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.
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.
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
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
wormmail in the cloud 