WRML.2017-07-28.wormfax.outlook. drench-right price.dung beetles.dawbuts. farming communications platform.cwd.meat will kill you?

In this issue

Wormfax for June
Outlook from the outhouse
Drenching at the right price
BOM outlook: August-October
Dawbuts Newsletter
Cattle endoparasiticides and dung beetles etc
Farms’ digital toolbox arrives
Chronic Wasting Disease (CWD)
What the health (Netflix) – Eating meat will kill you?
xkcd

Wormfax for June

WormFax for June has been added to the DPI website:

Outlook from the outhouse

Some things to ponder..

We keep saying this, but just because the lifecycle of many – especially cold sensitive worm species (barber’s pole worm (Haemonchus contortus), liver fluke (Fasciola hepatica)) – grind to a halt in winter in colder areas – it doesn’t mean you won’t have worm problems. And this is especially the case if you are unwittingly using ineffective drenches (a very real possibility).

The infective stages of barber’s pole worm (3rd stage larvae (L3)) and liver fluke (metacercariae aka ‘infective cysts’) produced in autumn will survive frosty conditions in winter, even though numbers decline steadily as winter goes on. (It’s the eggs that are cold sensitive for certain worm species; not so much the infective larval stages that the eggs produce).

So, if you treated for barber’s pole – or other roundworms – or liver fluke – in autumn, a mid-winter test would be a good idea to make sure the wheels are not about to fall off.

August is just around the corner, and some flukey properties will need a fluke drench then. Some farms can get away with a flukicide in early winter (April/May), the single most important fluke drench, but others will need a second drench in late winter/early Spring (Aug-Sept). Properties badly affected by fluke will need a summer treatment as well.

Remember drench resistance is happening in liver fluke, as well as roundworms of sheep/goats,  and cattle (and horses).  Never assume any drench – even new ones – will be highly effective. At the very least, consider doing a test after treatment to check drenches are working. WormBoss of course has good info on ‘DrenchChecks’. And this DPI Primefact on liver fluke discusses resistance in liver fluke, the tests available,  and how to check flukicide efficacy.

Australian sheep and goat producers should regularly consult Your Program in WormBoss. (There is a ‘Your Program’ tailored for different regions of Australia). If  you had just one ‘go to’ resource or document on worm control in sheep/goats, ‘Your Program’ is it.

By the way, WormBoss should have info on cattle worm control, in the next year or two. In the meantime, have you checked out MLAs’ Cattle Parasite Atlas, or DPI’s Primefact on cattle worms?

Speaking of cattle, most cattle in the higher rainfall areas of NSW (say the eastern third of the state) that were weaned in late autumn (say May, at around 8 months of age), would have required an effective(!) broad-spectrum drench at weaning (and a fluke drench as well, if needed). Most of the ‘worm impacts’ on grazing beef cattle in NSW are in the first 3-6 months after weaning.

On some farms, just the weaning drench will suffice. On other properties, with more worm problems (e.g. high rainfall; cattle-only properties), an additional one or two extra drenches – spaced roughly 3 months apart – may be needed. But, it is impossible to produce a one-size-fits all recipe for this, especially as worm egg counts in cattle after weaning age do not give as good a guide to actual worm burdens compared to the case in small ruminants. Producers who actually know the growth rates of their weaner cattle will have a better grasp of worm (and nutritional) impacts on their weaners, and whether they need to drench more (or can drench less).

Other variables include grazing management and whether long- or short-acting drenches are used. As to grazing management, preparing low worm-risk paddocks for weaner cattle will have a big impact on worm control and productivity.

And yes, resistance of cattle worms to drenches is an issue too, and very likely many producers are inadvertently using ineffective drenches.

If this year’s weaners are being kept into next year, for example, as replacement heifers, keep in mind ‘type 2 ostertagia disease’ (type 2 ostertagiosis). In NSW, when ‘type 2’ happens, it is often in late summer/autumn in cattle around 16-18 months of age.  The condition occurs as a result of  (cold conditioned??) Ostertagia infective larvae picked up in late winter/spring which enter the 4th stomach and go into ‘hibernation’ (hypobiosis) in the gastric glands, then resume development en masse (causing much damage to the abomasum) 3-6 months later.

