WRML.2016-07-28. notes on liver fluke. Dr Evelyn Walker wins award

In this issue:

  • Some notes on liver fluke – SL
  • Young Alumni Faculty Award for Outstanding Achievement – Dr Evelyn Walker
  • osis vs iasis – splitting hairs (but not infinitives)?
  • Ostertagiosis

Rough notes on liver fluke in grazing livestock – Australia

Someone recently asked me what I thought of various aspects of liver fluke (Fasciola hepatica), including impact on production.  This, basically, is the overview I gave them.

Pathogenicity: it’s up with that other important haematophagous worm, Haemonchus spp.

The difference is that Fasciola‘s distribution, limited by its intermediate host snail, is patchy, whereas Haemonchus is more uniformly distributed in sheep raising areas. Liver fluke is only present in some areas and, on affected properties, only occurs in some paddocks.

Being pathogenic, it has a significant economic impact on grazing livestock. Analyses of its economic impact have been done, for example, by Boray (NSW DPI PrimeFact on liver fluke), MLA-funded studies (Sackett et al 2006 and later (‘Priority list of endemic diseases…’)), and Lane (2015, cited by Woodgate et al 2016). Lane (2015) estimated the cost to the Australian sheep industry to be $25 million p.a. According to Hutchinson (2003), liver fluke has been estimated to result in 5% average loss of production and some $20 million annual costs of chemical treatments.

Effects: liver damage (parenchyma (the meaty part) and bile ducts), blood and protein loss, inappetance, and increased risk of black disease (Clostridium novyi), and sometimes deaths. Fluke-associated liver damage at abattoirs can result in condemned livers: another cost.

The following table is indicative of what losses may occur with different fluke burdens.

Table. Effects of Fasciola hepatica on weight gains in sheep. Adapted from Hawkins and Morris, 1978.

Group Fluke burden (fluke recovered) Total gain as % of controls
1 (Control) 0 100
2 45 95
3 67 70
4 117 78
5 230 63
6,7,8 346,1122,1755 respectively (Died)

Most common form of fasciolosis (in livestock grazed in SE Australia): chronic (with ill-thrift, anaemia, bottle-jaw, and perhaps jaundice). It occurs as a result of ingesting moderate numbers (200–500) of metacercariae over longer periods of time (Merck). Less common: peracute and subacute (from large numbers of migrating immature fluke), in which deaths happen more commonly.

Sheep do not appear to develop resistance to infection, and chronic liver damage is cumulative over several years. In cattle, a partial acquired resistance develops beginning 5–6 mo after infection (Merck).

Diagnostic tests: The traditional test is the liver fluke egg count. This is a sedimentation test (SEDI), unlike the egg count for nematodes, in which eggs are usually floated, usually in saturated salt (NaCl) solution (SG=1.2). Being more dense than roundworm eggs, fluke eggs sink in saturated NaCl solutions. They will float in sat. zinc sulphate solution (SG=1.36), but sedimentation is preferred as it is more accurate (Radostits and others, 2007)

Worm egg counts are not highly sensitive tests, i.e. there can be ‘a few’ false negatives, and the Fasciola egg count is no exception and may be worse than many. The sensitivity of the fluke egg count is often in the range of 30-70% (Woodgate et al, 2016), sometimes worse, sometimes better. The fluke antibody ELISA offered by NSW DPI is more sensitive and specific (~ 95-99% according to Hutchinson, 2003, cited by Woodgate et al, 2016), but there is a lag period from the time of infection until antibodies rise, then another lag period from when an infection is cleared (by an efficient flukicide) until the antibodies fall. These lag periods can be a few to several weeks or more.  There are no perfect diagnostic tests.

More recently a European ELISA-based kit (CAELISA (copro-antigen ELISA), Bio-X, Belgium) which measures fluke antigen (as opposed to antibody) in faeces has been validated by Charles Sturt University at Wagga Wagga. Palmer et al. (2014) calculated sensitivity to be between 75 and 91 per cent and specificity between 70 and 100 per cent. But this test is more expensive than SEDI. See Woodgate and others, 2016. Some operators (e.g. Palmer) improve sensitivity by customising the cut-off point in the test. I understand Bio-X has recently produced an improved version of the test.

