Equine Practitioner March 2021

The

Equine Veterinary Practitioner

The Official Publication of the New Zealand Equine Veterinary Association

MARCH 2021 Vol. 46 No. 1

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CONTENTS

MARCH 2021 Page No.

President's Report

3-4

Editorial

7-8

E-Learning Resources

9

Sublingual salivary gland carcinoma in a 15-year-old mare Alanna J Zantingh, Lisa D Schmidt, Jessica Connell

11-13

The Horse Podcasts

14

Eosinophilic Peritonitis in an Arabian Cross Gelding Jessica Fuller

15-16

Tips and Tricks for Effective Dental Radiology Lizzi Thompson

19-23

Antimicrobial Intravenous Regional Limb Perfusion: From Theory to Practice Part 1: Procedure Gal Kelmer

25-30

What is required to set up for a Distal Limb Intravenous Regional Limb Perfusion?

30 & 56

Alex Pearce EVP Front Cover photographer

31

Equine Conferences, Seminars and Workshops

32

Obituary: (Pat) Stuart Patrick Brooks Bill Bishop

33

Vetlogic Puzzle

34 & 55

Medicine Corner: When Good Jugulars Go Bad Emma Gordon

35-38

Useful Links

40

Prepubic Tendon Rupture Erica Gee

41

Therio Conference December 2020 : Synopses of Selected Papers Erica Gee

43-44

Massey Equine Homepage

45-46

Surveillance Reports: Biosecurity New Zealand

48-49

Proceedings 66th Annual Virtual AAEP Conference 2020: Selected Edited Abstracts

50-51

Proceedings 2020 ACVIM Forum-On-Demand: Selected edited abstracts

53-54

Poetry/ Song Feature: Catch The Wind - Donovan

62

EquiManagement

63

Our Advertisers

64

Eq Vet Pract 2021 March; 46 (1) iii

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THE EQUINE VETERINARY PRACTITIONER

The Official Publication of the New Zealand Equine Veterinary Association EQUINE VETERINARY PRACTITIONER EDITORIAL GROUP Joe Mayhew (Editor)

2 Owen Road, Gisborne 4010 evp.editor@gmail.com

Erica Gee (Convenor)

e.k.gee@massey.ac.nz

Mobile: 027 437 3651 Home: 06 927 7263

Lucy Russell (Secretary) Lotte Cantley (Chair EVA Edu Comm)

Gareth Fitch

Emma Gordon

Angela Hawker

Barbara Hunter

Rabecca McKenzie

Katie McKinlay

Luca Panizzi

Tim Pearce

Trish Pearce

Andrea Ritmeester (NZEVA Executive Rep)

Lucy Holdaway

HOW TO SUBMIT PAPERS FOR PUBLICATION Papers for publication in The Equine Veterinary Practitioner (EVP) should be sent to the Editor in electronic form. Authors are requested to follow the usual EVP format for the front page of a paper including name(s) and address and email for contact author. The Editor must be made aware of any copyright matters and any appropriate acknowledgments.

HOW TO ADVERTISE Please direct all advertising inquiries to Tony Leggett (NZ Farm Life Media) on 027 4746 093 or tony.leggett@nzfarmlife.co.nz.

A full media kit for the publication is available on request.

DISCLAIMER “The Equine Veterinary Practitioner” is published by the NZ Equine Veterinary Association (NZEVA) a branch of the NZ Veterinary Association Incorporated (NZVA). The views expressed in the articles and letters do not necessarily represent those of the editorial committee of the NZEVA, the NZEVA executive or the NZVA, and neither NZEVA nor the editor endorses any products or services advertised. NZEVA is not the source of the information reproduced in this publication and has not independently verified the veracity of the information. It does not accept legal responsibility for the truth or accuracy of the information contained herein. Neither NZEVA nor the editor accepts any responsibility whatsoever for the contents of this publication or for any consequences that may result from the use of any information contained herein or advice given herein. The provision is intended to exclude the NZEVA, the NZVA, the editor and the staff from all liability whatsoever, including liability for negligence in the publication or reproduction of the materials set out herein.

COVER PICTURE – Mustering for weaning on a Sheep & Beef farm in the Ruapehu region - best done on horses.

Image by Alex Pearce. Alex is the creative mind behind Alexandra Tresta Creative Studio, based on a 400 hectare sheep and beef farm down the Ruatiti Valley under cover of Mount Ruapehu. The cover picture bears witness to the local landscape and to the joy of the irreplaceable working relationship between horse, dog and man to get the job done.

Alex has supplied several cover pictures for EVP; see page 31 for further examples of her work.

Photo credit: Alexandra Tresta Creative Studio 027 256 6484 | alextpearce@outlook.com The EVP Editorial Group would like to invite NZEVA members contribute to the photographic art we display on the front covers, so please feel free to send any potential photos to evp.editor@gmail.com. These may be of an artistic, clinical, industry, social or humorous theme as long as they relate to Equidae.