Most people have forgotten about ‘type 2 ostertagiosis’, because it became less common in Australia with the advent of the macrocyclic lactone (ML) drenches from the 1980s onwards. But, once seen, never forgotten!: the weight loss and scouring (diarrhoea) can be very dramatic!

MLs are the ‘bee’s knees’ when it comes to killing adult and inhibited Ostertagia in cattle. Unless the Ostertagia are drench resistant. Yes, there are now reports of ML-resistant Ostertagia in cattle, in Australia, and elsewhere (see Waghorn and others, 2016), although currently ML resistance is seen more commonly in Cooperia (intestinal worm). See the last issue of WormMail for a recent NZ report (Waghorn and others, 2016) of ML-resistant Ostertagia ostertagi in cattle.

An effective drench in mid-late Spring should somewhat reduce the chances of type 2 ostertagiosis happening in yearlings a few months later.

Drenching at the right price

http://www.farmingahead.com.au/livestock/sheep/drenching-at-the-right-price/

BOM outlook: August-October

  • Below-average rainfall likely for most of southern mainland Australia
  • Days and nights likely to be warmer than average; highest likelihood in northern and southeastern Australia

http://www.bom.gov.au/climate/outlooks/#/overview/summary

Dawbuts Newsletter

 Another newsletter you might be interested in:  https://www.dawbuts.com/
Why ‘Dawbuts’:  Dr Matt Playford (Dawbuts principal) has strong Japanese connections and ‘dawbut’ sounds like the Japanese word for animal. (動物  dōbutsu).
[Disclaimer: no kickbacks from Dawbuts; zero conflicts of interest; I am paid by taxpayers; and I pay taxes  🙂 – Ed.]

Cattle endoparasiticides and dung beetles etc

S.A. Beynon, M. Peck, D.J. Mann, O.T. Lewis, 2012. Consequences of alternative and conventional endoparasite control in cattle for dung-associated invertebrates and ecosystem functioning. Agriculture, Ecosystems and Environment 162 (2012) 36– 44.
Abstract
Invertebrates associated with livestock dung provide a valuable ecosystem service of dung decomposition, but can be affected negatively by the use of livestock parasite-control products (anthelmintics). Alternative products are promoted as environmentally sustainable, but effects on dung fauna and dung processing have not yet been investigated. We assessed the effects of one conventional product (ivermectin) and three alternatives (a homoeopathic product, Bug A Tub (a free-choice lick containing <5% diatomaceous earth, plant oils and nutritional supplements) and a copper bolus), on dung fauna and decomposition. Bug A Tub reduced the attractiveness of dung, the abundance of dung-associated insects in the soil beneath pats, emergent insect biomass and dung beetle (Coleoptera: Scarabaeidae) emergence. Ivermectin dramatically altered insect assemblages, reducing emergent fly biomass. Ivermectin also reduced emergent dung beetle abundance. Dung from ivermectin-treated cattle had a significantly lower rate of decomposition, similar to when invertebrates were excluded, but none of the alternative products affected decomposition. Insect emergence varied widely for dung collected from cattle grazing different fields, highlighting the need to ensure experimental products are not confounded with dung source. Dung from ivermectin-treated cattle can act as an ecological trap (a poor-quality environment which associated invertebrates are forced to colonise) with potentially major consequences for the ecosystem service of dung decomposition. Bug A Tub can affect insects colonising dung, highlighting a need for tests on the environmental safety of alternative products; such testing is not currently a legal requirement.   (Obviously this is just part of the dung beetle etc story…as always, ‘trust but verify’ )

Farms’ digital toolbox arrives

27 Jul 2017, 6 a.m.

Excerpt:

GROUNDBREAKING collaboration by the Primary Industries Department, global technology giant Cisco and Molong farmer Ben Watts has delivered a farming communications platform without reliance on Australia’s telecos.