According to Brockwell (2013), the copro-antigen test (CT) reportedly shows ‘moderate to good’ correlations with parasite burdens in cattle (R2 ranging from 0.239 to .871) (Brockwell et al 2013) and 0.899 in lambs (Mezo et al, 2014). Roblez-Peres et al (2013) found PCR to be more sensitive than the BIOX CT in detecting drug resistant fluke (and others found PCR and CT to be more sensitive than faecal fluke egg count (FEC), however the CT in that case was used at the BIOX recommended cut-off rather than a custom cut-off. Brockwell and others (2014) recovered live adult flukes at slaughter following triclabendazole (TCBZ) treatment of 6 cattle from 3 of the beef properties they studied, confirming the TCBZ resistance status of F. hepatica in these cattle. This showed the test positives were not false positives. The correlation between FEC and fluke number was R2 = 0.1801 and for coproantigen R2 = 0.3542, but note the small sample size.

Interpretation: What do fluke egg counts (SEDI) mean?  Even though liver flukes (which, by the way, are hermaphrodites) are more fecund than Haemonchus – fluke producing about twice as many eggs as Haemonchus – the fluke egg counts typically seen in labs are low.   The great majority in NSW at least are below 100 epg, with most being less than 50 epg, especially in the case of cattle. While fluke are more fecund, there are less of them.  The highest fluke egg count I have seen was 300-400 epg (Merino ewes set-stocked in a  creek paddock south of Walcha, NSW); and the highest I have heard of was ~ 1000 epg, and that was on irrigated pasture in the Riverina and with flukicide resistance. (The first report of triclabendazole-resistant fluke in the world came from a nearby region in northern Victoria (Overend and Bowen, 1995).

However, one liver fluke egg can result in – after the cycle progresses (asexual reproduction and multiplication) within the intermediate host snails – up to 4000 metacercariae (the infective stage/cyst on herbage).

A very heavy fluke burden – say 200+ worms in cattle and  600+ in sheep (according to old NSW DPI guidelines) – has about 10-20x fewer worms present than a very heavy Haemonchus burden in sheep. (I don’t really understand the differences in ‘very heavy fluke burdens’ for cattle (200+) vs sheep (600+) either…Here’s a thought: perhaps there is a greater cost –disease-and production-wise- per fluke to cattle because there is a stronger immune response???)). But, on the other hand, fluke are a bigger parasite, and also the immature stages, while small, can, in the early stages, do a lot of damage as the migrate through the parenchyma of the liver. Adult fluke can also live a long time (Adult flukes may live in the bile ducts of sheep for years; most are shed from cattle within 5–6 mo.(Merck)).

(By the way, alpacas, with their relatively small livers, are reputed to be very susceptible to fasciolosis (disease from fluke infections)).

I don’t know of any proven formulae to estimate production losses from fluke egg counts (but see what Brockwell and others found), although there have been attempts to create prediction equations based on numbers of liver fluke (as opposed to egg counts), e.g. Hawkins and Morris, 1978.

The situation with cattle roundworm egg counts might be similar to that for liver fluke egg counts. A large count means something, but there can be production losses, and even clinical disease (e.g. type 2 ostertagiosis),when WECs are low or zero.

With low or zero fluke egg counts it is possible to have production losses(not least in dairy cattle) and even clinical disease (including death) because the test is not highly sensitive and because, within the prepatent period of 10 weeks or so, immature fluke in large numbers can do a lot of damage.

Broadly speaking, I think any positive fluke egg count in grazing livestock is significant, especially if there are positive counts in repeat testing of livestock. Unless there is good reason to suggest the positive counts are all in imported animals with fluke infections from elsewhere, a strategic program should be considered. This could be as little as a fluke drench in April/May (early winter), the single most important time to drench for fluke in most of southeast Australia. Heavily infected properties may need 2, 3 or even 4 drenches more year. See Boray, 2007.

An integrated approach will also include grazing management, which basically boils down to minimizing infection of particularly vulnerable stock (sheep, and young cattle), especially if they are destined for slaughter within withholding periods of flukicides that might otherwise be necessary. Most flukicides have long withdrawal periods before slaughter if used in meat-producing animals and before milk from treated livestock can be used for human consumption (Merck). But this varies; check the label. See https://portal.apvma.gov.au/pubcris.

Prevention of livestock access to snail-infested pasture while desirable may sometimes be a challenge because of the size of the areas involved and the consequent expense of erecting adequate fencing. However, benefits could include improved productivity and fewer liver condemnations at the abattoir.