We may even spring for a prize for best contribution each year! So get your cameras out, scrutinise your hard disks and contribute.

AUSTVET ENDOSCOPY

NZ EQUINE VETERINARY ASSOCIATION EXECUTIVE COMMITTEE Andrea Ritmeester (President)

nzevapresident@gmail.com

027 575 4272

Alex Leander (Secretary)

nzevasecretary@gmail.com

021 179 1126

Roisin McQuillan (Treasurer)

Lucy Holdaway

Katie Kindleysides

Brendon Bell (President-Elect)

Alanna Zantingh

Mike Fitzgerald

Leigh DeClifford

YOUR NZEVA CONTACT PEOPLE Continuing Education

Charlotte Cantley charlotte.cantley@vets.org.nz

Dentistry

Katie Kindleysides katiekindleysides@gmail.com Glenn Beeman mountainviewequinenz@gmail.com

Endoscopy

Ivan Bridge ivan@vetassociates.co.nz

EVP Journal

Erica Gee e.k.gee@massey.ac.nz

Farriers

Tim Montgomery temonties@xtra.co.nz

Grooms Scheme

Ivan Bridge ivan@vetassociates.co.nz

Insurance

Brendon Bell brendon@southernvets.co.nz

Medication

Andrew Grierson andrew@aucklandvets.co.nz

Radiography

Alec Jorgenson ajorgi@yahoo.co.uk

Website

Tim Montgomery temonties@xtra.co.nz

Young Members

Lauren Kubala lauren@vetassociates.co.nz

LIAISON WITH NZ Equine Health Association

Ivan Bridge ivan@vetassociates.co.nz

NZ Equine Research Foundation

Noel Power noel.a.power@gmail.com

Racing Authorities

Andrew Grierson andrew@aucklandvetcentre.com

Sport Horse

Celia Grant vet@helpmyhorse.co.nz

Eq Vet Pract 2021 March; 46 (1) vii

NEW ZEALAND EQUINE RESEARCH FOUNDATION

VETERINARY SCHOLARSHIPS AND GRANTS http://www.nzerf.co.nz/

TRAVEL AWARDS For any travel relating to research and development in the NZ horse industry. http://www.nzerf.co.nz/travel_awards APPLICATIONS RECEIVED ANY TIME VETERINARIAN – FARRIER SCHOLARSHIPS $3,000 for a veterinarian and a farrier to attend a suitable course or symposium and/or spend time with colleagues in the USA http://www.nzerf.co.nz/travel_awards CLOSES 30TH NOVEMBER ANNUALLY VALACHI DOWNS YOUNG ACHIEVER AWARD $15,000 available annually to assist an individual under the age of 35 in their career in the equine industry http://www.nzerf.co.nz/valachi downs young achiever CLOSES 10TH JANUARY ANNUALLY JONATHAN HOPE EQUINE VETERINARIAN SCHOLARSHIP $10,000 available annually to help a “young at heart” New Zealand-based veterinarian to travel and gain practical skills that will be valuable in supporting his or her work within the NZ horse industry. http://www.nzerf.co.nz/hope_scholarship CLOSES 10TH JANUARY ANNUALLY EQUINE RESEARCH GRANTS Applications from interested people for funding or projects in the field of equine research. http://www.nzerf.co.nz/research_grants CLOSES 30TH APRIL ANNUALLY PROF CHG IRVINE MEMORIAL SCHOLARSHIP Research Grant may be used as part of a larger research project or as a standalone award. http://www.nzerf.co.nz/memorial_scholarship CLOSES 30TH APRIL ANNUALLY APPLICANTS SHOULD APPLY IN WRITING/EMAIL TO: The Secretary, NZ Equine Research Foundation, P O Box 52, Palmerston North Email allan.fenwick@xtra.co.nz

See the latest NZERF bulletin here 2 Eq Vet Pract 2021, March; 46 (1)

PRESIDENT’S REPORT - MARCH 2021 Andrea Ritmeester, NZEVA President nzevapresident@gmail.com

2021 CONFERENCE Despite on-going Covid-19 restrictions around the world, the 2021 NZEVA conference will go ahead as planned at the Wigram Air Force Museum in Christchurch from Wednesday 23rd to Friday 25th June, with the VetPD Workshop to be held at Canterbury Equine Clinic on Saturday 26th June, 2021.

However, because a travel bubble with Australia is still some way off and is now very unlikely to be in place by June, we have had to alter the programme slightly. We have now confirmed Dr Katharyn Mitchell to speak on topics including Fever of Unknown Origin, Equine Cardiology, Fluid Therapy in the Field for Foals and Adults, and Assessment of Colic.