Cameras monitoring paddocks, sensors delivering hourly packets of information from remote locations and mobile weighing stations are just some of the applications already operating on Waidup Homestead, Molong.

The Orange Agricultural Institute, a DPI research headquarters, is also running the platform, but the gear was made farm tough on Mr Watts property.

(Image in article: Molong farmer Ben Watts, Cisco chief technology officer Kevin Bloch and Primary Industries Department deputy director general Michael Bullen).

Chronic Wasting Disease (CWD) – cervids

From a Canadian government website: http://www.inspection.gc.ca/animals/terrestrial-animals/diseases/reportable/cwd/fact-sheet/eng/1330189947852/1330190096558

Excerpt:

Chronic wasting disease (CWD) is a progressive, fatal nervous system disease known to naturally infect white-tailed deer, mule deer, moose, elk and reindeer.

What the health (Netflix) – Eating meat will kill you?

Here is one side of the argument (directed by Kip Andersen, Keegan Kuhn):  https://www.netflix.com/au/title/80174177
Here is another, by Nina Teicholz:
And here is another:

xkcd

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WRML.2017-07-13. WormTest results. ivermectin-resistant O ostertagi-cattle. von Ostertag.post-doc position-NZ. etc

In this issue:

Sheep WormTests in June (NSW)
Confirmation of ivermectin resistance in Ostertagia ostertagi in cattle in New Zealand-Waghorn et al
Robert von Ostertag etc – What’s in a name…?
Post-doctoral opportunity – AgResearch, New Zealand – parasitology, farmed deer
Occurrence, Measurement and Clinical Perspectives of Drug Resistance in Important Parasitic Helminths of Livestock-Woodgate et al
CliMate V2 (web-version) released Friday July 7, 2017
World-first pedigree sheep and cattle tag on-farm next month
Predictive sheep health app ASKBILL is music to Rhonda’s ears
Four of the most lethal infectious diseases of our time
Macleay recalls its greatest flood disaster-July 1949
xkcd

Sheep WormTests in June (NSW)

All the data (de-identified summaries) should be up on the web soon-ish (DPI website-WormFax). Contributing labs: Invetus (formerly VHR)-Armidale and  NSW DPI’s State Vet Diagnostic Lab.

I was just eyeballing some of the results (from Invetus, Armidale) for June.  Roughly 10% of the WormTests for Armidale had mean egg counts >1000. As a rule of thumb, the highest egg counts in a Worm Test are often 3-4 times the mean. Most of these were mainly Haemonchus. The highest mean was ~ 3000, with the highest individual count being ~10 000 epg. And this is winter.

Over in Dubbo, there was a mob (ewes/lambs) with a mean of ~ 2200, highest, 9400. (Mostly Haemonchus). In Northern New England, there was a mob with a mean epg of ~ 2200, highest ~ 9000.

And how about Yass? A mob of weaners there had a mean epg of ~ 2400, highest 12,000 (all Haemonchus).

So, why some high-ish Haemonchus counts even now, in winter?   A common response is that Haemonchus has changed, i.e., it has become more cold-adapted. Sure, this can and does occur, but most of the explanation is to be found elsewhere. (If you hear galloping (in AU), think ‘horses’ rather than ‘zebras’).

Once temps are consistently below 10 deg C overnight, and below 18 deg during the day, it is too cold for Haemonchus eggs to develop and hatch and, as they only live for ~ 5 days anyway, they have come to a dead-end. Maybe the eggs of cold-adapted strains can ‘do their thing’  two to a few ? degrees lower. Certainly when you get into regular frosts, or near to it, there won’t be any new Haemonchus larvae appearing on pasture.

But the 3rd stage larvae (infective larvae) produced in autumn, when conditions were kinder, are a different kettle of fish. They will survive over winter and into spring, albeit in declining numbers.

So, regarding these sheep above, from areas with cold winters, and which have decent Haemonchus egg counts: where did their worms come from?   They either picked up autumn-‘born’ larvae off pasture, and / or they are carrying existing burdens from summer/autumn.