Although molluscicides can be used to reduce lymnaeid snail populations, those that are available all have disadvantages that restrict their use (Merck). The snails also reproduce rapidly and quickly re-colonise suitable habitats. Engineering solutions such as draining wet areas are another option if feasible.

Good times to test for fluke are also the traditional (Australian) strategic fluke drenching times, early winter (April/May), early Spring (August) and summer.

Having encountered positive fluke egg counts, an immediate fluke drench may or may not be warranted.  For example, if it is March, can the drench be put off until April/May (when you might get more bang for your buck?), especially if this coincides with other reasons to yard animals? Part of the decision-making process involves gauging the effect on animals. As with cattle roundworms, objective measurements of productivity, e.g. growth rate, will aid decision making, in addition to egg counts, and visual appraisal of animals.

Remember also that flukicide resistance has been recorded. (“Anthelmintic resistance by F hepatica to various compounds, including albendazole, clorsulon, and triclabendazole, has been demonstrated” (Merck)). In Australia, I am aware of resistance being found to triclabendazole (TCBZ) and to closantel. The prevalence of flukicide resistance seems to be somewhat lower than for cattle and sheep roundworm resistance to broad-spectrum drenches, but that may be an impression based on scant information. Brockwell and others (2014) have done some investigations into flukicide resistance using the CAELISA. Of eight cattle farms (NSW and Vic) tested by Brockwell and others (2014), using the CAELISA (and faecal egg count reduction test), the CAELISA found that triclabendazole efficacy was below 90% on five of the farms. Note that these were mostly if not all farms where reduced efficacy of TCBZ was previously suspected.

Consider testing after treatment to make sure the drench worked. If using a fluke egg count, test on the day of drenching and again 28 days later. (This time period is different from DrenchChecks for sheep and cattle roundworms, which are 10 and 14 days respectively after treatment). Liver fluke may take longer to die and their eggs can take longer to be cleared out of the biliary system and intestinal tract.

Consider rotation of flukicides, using drenches from different families: eg a triclabendazole-based drench in April/May, followed by say a closantel-based drench at the next treatment. In cattle there is the added option of combination fluke drenches – Nitromec and Nitrofluke, which contain two-unrelated flukicides, clorsulon (a sulphonamide) and nitroxynil (a phenol), and also drenches containing clorsulon (often combined with a broad-spectrum drench).

References:

Boray JC, 2007. Liver fluke disease in sheep and cattle. NSW DPI PrimeFact 446. Accessed July 2016 at http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0004/114691/liver-fluke-disease-in-sheep-and-cattle.pdf

Brockwell YM et al 2013. Coproantigen vs FEC cattle Fasciola and following triclabendazole Vet Para 2013 (Shortened reference).

Brockwell YM, Elliott TP, Anderson GR, Spithill TW, and Sangster NC. (2014). Confirmation of Fasciola hepatica resistant to triclabendazole in naturally infected Australian beef and dairy cattle. International Journal for Parasitology: Drugs and Drug Resistance.Volume 4, Issue 1, April 2014, Pages 48–54.   See summary and other information at: https://wormmailinthecloud.wordpress.com/2014/11/24/wrml-2014-11-24-triclabendazole-resistant-liver-fluke-in-new-england-nsw-etc/

Hawkins CD and Morris RS, 1978. Depression of productivity in sheep infected with Fasciola hepatica. Vet Parasitol., 1978. (Thanks GK).

Hutchinson GW, 2003. Validation of French antibody ELISA for liver fluke. MLA project AHW.021 : June 2003 : final milestone report.

Meat and Livestock Australia (MLA). For example: “MLA’s recently released report Priority list of endemic diseases for the red meat industries  listed liver fluke as a disease with a $25 million/year impact on sheep, while also affecting goats (sixth most costly goat disease) and cattle”.  http://www.mla.com.au/news-and-events/industry-news/what-you-need-to-know-about-liver-fluke/    Regarding the ‘priority list…”, the hyperlink above no longer works.

Merck Vet. Manual. Accessed July 2017: http://www.merckvetmanual.com/mvm/digestive_system/fluke_infections_in_ruminants/fasciola_hepatica_in_ruminants.html?qt=fasciola&alt=sh

Overend and Bowen,1995 AVJ Resistance of Fasciola hepatica to TCBZ. (Abbreviated reference).

Radostits et al, 2007. Veterinary Medicine, 10th Ed., 2007. Edited by Radostits et al. ISBN 978-0-7020-2777-2.

