WormBoss. e.g. http://www.wormboss.com.au/tests-tools/management-tools.php
For information on combinations see, for example : http://www.wormboss.com.au/tests-tools/management-tools/drench-mixtures-and-combinations.php
So, if I were a goat owner….?
Well, firstly I would have the advantage of being a vet and thus being able to prescribe off-label, and also having the advantage of an off-farm income (for the time being at least).
Goat owners, in Australia at least, face the extra challenge of having a very limited selection of drenches registered for use in goats. On the other hand, pharmaceutical companies understandably do not like to see their drenches used off-label in goats: resistance occurs fast enough when drenches registered for sheep are used in sheep; resistance seems to happen even faster when sheep drenches are used off-label in goats. (‘Off-label’ means used contrary to label directions).
The reality is, we know, rightly or wrongly, that goat owners will use sheep drenches. They are in a bind.
Using sheep drenches off-label (i.e. in goats) doesn’t do away with all the issues: you have to work out the right dose for goats (often but not always about twice the dose rate for sheep, and being mindful of safety as well as efficacy)), then you have to deal with withholding periods, especially in products for which no maximum residue level has been set for goats. (I am talking about the regulatory landscape in NSW here).
So, pretending the above are not issues, and that cost is not an issue, I would tell myself as a goat owner to NEVER use ‘Zolvix’ on its own from day one (if I was determined to use Zolvix), or other drench actives on their own, for as long as possible. This is with the aim of slowing the development resistance of worms to MPL and other actives.
Even limiting oneself to registered drenches, goat owners in NSW could at the very least use ‘Caprimec’ (abamectin) and a BZ drench registered for use in goats, at the same time, on each and every occasion they drenched. One could use morantel (‘Oralject’) as well, which is another, unrelated broad-spectrum (levamisole-morantel group) registered for use in goats. (To find out about drench groups, see WormBoss).
So, there are three unrelated broad-spectrum drench actives available: abamectin, various BZs , and morantel. There was at one time a permit allowing for ‘Neguvon’ (trichlorfon, an organophosphate) usage (against Haemonchus) in goats in AU, but I believe that has expired and ‘Neguvon’ may no longer be available.
If I was going to use Zolvix, I would use it at 2 times the sheep dose rate, and I would drench with abamectin at the same time, i.e. up the race with ‘Zolvix’ and up the race again with abamectin. Even better, I would use a BZ as well, so effectively a three-way combination. Better, would be monepantel and three other unrelated actives.
Of course I would also have to think seriously about biosecurity i.e. not importing resistant worms, or other nasties. For information on the general principles of quarantine treatments, see : http://www.wormboss.com.au/news/articles/drenches/quarantine-drenching-getting-it-right.php
(You might need advice on the details. Using naphthalophos in goats for example could be problematic due to the relatively narrow safety margin (narrower than in sheep, according to work years ago by Cliff Hall).
Of course, it is so easy for me to say all this from my ivory tower, but I think I am making reasonable sense. Think about it anyway.
Goat owners in particular can’t afford to use Zolvix, or any other broad-spectrum drench, on its own. You also MUST know what drenches work on your property and keep tabs on them. See: http://www.wormboss.com.au/tests-tools.php
Further, the use of combination drenches is not a magic bullet: they need to be part of a good worm management plan.
‘Sheep Husbandry Practices Guide’ – MLA website
Dr Matt Playford has brought the new Sheep Husbandry Guide to my attention.
“I hope it may be of interest to your readers. This has been a long time in the making, now finally come to fruition. ” – Matt.
Publication title: A producers’ guide to sheep husbandry practices Publication code: 9781925045062
http://www.mla.com.au/News-and-resources/Publication-details?pubid=6106 or, you can try this: or use this preview TinyURL:
July WormBoss news
It should be out soon. Have you subscribed? www.wormboss.com.au
Here is the blurb I just wrote for it:
“We are coming up to Spring lambing in many parts of NSW. Of course it is too late to preach to you about the critical importance of lambing paddock preparation. There is good information on this in WormBoss of course. Type ‘lambing’ into the search box, and also read the ‘Your Program’ for you region. It is not onerous: it is brief and too the point (which I think may be a tautology, although I suppose you can brief but pointless).
Wormboss including ‘Your Program’ is great! (Have I mentioned that before?).
Depending on your region a pre-lambing drench may or may not be recommended as routine. Certainly you need to have a good program of WormTesting to see what worm burdens ewes are carrying before lambing, and what ewes and lambs are carrying between lambing and weaning. Again, WormBoss, including its Drench Decision Guides, has the answers.
If/when doing a pre-lambing drench, consider a DrenchCheck also. If the drench didn’t work well, you will ‘reap the whirlwind’ i.e. big worm problems for months downstream from lambing, in ewes and lambs, especially if you did not prepare low risk lambing paddocks.
We are also approaching August, an ‘A’ month. ‘A’ months are the two most important months to drench for liver fluke (sheep, cattle, goats, alpacas), with April being the most important. Some need to drench for fluke in April only (i.e. April-May, when the frosts start), some need to do an August drench as well, and some with very ‘flukey’ farms need one in February also. Consider rotating between unrelated flukicides (or using combination flukicides! e.g. Nitromec in cattle) on each occasion. Resistance is out there.