There are no magic bullets, but the practical solutions – tried and tested – are known: it’s all in WormBoss. Start by checking out Your Program.

Confirmation of ivermectin resistance in Ostertagia ostertagi in cattle in New Zealand

Authors: Waghorn TS, Miller C and Leathwick DM, 2016. Veterinary Parasitology 229 (2016) 139–143.  Authors from: AgResearch Grasslands, Palmerston North 4442, New Zealand.

Excerpts:
Six suspected cases of ivermectin resistance in Ostertagia spp. in cattle were investigated after routine anthelmintic efficacy testing on commercial farms.

Isolates of Ostertagia spp. recovered from three of the farms were each used to infect 18 six month old calves. The efficacy of oral formulations of ivermectin and moxidectin, both at 0.2 mg/kg, was determined against each isolate by slaughter and worm count.

The efficacy of (oral) ivermectin (0.2mg/kg) against Ostertagia spp., based on differentiated FECRT for each of the farms varied from 0% to 88%. The efficacy of ivermectin based on worm counts in the slaughter trial varied from 13% to 75% but (oral) moxidectin (0.2mg/kg) was >99% effective against all isolates.

Albendazole, at a dose rate of 10 mg/kg (oral), failed to achieve 95% efficacy (faecal egg count reduction) against Ostertagia spp. on two farms (82% and 85%). Levamisole consistently failed to achieve 95% efficacy against Ostertagia spp. which is consistent with its known lesser efficacy against this parasite.

Authors further conclude: These results confirm the presence of macrocyclic lactone resistant O. ostertagi in cattle in New Zealand and the likely presence of dual resistance, to macrocyclic lactones and albendazole, in some isolates.
Resistant populations of this highly pathogenic parasite are probably not uncommon in New Zealand and pose a significant threat to animal production and welfare in the future.

They further state: Until recently, reports of resistance in the highly pathogenic Ostertagia ostertagi (Herlich, 1959) have been rare (Sutherland and Leathwick, 2011). However, cases have now been documented in the United States of America (Edmonds et al., 2010), Europe (Demeler et al., 2009; Geurden et al., 2015) and Australia (Rendell, 2010) and resistance is suspected to be developing in Argentina (Suarez and Cristel, 2007). In New Zealand, there have been anecdotal reports, and a number of anomalies in efficacy tests (Mason and McKay, 2006; Waghorn et al., 2006; McAnulty and Gibbs, 2010), which might have indicated emerging ML resistance in this parasite. To date (2016), however, none of these suspect cases have been confirmed (by worm counts and egg counts -Ed) as involving resistant parasites.  (Emphases mine – Ed.)

Robert von Ostertag etc – What’s in a name…?

· Ostertagia –after German veterinarian, Robert von Ostertag

· Salmonella – after USDA veterinarian, Daniel E Salmon (not Daniel Salmon, former Local Land Services veterinarian at Deniliquin, NSW).

· Brucella – after Bendigo-born Scottish pathologist and microbiologist Major-General Sir David Bruce who investigated Malta fever (B melitensis) in British soldiers.

· Johnes disease – after Heinrich A. Johne, a German bacteriologist and veterinarian.

(From https://wormmailinthecloud.wordpress.com/2014/11/24/wrml-2014-11-24-triclabendazole-resistant-liver-fluke-in-new-england-nsw-etc/)

Post-doctoral opportunity – AgResearch, New Zealand – parasitology, farmed deer

“..The objective of this Fixed-Term position is to establish the seasonal biology of lungworm and Ostertagia infection in young and adult red deer.  The job holder will be based at AgResearch Grasslands under the guidance of Dr David Leathwick ..”

More information:

Leathwick 2017-07-11 Post-doc job description AgRsearch Parasitology farmed deer

Occurrence, Measurement and Clinical Perspectives of Drug Resistance in Important Parasitic Helminths of Livestock

Woodgate RG, Cornell AJ and Sangster N, 2017. Occurrence, Measurement and Clinical Perspectives of Drug Resistance in Important Parasitic Helminths of Livestock. Chapter in book: Antimicrobial Drug Resistance, pp.1305-1326 (Vol 2 of 2). January 2017.DOI: 10.1007/978-3-319-47266-9_30  https://www.springer.com/la/book/9783319472645   ISBN 978-3-319-47266-9   Available also as an e-book and individual chapters can be purchased separately (~ $29.95).