After graduating from Massey University in 2003, Katharyn completed internships in equine medicine and surgery at the University of Sydney in 2003 and at the University of Melbourne in 2004-2005. She spent several years in private practice before completing a residency in large animal internal medicine at Cornell University, USA, and becoming a Diplomate of the American College of Veterinary Internal Medicine (Large Animals) in 2010. In April 2013, Katharyn started a PhD in equine cardiovascular medicine at the University of Zurich in Switzerland, which she successfully defended in 2018. Kathryn is currently in New Zealand, working as a locum and as a consultant specialist in large animal internal medicine and cardiology.

We have also confirmed Dr Ben Sykes from the University of Queensland to present lectures on Gastric Ulcers in Horses and Foals, and on Gut Health and on Parasitology. Ben graduated from Murdoch University in 1997 and completed an internship at Randwick Equine Centre in 1998 followed by a residency in Equine Internal Medicine in Virginia (USA,) gaining his Diplomate Registration in Equine Internal Medicine in 2004. He then spent 7 years in Finland as Head of the Veterinary Department of Equine Medicine and Surgery.

Ben has a special interest in equine gastric ulcers, with many peer-reviewed publications to his credit. He is an Associate Professor in Equine Internal Medicine at Massey University and an Honorary Lecturer at the University of Liverpool in the postgraduate certificate programme.

Unfortunately, because of on-going travel restrictions between Australia and New Zealand, Dr Brian Anderson is unable to attend the June conference and therefore the planned upper airway endoscopy lectures will now be postponed until the 2022 conference. Friday 25th June will feature the VetPD lectures on equine sports medicine and rehabilitation, featuring Dr Kylie Huxford and Dr Alex Jorgenson, followed by the Workshop on Saturday 26th

June. Thursday 24th June will also see the return of the ever-popular short How-to Sessions in a separate stream alongside the main room. This will feature a diverse range of topics from “How to perform a thoracic ultrasound with a rectal probe” to “How to diagnose pregnancy in a mini”.

Sam Hazeldine, Young Entrepreneur of the Year and founder and managing director of Australasia’s largest medical recruitment company MedRecruit, has been booked as the plenary speaker. Sam is a world leader and advocate for doctor wellbeing and has created the wellbeing organisation MedWorld to assist doctors to live better lives. Sam is known to be an excellent speaker who weaves education with entertainment to engage audiences at a core level to drive positive change.

As always there will be the NZEVA AGM, at which I will be looking forward to handing over the mantle of President to Brendon Bell. We also have the NZEVA Awards Dinner on Thursday 24th June, proudly sponsored by Randlab, to honour the winners of the Massey University best Young Practitioner’s Presentation, the Jonathan Hope prize for best publication, and, of course, the Brian Goulden award for outstanding NZ equine veterinarian. As always this should be a great night, with the presentation of our annual awards, great food, and live music, and we hope to see you there!

NZEVA EXECUTIVE With the now much more familiar modality of Zoom we have successfully restructured the NZEVA executive away from the historic rotating region-based executive to a more standard national executive with regional representatives. The current committee boasts members hailing from South Auckland to Invercargill! In order to complete this restructuring process, the committee will send out a call for new committee member nominations next month, with the aim to replace the remaining 4 Waikato committee members who are finishing their 3-year term at this year’s AGM. If there are more than 4 nominations, there will be an electronic ballot prior to the AGM. Anyone interested in being on the NZEVA executive committee can contact me directly or contact the secretary at nzevasecretary@gmail.com.

SUCCESSFUL OUTCOME OF THEILERA EQUI RESPONSE A declaration of New Zealand’s freedom from the equine blood disease Theilera equi was recently posted on the World Organisation for Animal Health’s (OIE) website.

Eq Vet Pract 2021 March; 46 (1) 3

In April 2020, a four-year-old thoroughbred mare destined for stud in Australia tested positive for T. equi in routine predeparture testing. Gene sequencing testing then confirmed the horse was infected with T. equi, although she was clinically healthy. The mare had been imported from France in February 2019 for breeding purposes. Investigations concluded that she had been infected before import to New Zealand. Because the mare had been resident in New Zealand outside of quarantine, our country lost its disease free status for T. equi, causing significant concern to the equine community who faced the possibility of a new endemic disease that could severely impact the health of the New Zealand horse population. In addition, there were extra immediate costs to horse exporters who now had to comply with the additional testing requirements associated with exporting from an infected country.

A response team of representatives from MPI and the equine industry, represented by members of the Equine Health Association (NZEHA), was set up. The best scientific and veterinary resources were assembled to assess the transmission risk and design a testing regimen to determine the extent of any spread of the disease in New Zealand. After extensive research and testing no evidence was found that the disease had spread - via ticks or other mechanisms beyond the single imported horse.

The joint effort by MPI and NZEHA has resulted in most export markets remaining accessible to New Zealand horse exports, and NZEHA spokesperson Trish Pearce says it’s hoped that the OIE declaration of freedom will see the quick removal of the extra testing requirements that most countries added last year, thus relieving the equine exporters of the extra costs and inconvenience they have faced over the past nine months. This is a great result after months of hard work!