If you don’t know if you need to treat for liver fluke, test for liver fluke in April, August and February. Testing options include the liver fluke worm egg count, the liver fluke antibody ELISA (blood test), and the faecal fluke antigen test. All have their pros and cons. More information: Search for ‘liver fluke’ at WormBoss.com.au, check out the DPI wesbite (http://www.dpi.nsw.gov.au/agriculture/livestock/sheep/health ; http://www.dpi.nsw.gov.au/agriculture/vetmanual/specimens-by-discipline/parasitology/fasciola ) and go to the CSU Vet Lab (Wagga) page for information on the fluke faecal antigen test ( http://www.csu.edu.au/vetservices/vdl You may need to contact the lab for more information).
Remember that liver fluke infective larvae (metacercariae), unlike round worm larvae, occur in patches on a farm (where the intermediate host (snail) habitat is), so some mobs on a flukey farm could be negative on testing, depending on grazing and treatment histories.
Liver fluke is a zoonosis. There is more information here : http://www.dpi.nsw.gov.au/biosecurity/animal/humans/zoonoses-transmission as well as in the NSW DPI Primefacts/FactSheets on liver fluke.
-Stephen Love, Veterinarian/Parasitologist, NSW DPI, Armidale”
New England Merino Sire Evaluation Field day – organiser: Jim Meckiff, NSW DPI Armidale
For your information. RSVP is today! (19 July). email@example.com Tel: 0428 968 159
Getting screwed – a parasite story
‘Brought to my attention by my better half: http://www.abc.net.au/news/2013-07-18/maggots-lived-in-womans-ear-after-peru-trip/4827524
There was a case years ago of a woman travelling back to Australia who had a screw worm infested cut on her head. She sort medical advice (before and after arriving back in AU) but it was not definitively diagnosed until she happened upon someone connected with the former NSW DPI Vet Lab at Wagga Wagga.
VetGun (ecto-) parasiticide delivery system
‘Brought to my attention by a Kiwi colleague. Another colleague tells me that something like this has been used in South America for at least 6 years.
Of course this is ‘cool’, especially for ‘the boys’, but how well does it work and is it sustainable? (selection for resistance?). I don’t know.
“Australian veterinary equipment firm SmartVet has launched its parasiticide delivery VetGun system in the US.
The company claims the VetGun could change the landscape of parasite management in cattle. It said a rancher working alone can dose up to 100 cattle per hour using the technology.
SmartVet said the VetGun is the only dosing system not requiring animal handling, herding, yarding and running cattle through a chute. It allows dosing to take place in the field from a safe distance, thereby reducing stress and the chance of injuries to cattle and ranchers alike.
The company said the paintball-styled VetGun is a precision-engineered CO2-powered application device that delivers a new dosage form called a VetCap. The VetCap bursts on hitting the cow releasing its parasiticide contents.
“VetGun is so quick, simple and effective that one person working alone can treat an entire herd in the field, resulting in major savings of labor; time and money. Not only does it allow for convenient timing of insecticide application to deliver maximum parasite control, it also allows for precise dosage control,” said Randall Tosh, SmartVet’s vice president of business.
“It also reduces animal stress which in turn leads to improved feed conversion efficiencies, weight gain, overall health and productivity which add to the producers’ profitability. VetGun can even substantially contribute to alleviating horn fly resistance.”
The SmartVet US operation is based in Olathe, Kansas. SmartVet was co-founded by a fourth-generation cattle rancher and specializes in finding simple, logical solutions to everyday animal health challenges. The VetGun came after four years of research by the company (Source: Animal Pharm, June 18). ”
There is a video on http://www.smartvet.com/ .
An engineering solution – getting the right dose each time
When talking at a meeting at Cowra several weeks ago, someone in the meeting, commenting on the problem of inaccurate dosing, asked, ‘Why is an engineering solution always considered last?”
I think his point was: surely a system can be devised that weighs each animal and then calibrates the gun appropriately.
Something to think about.
Of course we all know what cloaca means, but I didn’t realise its original meaning was ‘outhouse’ or ‘sewer’.
There is always something new to learn in the world of parasitology and sewage.
The following is from Word.A.Day. (You can subscribe).
with Anu Garg http://wordsmith.org/awad/index.html
plural cloacae (klo-AY-se, -kee)
1. An outhouse.
2. A sewer.
3. The common duct into which intestinal, urinary, and genital tracts open in birds, reptiles, most fishes, and some mammals.
From Latin cloaca (sewer, canal), from cluere (to cleanse). Earliest documented use: 1656.
“David Walsh has found that cloaca happens. Having spent $180 million establishing Museum of Old and New Art, the most famous exhibit being Cloaca, a complicated poo-producing machine, Mr Walsh is now involved in a legal stoush* with the Australian Tax Office.”
MONA founder in Tax Office sights; The Sydney Morning Herald (Australia); Jun 7, 2012.
“Anne had balked at hanging her mistress’s most beautiful clothes in the cloaca … because of the smell.”
Posie Graeme-Evans; The Anne Trilogy; Atria; 2002.
So, what placental mammals have a true cloaca as adults? https://en.wikipedia.org/wiki/Cloaca (Queenslanders excluded.. 🙂
New England Merino Sire Evaluation Field Day 2013x.pdf