Abstract
Livestock parasite resistance to anthelmintics remains one of the major limitations to ongoing animal health, welfare and productivity worldwide. Subsequent less-than-optimal parasite control can impose significant direct and indirect costs within all production and recreation livestock enterprises. This chapter briefly summarises the biology and epidemiology of the important nematode and trematode parasites of cattle, sheep and horses around the world. Then it details the application, including modes of action and specific mechanisms of resistance, of the key anthelmintic options to assist their control. The general principles regarding the development of anthelmintic resistance are discussed in light of an understanding to assist the slowing of worsening spread and to support effective and sustainable helminth control. There is also discussion of methods to detect, measure and monitor anthelmintic resistance.

CliMate V2 (web-version) released Friday July 7, 2017

CliMate (v2), with 10 analyses, facilitates exploration of climate records to ask questions relating to rainfall, temperature, radiation, and derived variables such as heat sums, soil water and soil nitrate accumulation. It is designed for decision makers whose business relies on the weather, who want to better quantify risk and system status.

Visit climateapp.net.au to use the new version.   (And it’s a secure connection (HTTPS) to the site (as opposed to HTTP)).

World-first pedigree sheep and cattle tag on-farm next month

By Terry Sim, 07 July 2017

A WORLD-FIRST maternal pedigree collection tag system suitable for sheep, cattle and goats will have its final production-proofing trial in a New South Wales sheep flock next month.

https://www.sheepcentral.com/world-first-pedigree-sheep-and-cattle-tag-on-farm-next-month/

Predictive sheep health app ASKBILL is music to Rhonda’s ears

By Sheep Central, 10 July 2017

THE sheep industry’s new predictive app ASKBILL now has its own song thanks to the song-writing skills of Sheep CRC office manager Rhonda Brooks.

https://www.sheepcentral.com/predictive-sheep-health-app-askbill-is-music-to-rhondas-ears/

But, is the AskBill song as good as the WormBoss song from ~ 2005?? (Lyrics and lead singer: Arthur Le Feuvre, first/founding leader of the WormBoss team. (WormBoss: the first of the Bosses) Rhonda’s pretty good, Artie: have you met your match??) – Ed.

Rapid sheep flock increase unlikely despite productivity gains

By Terry Sim, 12 July 2017

MARKET and flock dynamics mean Australia’s sheep and lamb numbers are unlikely to increase rapidly, despite productivity gains indicated in the latest Agricultural Census data.

https://www.sheepcentral.com/sheep-numbers-unlikely-to-lift-quickly-despite-productivity-improvements/

According to the Australian Bureau of Statistics’ last Agricultural Census (2015-2016), the national flock decreased by 3% compared to the flock size of ~68 million recorded in the 2010-2011 census. But there is more to this story, according to NSW DPI’s Phil Graham and others…   Ed.

Four of the most lethal infectious diseases of our time

https://theconversation.com/four-of-the-most-lethal-infectious-diseases-of-our-time-and-how-were-overcoming-them-78101

Interesting article. (Thanks KQ).

Macleay recalls its greatest flood disaster-July 1949

12 Jul 2017, 3 p.m. The Land.  http://www.theland.com.au/story/4759483/when-the-rain-falls-in-july/?cs=4951

Interesting story and pictures. Some excerpts:

The great wash, with a ‘wall of water’ coursing down the catchment, drowned more than 15,000 head of cattle, killed six people and washed away 53 homes and businesses, with scores more wrecked … Almost a metre of rain fell into the great valley by late July –  a year’s precipitation in half the time …  There must have been a cold front as part of this storm as it snowed so much at Walcha and Guyra that drifts covered the guideposts. 