EQUINE DENTISTRY This a reminder that from 9th May, 2021, the extraction of all equine teeth other than wolf teeth and loose deciduous teeth may only be performed by a veterinarian, and pain relief (analgesics, sedation and/ or local anaesthesia) must be used at the time of the procedure.

The owner and/or person in charge of the horse must not allow any tooth extractions to be undertaken except in accordance with the clause above. A competent (non-veterinary) person will be able to float teeth and remove loose deciduous teeth (i.e. baby teeth or caps) without a requirement to provide pain relief. A competent (non-veterinary) person will also be able to extract wolf teeth (first pre-molars); however, pain relief (analgesics, sedation and/or local anaesthesia) authorised by a veterinarian must be given to the horse at the time of the procedure. Breaching these regulations will be an offence and can result in a criminal conviction incurring a maximum penalty of $3,000 for an individual and $15,000 for a body corporate.

As the type of pain relief that needs to be provided to extract wolf teeth is not specified by the Government, the NZEVA feels that this is a great opportunity for veterinarians to advocate “best practice”. Clients must be educated that pulling teeth (including wolf teeth!) is a painful procedure and the pain relief provided should at a minimum be adequate sedation (including the analgesic butorphanol) and ideally should also include local anaesthesia of the tooth just like a human dentist would provide. As veterinarians we must strive to provide the highest level of care and welfare available; this is what sets us apart from non-veterinary equine dental providers.

Remember that it is our role as veterinarians to educate clients regarding the upcoming new regulations, and to be aware of our obligations under the Veterinary Code of Professional Conduct when we are working with, sedating for, or delegating equine dental procedures to non-veterinary persons.

I look forward to seeing you all at the NZEVA conference and the AGM in June. Please feel free to contact me regarding any matters pertaining to the NZEVA or its members.

Kind regards, Andrea Ritmeester nzevapresident@gmail.com

Kelmer G et al. Factors Associated with Surgical Site Infections in Horses: A Retrospective Study.

Israel J Vet Med. 2020; 75 (2): 3-13. http://www.ijvm.org.il/sites/default/files/kelmer_1.pdf All 198 surgical procedures performed in 167 horses between Nov 2011 and Feb 2013 at Koret School of Veterinary medicine were included. The general incidence of infection during the study period was 17%. Abdominal procedures, heavier body weight and pregnancy increased the risk of developing SSI. Nineteen samples were sent for culture and sensitivity, and the most common bacteria isolated were methicillin resistant Staphylococcus aureus (MRSA) and Pseudomonas aeroginosa.

4 Eq Vet Pract 2021, March; 46 (1)

BRIAN GOULDEN AWARD

NZ EQUINE VETERINARY ASSOCIATION

The Brian Goulden Perpetual Trophy will be awarded annually and presented at the Annual Dinner of the NZEVA conference.

This annual prestigious prize is awarded to members or past members of the NZEVA who have shown leadership, enterprise, contribution to knowledge or education, and have made significant contributions to the equine veterinary profession in New Zealand.

Please send your nominations including name, address and qualifications, together with any supporting information for the nominee, whom the nominator considers merits the award. This can include curriculum vitae, letters of support and documentation of achievements etc.

Send all details AT ANY TIME to: nzevasecretary@gmail.com Andrea Ritmeester, NZEVA President Elect, nzevapresident@gmail.com

YOUR CHANCE TO WIN $150.00!

All you must do is write a clinical report that is published in the EVP, and your contribution may be eligible for one of several prizes of $150.00 that the EVP has available each year.

The EVP Editorial Group wish to promote the sharing of your interesting cases and practice tips with the wider equine veterinary community, so please contribute.

Every case, technique, test and interpretation are different, no matter how experienced we are or how routine the case is, so there is always something for us to learn from each other.

Take photos, dig out your diaries, get keyboard tapping and share your views with colleagues. You could be $150.00 richer for it!

Please send your clinical reports to the EVP Editor for consideration.

Joe is happy chat with you about any articles or ideas you might have.

Please contact Joe at

evp.editor@gmail.com or on 027 437 3651.

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Eq Vet Pract 2021 March; 46 (1) 5

CONFERENCE WORKSHOP

Sport horse medicine, orthopaedics & rehabilitation A custom course for NZ equine practitioners EQUINE VETERINARIANS

Equine practitioners working with sports horses are under considerable pressure to keep the horses under their care competing at the highest level at all times.

Furthermore, evaluating poorly performing competition horses can be a daunting task because the clinical signs caused by different conditions may be very similar.

The lectures at the NZVA conference will provide an overview on the most important topics in sports horse internal and orthopaedic medicine and introduce sport horse rehabilitation foundations.

Practical tips and tricks will be shared with attendees in an intimate and interactive setting.

The workshop will provide 6-7 hours of practical sessions allowing participants to further their practical skills on live horses in small groups.

The groups will rotate through the practical sessions supervised by specialists.