Woodgate R, Cassidy T and Love S, 2016.  Laboratory detection of Fasciola hepatica in live sheep, Proceedings, District Veterinarian Conference 2016. Accessed at http://www.flockandherd.net.au/sheep/reader/fasciola-detection-live-sheep.html July 2016.

SL, July 2016.

Young Alumni Faculty Award for Outstanding Achievement

Dr Evelyn Walker (BVSc ‘08)

Dr Evelyn Walker

 

“Dr Evelyn Walker is currently a District Veterinarian at Central West Local Land Services in Dubbo. She received a BSc degree in Biology from the University of Texas at Dallas and a BVSc from the University of Sydney.

Dr Walker completed a postgraduate course in production animal pathology and is also working on a PhD on chlamydial arthritis in lambs. She was instrumental in investigating drench resistance in her local area and promoting its findings to sheep producers.

Dr Walker is hearing impaired and trained Hank, from the Dubbo City Pound to be her hearing assistance dog whilst at home. Despite these challenges, they have not prevented her from mentoring veterinary students and becoming a pillar of support and expertise to the community.”

Source: http://sydney.edu.au/vetscience/alumni/awards2016.shtml

(Dr Neil Cooper: thanks for the heads up).

The  work by Evelyn and other DVs is mentioned here: https://wormmailinthecloud.wordpress.com/2013/02/13/wrml-drenches-sundry-and-various/?iframe=true&theme_preview=true

Report by Evelyn and others on sheep drench resistance in the Dubbo region: http://www.flockandherd.net.au/sheep/reader/anthelmintic-resistance-survey.html

‘iasis or ‘osis’

Regarding the notes on Fasciola above, is the disease cause by ‘fluke fasciolosis or fascioliasis? In the olden days, you would have been corrected if you got it ‘wrong’. These days it seems osis and iasis or more or less interchangeable, as intimated below in the dictionary entry on ‘ostertagiasis’.

Once upon a time people also worried about split infinitives, but now one might be more preoccupied with split ends, or even Split Enz in the case of old rockers.  As to split infinitives, I usually forget what they are, or, to put it another way, recognising the evolution of English (‘Manglish’?), ‘I have no visibility on that’.

As to osis and iasis, I remember which is which (if it still matters) by remembering Dr Joe Boray’s usage in the NSW DPI Primefact on liver fluke disease (fasciolosis),

‘ostertagiasis’

‘A disease of ruminants caused by invasion of the abomasum by Ostertagia spp. Two forms occur. Type I is in lambs or calves in their first summer at pasture and is characterized by the presence of large numbers of adult worms in the abomasum, profuse watery diarrhea, depressed appetite and a high morbidity rate. Type II occurs in cattle in the late winter after that first summer and sometimes in adults. It is characterized by emergence of large numbers of inhibited larvae from the abomasal mucosa, by chronic diarrhea, emaciation, a high death rate and a greatly thickened and edematous (sic) abomasal mucosa, subcutaneous edema and high plasma pepsinogen levels. The timing of the two forms varies between countries’.
‘The disease is more properly referred to as ostertagiosis but common usage is ostertagiasis.’
‘Saunders Comprehensive Veterinary Dictionary, 3 ed. © 2007 Elsevier, Inc. ‘
SL, Armidale. 2016-07-28
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WRML.2016-07-26.WormFax.Barbervax-update. etc

In this issue

  • WormFaxNSW – June
  • Barbervax – update – Dr David Smith
  • Oesophagostomum vs Chabertia
  • Shibboleths
  • How the internet was invented
  • Supersonic low cost magnesium
  • Coffee continues to get good press

WormFaxNSW – June

The latest issue of WormFax is up on the DPI website:

http://www.dpi.nsw.gov.au/about-us/publications/publications/wormfax

This is a summary of sheep worm egg counts done through the State Vet Lab at Menangle, and Veterinary Health Research at Armidale. Many thanks to both labs.

Moss Vale district scored the highest strongyle worm egg count, with the average in a WormTest of 2752 eggs per gram (99% Haemonchus), narrowly eclipsing Armidale ( av. 2716, 98% Haemonchus) and the South East region/Local Land services, with an average 2240 epg (99% Haemonchus).   The highest liver fluke egg count was 45 epg and this was from Cooma.