4th of July (USA) – xkcd

https://xkcd.com/1858/

WRML.2017-07-06.spring lambing-worm control.temperature-herbicides and drenches.genetics of resistance.FAMACHA.variability in dose and resistance. etc

In this issue:

Spring lambing and worms
Weed resistance may be a matter of temperature – what does this have to do with worms??!!
Genomic introgression mapping of field-derived multiple-anthelmintic resistance in Teladorsagia circumcincta – Choi Y-J et al
Managing anthelmintic resistance—Variability in the dose of drug reaching the target worms influences selection for resistance? – Leathwick et al
Validation of the FAMACHA© system in South American camelids – Storey et al
Enabling change in rural and regional Australia: The role of extension….Vanclay and Leech 2006
Chlamydia in sheep ‘highly prevalent’ and not transmitted how you might think
Psittacosis believed to be transmitted from horses to humans at Charles Sturt University Wagga
ABC pictures of the week
Dr Who cliffhanger and the Christmas Special
xkcd

Spring lambing and worms

Pareto and parasites

From Better Explained:  Originally, the Pareto Principle referred to the observation that 80% of Italy’s wealth belonged to only 20% of the population. More generally, the Pareto Principle is the observation (not law) that most things in life are not distributed evenly.

And so it is with worms. Most of the worms in a mob of sheep tend to come from a minority of animals. As to classes of sheep, a disproportionate number of worms are to be found in young sheep and lambing/lactating ewes.

Hence the importance of good worm control in ewes from late pregnancy through to weaning, which has flow on effects to the lambs, in addition to direct treatment of lambs, usually at weaning. Check Your Program at WormBoss.

Grazing management

Grazing management is about preparing low worm-risk paddocks for vulnerable livestock, notably, lambing ewes, and weaners. This is not as hard as you think and does not necessarily mean ‘no grazing at all by sheep (or goats)’ during preparation time. But planning is required. Again, see Your Program, and also the section on Grazing Management in W-Boss. It’s not just about worms however: nutrition and agronomic concerns are important too!

It’s too late baby..

But, in the main sheep areas of NSW (eastern half of the state), preparing a low worm-risk paddock for Spring takes 5-6 months, according to what your location. (Again, see Your Program).

Drenching before lambing

Often ewes require drenching before lambing. It may be a routine/regular drench in your area, according to Your Program (e.g., the Haemonchus-endemic summer rainfall zone of northeastern NSW), or Your Program suggests a worm egg count beforehand to determine the need.

If you drench, almost certainly a broadspectrum drench will be required, but it has to be effective on your farm. This requires on-going monitoring of drench efficacy, for example by regular DrenchChecks. Time and money well spent!

Long- or short-acting drench?

This is one of the three principles in WormBoss regarding slowing down development of resistance:  ‘Use short-acting treatments and restrict the use of persistent products for specific purposes and high worm-risk times of year’.

If you use a long-acting drench, you must, as with any drench, know beforehand that it will work. There is less need for long-acting drenches if grazing management is done well and drenches, when used, are effective.

What are long-acting products? “Effective persistent treatments kill immature and adult worms at the time of treatment, as well as infective larvae eaten by animals (with pasture) during the period of protection of the treatment—for sheep, this is about 3 months for long-acting and 1–6 weeks for mid-length treatments (depending on the particular product).” (More here)

Also, for long-acting products, WormBoss says this:  ‘Use primer and exit drenches with long-acting treatments’. Maybe 10-20 years ago, when resistance was less prevalent, you could (seemingly) get away without doing this.

Wormboss continues:

“Primer drenches clear the animal of any worms that are resistant to the long-acting treatment. A primer drench is an effective short-acting drench (preferably a combination) that does not include the same group as the long-acting product. Give a primer at the same time that a long-acting product is given.”

“Exit drenches are used two weeks after the end of the actual protection period. By this time the persistent treatment has declined to very low levels. The exit drench kills larvae that have survived the persistent treatment and developed into breeding adult worms. Another name for the exit drench is a ‘tail cutter’.”

“An exit drench (like the primer drench) is an effective short-acting treatment (preferably a combination) that is from a different group/s to the persistent product.”