TUTORS Emmanuelle van Erck DVM PhD Dipl.

ECEIM European Specialist in Equine Internal Medicine Kylie Huxford BVSc MANZCVSc Dipl.

ACVSMR Registered Specialist Veterinary Sports Medicine and Rehabilitation Alec Jorgensen BVSc Cert Ep Dipl.ABVP Eq - (NZ) Registered Specialist in Equine Surgery Kirsten Gollan MSc MNZSP

DATE Lectures: 25 June 2021 Workshop: 26 June 2021 VENUE Lectures: Air Force Museum, Wigram, Christchurch Workshop: Canterbury Equine Clinic, Prebbleton, Christchurch PRICING See conference pricing Workshop is an additional item to the lectures.

Prices are in NZD and include 15% GST. CPD POINTS Up to 15 CPD activity hours.

Register at nzva.org.nz/2021conference/june-conference/workshop For more educational resources and courses visit www.nzva.org.nz/professionals/edhub

EDITORIAL – MARCH 2021

Following on from several responses from practitioners, we have been in touch with veterinary librarians who are very appreciative of the limitations in private practice for searching the literature, saving a personal library, and accessing full articles when not affiliated with a full library service. We do plan on publishing short papers to assist in these aspects of continuing education, but in the meantime it is worth looking at this short video introducing UNPAYWALL. Unpaywall is a way to legally find free, open access versions of journal articles. It exists as a plug-in for Firefox and Google Chrome; well worth having as an add-on app.

I don’t know about you, but as much as we love our doggies, it is somewhat off-putting, and a tad embarrassing if someone is watching, to see them rolling in poo, that can be from a variety of species, including horses! Somewhat amazed, I found that very learned folk do study HMR-behaviour horse manure rolling-behaviour, for those of us who needed educating, and have published in high-ranking journals [Zhou et al. Why wild giant pandas frequently roll in horse manure.

Proc Nat Accad Sci [2020; 117(51): 32493-32498]. So, I learnt that even Giant Pandas are very good at HMR behaviour and researchers believe they have uncovered that these great creatures do it even more in cold weather.

Modified from Science News Furthermore, this behaviour likely is because of a chemical present in fresh horse shit that inhibits a cold-sensing protein in panda skin, helping the bears feel warm after an enjoyable rollicking in horse manure. Think we shall make sure our doggies are toasty warm next winter.

Some of us, like me, are prone to various injuries while trying to keep fit - meaning we keep ACC and physios busy. Father Time and Mother Nature sure do a good job though I must say that cold therapy early on appears to be well accepted as therapeutic, and deep warmth applied locally certainly can feel beneficial on more chronic damage. Otherwise, I am rather sceptical of gadgets – and there is a plethora of them out there - to speed up recovery from such athletic damage to equine as well as human tissues. http://cwtinc.com/

Notwithstanding, I did recently come across some data on the application of alternating cold and hot therapy (i.e. contrast therapy) to horses, specifically aimed at digital tendonitis. The paper [Haussler et al. Eq Vet J. 2021; 53(1): 149-156. https:// doi.org/10.1111/evj.13278] uses a commercial contrast therapy unit http://cwtinc.com/ to effect rapid changes in superficial heating and cooling while measuring temperature changes beneath the DDFT using implanted thermistors.

Authors conclude that cooling and heating of tissues to the depth of the DDFT was consistently achieved.

It seems that I am endorsing fads in our profession, and this item may be seen as such. Proclaimed to be a system to restore REM sleep in horses, the REM™ Restorative Equine Mask is claimed to ‘facilitate the melatonin rise needed https://xpertequine.com/ for sleep and recovery, improving overall performance’. Not too sure about that claim, but certainly, reducing shorter wavelength [blue] light with amber tinted lenses can have considerable, though reasonably short-lived, effect on sleep patterns [Burkhart K., Phelps JR. Amber lenses to block blue light and improve sleep: a randomized trial. Chronobiol Int. 2009; 26(8): 16021612]. There are many, many factors influencing sleep patterns, but if managerial and morbid reasons for adultonset sleep attacks in horses, such as lack of sentinel herd companion and painful processes restricting recumbency, can be ruled out, then use of such a mask as trial therapy might be worth suggesting?

To see these sorts of equations in Materials & Methods often is enough to put us off a whole paper. However, I did persevere with one such paper recently that gave an historical progression of how AI, big data, evidence credibility and diagnostic models using inferences to be made from uncertain data, can be applied to diagnosis of equine diseases. The paper was from Chinese workers [Gao H et al. An equine disease diagnosis expert system based on improved reasoning of evidence credibility. Inform Process Agric. 2019; 6(3): 414423. https://doi.org/10.1016/j.inpa.2018.11.003] who wish to develop rapid, accurate diagnostic programs because of the dearth of experienced equine vets in China. We may scoff at

Eq Vet Pract 2021 March; 46 (1) 7

these developments, but I am sure we will see such programs rapidly being applied in western society. An equine disease diagnosis expert system was established based on weighting of signs agreed by experts and on improved reasoning of evidence credibility. It appeared to be capable of reliably diagnosing 40 of the most common equine diseases and a functional evaluation of the system was conducted giving a diagnostic accuracy of 88%.