Why Haemonchus in winter?   It’s eggs are cold- and desiccation-intolerant, but its infective (L3) larvae, not so much. Third-stage (L3) larvae produced in autumn survive over winter, albeit in declining numbers.

Barbervax – the state of play.  July 2016

Dr David Smith, Moredun Research Institute, Scotland

“Background

Barbervax is a vaccine that protects sheep against barber’s pole worm (Haemonchus contortus). Launched in Armidale, New South Wales in October 2014, it is the first vaccine in the world for a sheep worm and is the culmination of more than 20 years research at the Moredun Research Institute in Scotland. The vaccine is made in collaboration with the Department of Agriculture and Food Western Australia at its Albany laboratory, where the final development phase was funded by Meat and Livestock Australia.

Performance in Lambs

During the last two summers Barbervax has been used in some 250,000 lambs, mainly in the Northern Tablelands, where barber’s pole is endemic and anthelmintic resistance common. Free egg counts were offered to all users so that the performance of the vaccine could be monitored to some extent. Provided the recommended vaccine schedule was followed, lamb egg  counts were suppressed to levels below or close to the drench threshold of 1,000 epg recommended by Wormboss (http://wormboss.com.au ). (This threshold has been set to prevent build up of larvae on the pasture and future infection. Clinical signs or deaths caused by Haemonchus don’t usually arise until egg counts reach 5,000 epg or more).  Graphs summarising these results can be found at http://barbervax.com.au

Use in adult sheep

Initially Barbervax was registered for  lambs only, but permission to use it in adult sheep was granted in late 2015 and so the vaccine will also be available for hoggets and breeding ewes during the forthcoming 2016/17 season. A few producers used the vaccine “off label” in hoggets and ewes last summer. Examples of vaccine performance on some of these properties as well as recommended vaccination schedules for  hoggets and ewes whether vaccinated in a previous season or not can be found at http://barbervax.com.au

Barbervax customers will continue to  be offered two free worm tests for each class of sheep they have vaccinated during the high risk period (January to April) so that general vaccine performance can continue to be monitored.

Barbervax supply

Initially the supply of vaccine was limited, but this obstacle has now been overcome and so future production is expected to be able to meet demand.

In addition to the usual 250ml packs, during the 2016/17 season and beyond Barbervax will also be available in 100ml amounts.  Using the smaller pack size will be more cost effective when the number of sheep to be vaccinated is not close to a multiple 250.

Thanks to favourable results with trials of Barbervax after prolonged storage, its shelf life has now been extended to 33 months provided it is kept refrigerated.

 Attempts to register Barbervax for goats

Barbervax will not be registered for use in goats in Australia in the foreseeable future.

After numerous enquiries from owners, three field trials funded by Meat and Livestock Australia were conducted with a view to registering Barbervax for goats. Unfortunately the results were mixed and for unknown reasons the vaccine did not work on one of the properties. Given the relatively small number of farmed goats in the Haemonchus endemic zone of Australia, it is not considered economically viable to run the numerous trials needed to determine whether the failed trial was an exceptional result.”

Barbervax is available through Grazag in northern NSW. I understand it will be available through Landmark in southern NSW. – SL

Oesophagostomum vs Chabertia

(Oesophagostomum vs Chabertia spp in larval differentiations in lab).

Oesophagostomum and Chabertia larvae are morphologically very similar.

For more detail, see Hutchinson GW, Nematode Parasites of Small Ruminants, Camelids and Cattle, Diagnosis with Emphasis on Anthelmintic Efficacy and Resistance Testing. ANZSDP, 2009.  (Figures 1,2; Table 4; pages 23-26 approx)

http://www.scahls.org.au/Procedures/Documents/ANZSDP/Nematode_Parasites_of_Ruminants_FINAL.pdf

State Vet Lab (NSW DPI, EMAI, Menangle). They don’t differentiate between Oes and Chab larvae, but record the  result as Oesophagostomum, but may change to recording it as Oesophagostomum / Chabertia.

Dawbuts lab, Camden. The same as EMAI, except they record the result as Oesophagostomum / Chabertia

Vet Health Research Lab: The same as EMAI, and they record the result as ‘Oesophagostomum’.

SL, 2016-07-21

Shibboleths

To have street cred in veterinary parasitology, you must be able to fluently pronounce and accurately spell certain key words. Two are:

  • naphthalophos
  • Oesophagostomum  (This was misspelled on the label of a certain high profile drench product. Gasp!)