An exit drench (following a long-acting product given pre-lambing) may well be the drench you give to ewes at weaning when they leave the lambing paddock, assuming weaning is about 12-14 weeks from the start of lambing.

Making sure the long-acting product is working: ” it is best to check the effectiveness of long-acting products every year they are used by doing a WormTest at 30 and 60 days.”  You might also consider one 14 days after the product is administered, especially if you did not give a primer ( or you don’t really know the primer was highly effective and/or you don’t know for sure the long-acting product will be effective). More here.

Make sure animals leaving the lambing paddock are cleaned  out with an effective drench unrelated to the drench active(s) given pre-lambing.

Essential, cost-effective tools: if you are not investing in regular Worm Tests and DrenchChecks, you are making life harder for yourself (and easier for profit-eating worms).

Oh, and follow the label. For example, the label may prohibit re-use of a drench within a certain interval, for example, 270 days in the case of at least two long-acting products, and 91 days in the case of another.

Weed resistance may be a matter of temperature – what does this have to do with worms??!!

Source: http://www.farmingahead.com.au/cropping/chemicals/weed-resistance-may-be-a-matter-of-temperature/

So what do weeds have to do with worms of livestock, or flukicides.

From the article above:  “ACCORDING to associate professor Chris Preston from Weed Management at the University of Adelaide, herbicides applied under the wrong temperature conditions can appear to fail, however the reason may not be herbicide resistance.”   “Dr Preston said most herbicides have an optimal temperature range at which they are most effective in controlling target weeds.”    ” ‘Combining the optimal temperature with optimal weed size will give the best results possible’.”   ““The current common practice of applying clethodim to tillered ryegrass in the coldest months is not making the best use of this herbicide.”     According to Dr Preston, as a general rule of thumb, Group A (fops), paraquat (Group L) and glyphosate (Group M) are more effective at lower temperatures while Group A (dims), atrazine (Group C) and glufosinate (Group N) are more effective at higher temperatures.”

Well, this apparently temperature related effect reminds me of an interesting paper by Sargent and others (Aust Vet J; 2009). More detail can be found here. Of course the best option is to read the paper for yourself.

The efficacy of two pour-on (topical) triclabendazole-based flukicides, each applied at different times of the year (winter, spring, summer), were compared. One product was from the company for whom Sargent worked; the other was from a competitor. The differences between the two products were not statistically significant. The results are summarized in the graph below:

Genomic introgression mapping of field-derived multiple-anthelmintic resistance in Teladorsagia circumcincta

Choi Y-J, Bisset SA, Doyle SR, Hallsworth-Pepin K, Martin J, Grant WN, et al. (2017) Genomic introgression mapping of field-derived multiple-anthelmintic resistance in Teladorsagia circumcincta. PLoS Genet 13(6): e1006857. https://doi.org/10.1371/journal.pgen.1006857   (Open access).

PLoS Genet. 2017 Jun 23;13(6):e1006857. doi: 10.1371/journal.pgen.1006857. [Epub ahead of print]
Abstract
Preventive chemotherapy has long been practiced against nematode parasites of livestock, leading to widespread drug resistance, and is increasingly being adopted for eradication of human parasitic nematodes even though it is similarly likely to lead to drug resistance. Given that the genetic architecture of resistance is poorly understood for any nematode, we have analyzed multidrug resistant Teladorsagia circumcincta, a major parasite of sheep, as a model for analysis of resistance selection. We introgressed a field-derived multiresistant genotype into a partially inbred susceptible genetic background (through repeated backcrossing and drug selection) and performed genome-wide scans in the backcross progeny and drug-selected F2 populations to identify the major genes responsible for the multidrug resistance. We identified variation linking candidate resistance genes to each drug class. Putative mechanisms included target site polymorphism, changes in likely regulatory regions and copy number variation in efflux transporters. This work elucidates the genetic architecture of multiple anthelmintic resistance in a parasitic nematode for the first time and establishes a framework for future studies of anthelmintic resistance in nematode parasites of humans.
PMID: 28644839 DOI: 10.1371/journal.pgen.1006857