Diagnostic Accuracy =

True Positive + True Negative All types of diagnosis TP+TN+FP+FN

= 88%

The authors concluded that these test results suggest that the proposed system provides better diagnostics results than [the selected Chinese practicing] veterinarians.

Well, I certainly have banged-on about equine welfare issues in the last year or so, but highly respected scientists at the Universities of Melbourne and Sydney have joined forces to give us the low-down in their paper [Animals. 2020; 10(12), 2237] on the hot topic of Social License to Operate (SLO) that refers to the implicit process by which a community gives an industry approval to conduct its current business activities.

I can here do no better than to fully endorse the authors’ Summary:

“Social license to operate (SLO) is the process by which a community grants or withholds permission to an industry to conduct its business. This article describes how animal welfare has recently become arguably the most crucial consideration underpinning SLO for Australian animal use industries in the past decade. Such industries include animal racing, wildlife harvesting, and the farming and live export of livestock. We posit that these industries are at risk of loss of SLO unless policies shift to proactive engagement with stakeholders and transparent monitoring of animal welfare outcomes”. Ämene to that.

Noho ora mai, nä Joe evp.editor@gmail.com

The Illustrated Horse Doctor Ninth Edition. 1876 Edward Mayhew

Arndt S et al. Clinical and diagnostic findings, treatment, and short- and long-term survival in horses with peritonitis: 72 cases (2007-2017). Vet Surg 2021; Early Access. DOI: 10.1111/ vsu.13564 There were 72 horses that reached the essential inclusion criterion of a peritoneal fluid nucleated cell count of ≥ 25 000 cells/µL. Cases with GI rupture and cases occurring after abdominal surgery or castration were excluded.

Colic was the most common presenting complaint (34/72 [48%]) and a definitive diagnosis was made in 44 (44/72 [61%]) cases. The most common cause was infectious agents (31/72), followed by trauma (8/72), gastrointestinal thickening (3/72), and eosinophilic peritonitis (2/72). Idiopathic peritonitis was identified in 28 (28/72 [39%]) cases. Sixty (83%) horses survived to hospital discharge. Long-term follow-up was available for 49 horses, with 43 (88%) horses alive one year later. History of colic and positive peritoneal fluid culture result were associated with a lower survival.

Nottle BF et al. Fibro-Osseous Lesions Of The Craniofacial Complex In Horses: 30 Cases (20012019). Vet Surg. 2021; Early Access. DOI: 10.1111/vsu.13559 A definitive diagnosis of fibro-osseous lesions of the craniofacial complex in horses is made from results of histopathology and cannot be determined based on clinical presentation alone. Of the thirty horses evaluated for fibro-osseous lesions of the skull, 20 had ossifying fibroma, eight had osteoma and two had fibrous dysplasia.

Twelve horses were <1-year-old, and 20 of 30 lesions originated from the rostral mandible and the most common treatment was rostral mandibulectomy. Recurrence was not reported after complete excision. Incomplete excision was confirmed in eight horses with recurrence occurring in one horse, while six horses had long-term resolution of clinical signs. Prognosis for survival and return to use was excellent in the 23 horses with long-term follow-up.

8 Eq Vet Pract 2021, March; 46 (1)

A FEW E-LEARNING RESOURCES The effects of the SARS-CoV-2 virus and its disease COVID-19 will be with us for some time yet. One result of ‘lockdown’ has been for many groups to share E-education material. We have here collated several of these resources that may be of interest to our EVP readers; ENJOY.

Image by Tumisu from Pixabay

NOTE: some resources may require free or paid registration.

1.

BEVA Microsite. Available free to all NZEVA members at BEVA microsite.

To access videos, infographics, podcasts, and EVJ Virtual Issues and Highlighted Papers.

2.

AAEP CONVENTION RECORDINGS. American Association of Equine Practitioners.

Membership required.

3.

International Veterinary Information Service [IVIS] IVIS: Home Page. Free registration required

4.

Merck Manual https://www.merckvetmanual.com/. Encyclopaedic resource.

5.

Boeringher Academy https://www.boehringer-academy.co.uk/webinars/animal-specie/40.

Many webinars. Free registration required.

6.

Veterinary Information Network – membership required. VIN has many equine procedure videos.

7.

International Society of Equine Locomotor Pathology [ISELP] – Free Webinar: Biologics in Equine Medicine, Sponsord by OWL MANOR

8.

International Society of Equine Locomotor Pathology [ISELP] – On Demand For a limited time ISELP are offering a selection of Free Lectures that are excerpts from the 2019 ISELP Sports Medicine & Rehabilitation Module. Since EVP press time, more videos may be added.