‘Eperythrozoonosis’ was one too, but the #$%^! taxonomists changed the name of E. ovis to Mycoplasma ovis.

How the internet was invented

https://www.theguardian.com/technology/2016/jul/15/how-the-internet-was-invented-1976-arpa-kahn-cerf?CMP=oth_b-aplnews_d-3

“..The people who invented the internet came from all over the world……Without Arpa (Advanced Research Projects Agency), the internet wouldn’t exist….”

Supersonic low cost magnesium

CSIRO News Release – Supersonic tech to deliver low-cost magnesium
http://www.csiro.au/en/News/News-releases/2016/Supersonic-tech-to-deliver-low-cost-magnesium

Coffee continues to get good press

http://www.abc.net.au/radionational/programs/greatmomentsinscience/features/coffee-can-play-role-in-reducing-risks-of-cancer-and-diabetes/7640766

 

SL

2016-07-26

I often have trouble with the spelling of misspelt / misspelled…

WRML.2016-07-19. drenches-goats.primefact-drenches.resilience-primelambs.poultry. Besier etc

In this issue:

Drenches for goats – Knox and Hunt, 2014
New DPI PrimeFact – on drenches (sheep, goats, alpacas)
Resilience of prime lambs to worm infection – L Kahn
WormBoss to include goats
Progress in poultry not paltry
More on Dr Besier
Beef Forum – Friday 5 August, Convention Centre, Charles Sturt University, Wagga
What to do when your solar feed-in tariff expires
Dashcam footage shows car’s near miss
Gluten-related disorders
LambEx – 10-12 August, Albury
Neenish tart – scandalous history –  and – Your next smartphone?

Drenches for goats – Knox and Hunt

I was reminded recently (thanks LPK) of MLA-supported work by CSIRO scientists Malcolm Knox and Peter Hunt on anthelmintics for goats.

The final report (retrieved June 2016) is on the MLA website: http://www.mla.com.au/Research-and-development/Search-R-D-reports/RD-report-details/R-and-D-Report-Download?itemId=257

Hmm…this link is currently not working, so here is the report:  Knox M and Hunt P. 2014.MLA Goat anthelmintics.B.GOA.0088. ISBN 9781740362276pdf

DetailsEvaluation of anthelmintic efficacy and dosing practices in goats. Project code: B.GOA.0088 Prepared by: Malcolm Knox and Peter Hunt CSIRO, Agricultural flagship Date published: July 2014 ISBN: 9781740362276 PUBLISHED BY Meat & Livestock Australia Limited Locked Bag 991 NORTH SYDNEY NSW 2059.

Summary:

Abstract: “The efficacy of 3 anthelmintics registered for use in goats, oxfendazole (OFZ), morantel citrate (MOR) and abamectin (ABA) were assessed individually and in combination against resistant strains of Haemonchus contortus and Trichostrongylus colubriformis over 3 experiments. For each experiment, goats were infected with 4000 L3 H. contortus and 8000 L3 T. colubriformis. Faecal worm egg counts (WEC) were carried out at Days 25, 28, 32, 35, 39 and 42 post infection. Treatments were applied after allocation to groups after WEC at Day 28 and slaughter of all goats occurred on Days 43-44. Treatments were: Experiment 1 – OFZ, MOR, ABA, OFZ+MOR, OFZ+ABA, MOR+ABA, OFZ+MOR+ABA delivered orally at the manufacturers recommended dose rate. The combinations were delivered sequentially. Experiment 2 –OFZ+MOR, OFZ+MOR+ABA and Monepantel (MPL) at 1.0 or 1.5 times the recommended dose rate and some groups were fasted for 16 hours before treatment. Experiment 3 – OFZ+MOR+ABA, Triguard (TRI), Scanda (SCA) and MPL delivered orally or by intra-abomasal injection. The sequentially delivered combinations showed greater efficacy than the individual anthelmintics. Feed restriction and increasing the dose rate improved efficacy of the combinations. Greater efficacy was observed against T. colubriformis when the treatment was applied intra-abomasally. MPL was highly effective in all treatments”.