Author summary

Teladorsagia circumcincta is an economically significant nematode (roundworm) pathogen affecting sheep and goats in temperate regions of the world. The widespread use of prophylactic treatment has resulted in rapid selection for anthelmintic (anti-worm drug) resistance in this and other species of livestock parasites. The mechanism of resistance is not well understood because most studies have focused on the role of candidate genes using simplistic models of single gene selection, despite evidence that the evolution of resistance is more complex. Here, we report on a comprehensive whole-genome analysis that elucidated resistance-associated genes, which was facilitated by developing a pair of T. circumcincta strains sharing a largely common genetic background but differing markedly in their susceptibility to anthelmintic drugs. The results show that multiple genetic factors contribute to anthelmintic resistance in a variety of ways, including possible reduction/modulation in target site sensitivity, reduced target site expression, and increased drug efflux, to name a few. This suggests that drug resistance in these parasites is a multifactorial quantitative trait rather than a simple discrete Mendelian character. With this study, we established a genomics-based experimental paradigm for investigating anthelmintic resistance, at a time when its medical importance is rapidly increasing   (Emphasis mine-Ed.)

Managing anthelmintic resistance—Variability in the dose of drug reaching the target worms influences selection for resistance?

Dave M. Leathwick, Dongwen Luo, 2017. Veterinary Parasitology 243 (2017) 29–35.  http://www.sciencedirect.com/science/journal/03044017

The highlights:

  • The effect of variation in drug dose reaching the target worms was investigated;
  • Monte-Carlo simulation was used;
  • resistance was selected more by a lower mean and higher variability of dose;
  • route of administration may be important in selecting for drug resistance.

As always, check out the paper for yourself.

Validation of the FAMACHA© system in South American camelids

Bobby E Storey, Lisa H. Williamson,Sue B. Howell,Thomas H. Terrill, Roy Berghaus, Anand N. Vidyashankar, Ray M. Kaplan, 2017. Veterinary Parasitology.

https://doi.org/10.1016/j.vetpar.2017.06.004

Read the paper for yourself but the highlights were reported as follows: there were statistically significant correlations between packed cell volume (PCV) and FAMACHA© score; FAMACHA© score and Fecal Egg Count (FEC); body condition score (BCS) and FEC for Haemonchus contortus;  and BCS and FEC for Trichostrongylus spp. It was concluded that the FAMACHA© system is applicable to South American Camelids.

Enabling change in rural and regional Australia: The role of extension….Vanclay and Leech 2006

https://www.researchgate.net/publication/265132106_Enabling_change_in_rural_and_regional_Australia_The_role_of_extension_in_achieving_sustainable_and_productive_futures_A_discussion_document_produced_by_the_State_Extension_Leaders_Network

Chlamydia in sheep ‘highly prevalent’ and not transmitted how you might think

Source: The Land / Amy Mitchell-Whittington 5 Jul 2017, 9:15 a.m.

http://www.theland.com.au/story/4771787/chlamydia-in-sheep-highly-prevalent-and-not-transmitted-how-you-might-think/?cs=4951

Psittacosis believed to be transmitted from horses to humans at Charles Sturt University Wagga

Source: The Land / Madeleine Clarke4 Jul 2017, 10 a.m.  http://www.theland.com.au/story/4768807/horse-disease-infects-humans-in-wagga/?cs=4951

“Staff and students at Wagga’s Charles Sturt University (CSU) have fallen ill after exposure to “horse chlamydia” on two separate occasions.

The worrying transmission of the illness “psittacosis”, which causes flu-like symptoms in humans, is believed to be a world-first.”

ABC pictures of the week

http://www.abc.net.au/news/2017-06-30/abc-open-pic-of-the-week/8664982

Dr Who cliffhanger and the Christmas Special

http://www.radiotimes.com/news/2017-07-01/what-does-that-doctor-who-cliffhanger-mean-for-the-christmas-special

 

xkcd

SL, Armidale. 2017-07-06