Improving Radiology of the Hock – Kurt Selberg Radiology of the Stifle – Sarah Puchalski “Shoeing” – Stephen O’Grady Equine Rehabilitation: Can We Make A Difference? – Melissa King Tendon and Ligament Injury with an Eye on Rehabilitation – Duncan Peters

9.

AVMA and AAHA have compiled several resources on TeleMedicine that are worth a view:

Veterinary Telehealth: The Basics

Virtual Care and Telehealth

As NZEVA members you have free access to the new resources. Through this site you can LISTEN, WATCH, VIEW and READ all accessible videos, infographics, podcasts, and EVJ Virtual Issues and Highlighted Papers

Eq Vet Pract 2021 March; 46 (1) 9

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10 Eq Vet Pract 2021, March; 46 (1)

CASE REPORT SUBLINGUAL SALIVARY GLAND CARCINOMA IN A 15-YEAR-OLD MARE Alanna J Zantingh Cambridge Equine Hospital

alannazantingh@gmail.com

Lisa D Schmidt SVS Laboratories

Jessica Connell Matamata Veterinary Services Equine

ABSTRACT A 15-year-old mare presented to a referral surgeon for a mass on the ventral aspect of the tongue. The lesion was surgically excised and was histologically consistent with an acinic carcinoma of the lingual salivary gland. The surgical procedure did not require specialized instruments and could easily be performed in an ambulatory setting.

IV). The mare also received pre-operative penicillin (22 mg/ kg IM), gentamicin (6.6 mg/kg IV), tetanus antitoxin (1500 IU SC) and phenylbutazone (4.4 mg/kg IV). Anaesthesia was induced with ketamine (3 mg/kg IV) and diazepam (0.1 mg/ kg IV) and the horse was placed in left lateral recumbency.

A mouth speculum was placed, and the tongue was retracted from the mouth to expose the neoplasm (Figure 1).

INTRODUCTION In horses, the most common oral neoplasm is squamous cell carcinoma which can affect any oral mucosal surface including the tongue. Glossal squamous cell carcinoma is often locally invasive, metastasises and recurs following surgical excision (Noll, 2016). Reports of other tumours of the tongue and salivary glands are rare. In the salivary glands, melanomas are the most common tumour. Lymphoma, adenocarcinoma, peripheral nerve sheath tumour and acinic cell carcinoma are reported less commonly (Auer et al., 2019; MacGillivray et al., 2002; McConnell et al., 2014; Stackhouse et al., 1998). Lingual neoplasms are rarely reported in the horse. However, there are a few reports of lingual rhabdomyosarcoma and a chondrosarcoma (Castleman et al., 2011; Hanson et al., 1993; Wilson and Anthony, 2007).

CASE HISTORY A 15-year-old mare with a body condition score of 2/5 had an intermittent history of oral haemorrhage over 6 months.

The haemorrhage was reported to spontaneously resolve.

No apparent difficulty in prehending and masticating food was noted. A sublingual mass was noticed during a routine dental examination. At a two-week veterinary recheck, the lesion was larger. The 7cm diameter x 3.5cm tall mass was adhered to the lingual ventral midline about 10cm rostral to the frenulum. The nodular lesion was pink to yellow and half the mass was friable. No other abnormalities were noted on physical examination. Due to the growing size and the location, surgical excision was recommended. At the owner’s request, gastroscopy was also performed.

SURGICAL PROCEDURE The mare was premedicated with acepromazine (0.03 mg/ kg IV), xylazine (1.1 mg/kg IV) and butorphanol (0.01 mg/kg

Figure 1: Sublingual tumour. The nodular tumour was present on the ventral midline about 10cm rostral to the frenulum.

Using sharp and blunt dissection, the mass was excised.

Grossly, the lesion was well demarcated and did not appear to invade the lingual muscle. On cut surface, the lesion was gelatinous and pale yellow to tan (Figure 2). The mucosal epithelium was brought into apposition using simple interrupted absorbable polydioxanone sutures (Figure 3).

Recovery from anaesthesia was uneventful.

A few hours after the mare recovered from anaesthesia, she was sedated with detomidine (0.01 mg/kg IV), butorphanol (0.01 mg/kg IV) and acepromazine (0.02 mg/ kg IV). Gastroscopy was performed with a standard 3 m gastroscope (Austvet, Mount Waverly, Victoria, Australia).

Eq Vet Pract 2021 March; 46 (1) 11

Figure 2: A sublingual mass was gelatinous and yellow to tan on cut surface..

Figure 4: Actinic cell carcinoma. Cells are large with vacuolated cytoplasm and form nests (A). Pyogranulomatous inflammation surrounds foreign (plant) material (B).

The mare was rechecked two and 12 weeks, and two years after discharge with the surgical site healing without complications and the mass had not recurred.

Figure 3: The mucosal epithelium was closed with metric size 3 simple interrupted monofilament polydioxanone sutures.