Executive summary: “Producers have a number of registered veterinary chemicals at their disposal with which to manage internal parasites in goats, but they all stem from technology more than three decades old and are all blighted by varying degrees of drench resistance in the nematodes they aim to control. The efficacy of 3 anthelmintics registered for use in goats, oxfendazole (OFZ), morantel citrate (MOR) and abamectin (ABA) were assessed individually and in combination against resistant strains of Haemonchus contortus and Trichostrongylus colubriformis over 3 experiments. For each experiment, Boer cross goats were sourced from a local supplier, treated to remove helminth parasites and then infected with 4000 L3 H. contortus Gold Coast 2004 and 8000 L3 T. colubriformis Gold Coast 2004. Faecal worm egg counts (WEC) were carried out at Days 25, 28, 32, 35, 39 and 42 post infection. Anthelmintic treatments were applied after allocation to groups after WEC at Day 28 and slaughter of all goats for worm burden estimation occurred on Days 43-44. Anthelmintic treatments were: Experiment 1 – OFZ, MOR, ABA, OFZ+MOR, OFZ+ABA, MOR+ABA, OFZ+MOR+ABA delivered orally at the manufacturer’s recommended dose rate. The combinations were delivered sequentially. Experiment 2 – OFZ+MOR, OFZ+MOR+ABA (delivered sequentially) and Monepantel (MPL) delivered orally at 1.0 or 1.5 times the manufacturer’s recommended dose rate and some groups were fasted for 16 hours before treatment. Experiment 3 – OFZ+MOR+ABA (delivered sequentially), commercial equivalents to the combinations used i.e. Triguard (TRI) and Scanda (SCA) and MPL delivered orally or by intra-abomasal injection. Prior to infection with parasites, goats in this experiment were given 12 mL of 30% glucose solution by conventional oral dosing, head-up dosing, front-of-mouth dosing, intraruminal injection or intra-abomasal injection to determine the likely effects of dosing technique on oesophageal groove closure and ruminal bypass of the dose. The sequentially delivered combinations in Experiment 1 showed greater efficacy than the individual anthelmintics especially against T. colubriformis where the individual anthelmintics removed less than 50% of the worms. MOR alone or in combination was very effective against the H. contortus strain used in both Experiments 1 and 2. Feed restriction and increasing the dose rate by 1.5 times led to further reductions in worm numbers by the combinations against T. colubriformis in Experiment 2. Greater efficacy was observed against T. colubriformis when treatment with OFZ+MOR+ABA, TRI or SCA was applied intra-abomasally when compared to oral dosing. MPL was highly effective in all treatments given in Experiments 2 and 3. Unconventional dosing technique (head-up or front-of-mouth) led to a greater proportion of the glucose dose being rapidly absorbed suggesting ruminal bypass and delivery direct to the abomasum when compared to conventional oral dosing. Evaluation of anthelmintic efficacy and dosing practices in goats. This study has shown that the anthelmintics registered for use in goats when used alone are likely to have limited efficacy against contemporary strains of gastrointestinal nematodes with the exception being MOR against susceptible populations of H. contortus. A more accessible and less expensive MOR product would be highly desirable in these situations compared to the version used in these trials which is the only product currently on the market. Sequential application of OFZ+MOR+ABA and OFZ+MOR gave greater efficacy against T. colubriformis than either anthelmintic alone and this was further improved by 16 hours fasting before treatment or delivery of 1.5 times the manufacturer’s recommended dosage. It is suggested that feed restriction before treatment be promoted for goats to enable the standard recommended dose to be applied with greatest effect for products where no toxicity issues are likely. For any goats under physiological stress and where feed restriction may be detrimental to their health, the higher dose rate could be applied with consideration of likely impacts on WHP and ESI for those animals. When dosing goats, operators should be careful to place the dose over the back of the tongue to ensure delivery of the full dose to the rumen or abomasum. There have been concerns that oesophageal groove closure and ruminal bypass may reduce the efficacy of benzimidazole anthelmintics and the results affirm this to some extent. However, the outcome of the present study indicates this may not be the case for combination products as delivery direct to the abomasum resulted in an increase in efficacy against the resistant strain of T. colubriformis used”.

But note….

Resistance of worms to monepantel, believed still to be rare, has been found since (also before) this report was published. See: https://wormmailinthecloud.wordpress.com/2015/09/22/multi-drug-including-monepantel-zolvix-resistant-haemonchus-confirmed-in-sheep-on-a-farm-in-greater-sydney-region/  (This reports the ‘Greater Sydney’ case but also mentions earlier cases).

Also, you need to be aware of the characteristics of the (‘Gold Coast 2004’) isolates against which Knox and Hunt tested the drenches.  These were Haemonchus and Trichostrongylus isolates described  in a paper by Le Jambre and others. (Don’t expect that morantel  (or levamisole-not registered for use in goats in  NSW) will always do so well. As always, drench efficacy needs to be checked on each individual farm).

Perhaps feed restriction (16 hours fast in this study) before drenching goats is an alternative for dosing goats at increased dose rates (1.5x in this study)? The data in this paper indicates there is no real difference in efficacy between the two options. Owners can get more information for themselves on this by regular use of DrenchChecks.

I revisited the paper by Le Jambre et al and summarized it to some extent (E&OE). See attached Excel sheet. But check the data in both reports (Knox and Hunt, and Le Jambre et al) for yourself. Le Jambre et al 2005 Characterisation MOX resist Haemonchus etc goats Gold coast -and Knox and Hunt 2014- SUMMARY OF BOTH SL 2016-06 printed 16-7-18

Le Jambre et al 2005 Characterisation MOX resist Haemonchus etc goats Gold coast -and Knox and Hunt 2014- SUMMARY OF BOTH SL 2016-06

Anthelmintics (drenches) for sheep, goats and alpacas (NSW DPI PrimeFact)

The revised PrimeFact has been added to the DPI website:

Just how resilient are prime lambs to worm infection?

by Lewis Kahn, ParaBoss Executive Officer, July 2016

Photo credit: source/owner unknown

“We all know the difficulties that Merino lambs face from worm infection, but meat-breed (often XB) lambs might be a different matter…………….”

Get the full story here:

http://www.wormboss.com.au/news/articles/general/just-how-resilient-are-prime-lambs-to-worm-infection.php

(You will already be clued up on this if you are a ParaBoss News subscriber).

WormBoss to include goats

WormBoss will hopefully be extended to include goats this Spring.

To keep abreast with this and other happenings, subscribe to ParaBoss News.

Go to: http://www.paraboss.com.au/news.php

Progress in poultry by no means paltry

Professor Mingan Choct, head of the Poultry CRC, recently presented at a forum here in Armidale. My NSW DPI colleague, Dr Sue Hatcher, took some notes:

·        “Mingan Choct (Poultry CRC). Australians consume 46kg of poultry meat and 225 eggs per capita annually with 200,000 people depending on the poultry industry for their livelihood. In 1979 it took 60 days and 6 kg feed for a chicken to grow to 2 kg liveweight now it takes just 1½ kg of feed and 30 days. In 1979 a 2 kg hen laid 180 eggs per year now it is 300 eggs/year. Beginning with 1 cockerel and 10 hens, in five generations the net result will be nearly 70 thousand tonnes of meat. These gains have been achieved through genetic improvement as well as feed efficiency (feed accounts for 60-70% of live production costs). Science alone will not give us the answers, (we) need to effectively communicate the benefits of the science to drive adoption. ….”

(Notes published here with the permission of Professor Choct).

See also: http://www.poultryhub.org/

Myths regarding poultry production still persist, including the hoary old chestnut regarding hormones, which, if memory serves, were banned for use in poultry in Australia  50 or so years ago.

More on Dr Brown Besier

Beef Forum being held on Friday 5 August, Convention Centre, Charles Sturt University, Wagga

More information: tnugent@csu.edu.au  www.grahamcentre.net

What to do when your solar feed-in tariff expires

http://www.ata.org.au/news/what-to-do-when-your-solar-feed-in-tariff-expires

Dashcam footage shows car’s near miss with truck on Monaro Highway

http://www.abc.net.au/news/2016-06-26/footage-shows-cars-near-head-on-smash-with-truck/7544826   (Yep, they caught the driver)

Spectrum of gluten-related disorders: consensus on new nomenclature and classification

Presentation (YouTube): Prof. Alessio Fasano (Youtube): Alessio Fasano – Spectrum of Gluten-Related Disorders

LambEx – Albury 10-12 August

lambex 2016 banner Capture

Conference organizer and NSW DPI’s Lambex coordinator:  tracy.lamb@dpi.nsw.gov.au  M: 0408 443 267

The origins of the neenish tart: A sweet mystery and a little scandal

http://www.abc.net.au/radionational/programs/earshot/the-origins-of-the-neenish-tart/7585914

Your next smartphone?

http://www.gizmodo.com.au/2016/07/the-xkcd-phone-4-plenty-of-headphone-jacks-to-go-around/

SL, Armidale.

E&OE=errors and omissions excepted.

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