At the margo plicatus there were two red 2 mm nodules and three attached bot fly larvae. The nodules were thought to be associated with bot fly larval attachments. No ulcers were present. Recovery was uneventfully. Prior to discharge, the mare received a second dose of penicillin (22 mg/kg IM) and was prescribed sulfamethoxazole/trimethoprim antibiotic paste (30 mg/kg PO, BID, x 5 d) and phenylbutazone (2.2 mg/ kg PO, BID, x3 d). An ivermectin- or moxidectin-containing anthelmintic was recommended to manage the larval bot fly infection.

Histologically, the lobulated tumour was composed of sheets, tubules, and nests of neoplastic epithelial cells with moderate amounts of clear, vesiculated to pale eosinophilic cytoplasm. Nuclei were round with finely stippled and occasionally clumped basophilic chromatin. Mitoses were regularly present but not numerous. Cells were supported by a scanty to thin bands of fibrovascular stroma (Figure 4).

The overlying mucosal epithelium was ulcerated, and the subjacent tissue was separated by oedema, neutrophils, lymphocytes, and plasma cells. Within areas of inflammation in multiple examined sections having plant- and hair-based foreign material surrounded by degenerate neutrophils Occasionally the foreign material was surrounded by large colony-type bacteria. The neoplasm was diagnosed as a salivary gland acinic cell carcinoma with glossitis 12 Eq Vet Pract 2021, March; 46 (1)

DISCUSSION Neoplasms of the salivary glands are rare in horses and represents 0.2% of neoplasms in horses (Munday et al., 2017). They represent 1% of salivary gland neoplasms in people and are more common in the parotid salivary gland (Neto et al 2005). In horses, there are three pairs of major salivary glands: parotid, mandibular, and sublingual glands.

There are also smaller (minor) buccal, labial, lingual, and palatine salivary glands (Dyce et al., 2002). Based on its location, this mass likely originated from one of the minor lingual salivary glands. In general, acinic cell carcinomas are low grade malignancies. In domestic species, they are usually slow growing and have a better prognosis compared to other types of salivary gland tumours (Brunnert and Altman, 1990; Hammer et al., 2001). However, in cats, the lesions have been reported to metastasize and in dogs, they are locally invasive. While glossal tumours are rare, they often carry a good prognosis with surgical resection. (Auer et al., 2019).

Ulceration of the mucosal surface, presence of embedded foreign material and pyogranulomatous inflammation, seen histologically, was most consistent with trauma to the mass incurred during mastication. This may have contributed to the increased size of the lesion noted between finding the lesion and its surgical excision.

Unfortunately, the tan gastric nodules at the margo plicatus were not biopsied to confirm a diagnosis. At this site, the most common neoplasm is squamous cell carcinoma that carries a poor prognosis with most horses dying within four weeks of diagnosis (Auer et al., 2019). In this case, the horse had no clinical signs associated with gastric neoplasia. Clinical signs of gastric squamous cell carcinoma would include severe weight loss, inappetence, and colic. In addition, the mare survived for 30 months after discovery of the nodules. Therefore, it is more likely that the nodules were inflammatory in nature and were suspected to be related to bot fly larvae which are a common finding on gastroscopy.

This case demonstrates the importance of a good physical and oral examination. The tongue is a difficult structure to visualise in full. Use of sedation and a dental speculum are, at a minimum, necessary to examine the rostral aspect of the tongue closely. This case is also a good example of a surgically excised neoplasm in a geriatric horse. Although treatment involved surgery, it was relatively inexpensive, performed under injectable anaesthetic in a dry clean area, and had a good outcome. As this procedure did not require specialised equipment, it could easily be performed in an ambulatory situation.

REFERENCES Auer JA, Stick JA, Kummerle JM, Prange T. Equine Surgery, 5th Edition. Elsevier, St. Louis, Missouri, USA, 2019.

Brunnert SR, Altman NH. Canine lingual acinic cell carcinoma (clear cell variant) of minor salivary gland. Vet Pathol 1990; 27: 203–205.

Dyce KM, Sack WO, Wensing CG. Textbook of Veterinary Anatomy, 3rd Edition. Saunders, Elsevier, Philadelphia, PA, USA, 2002.

Hammer A, Getzy D, Ogilvie G et al. Salivary gland neoplasia in the dog and cat: survival times and prognostic factors. J Am Anim Hosp Assoc 2001; 37: 478–482.

Hanson PD, Frisbie DD, Dubielzig RR. Rhabdomyosarcoma of the tongue in a horse. J Am Vet Med Assoc 1993; 202: 1281-1284.

MacGillivray KC, Sweeney RW, Del Piero F. Metastatic melanoma in horses. J Vet Intern Med 2002; 16: 452-456.

McConnell EJ, Sanz MG, Kafka UC. Parotid salivary gland carcinoma in a geriatric horse. Equine Vet Educ 2014; 26: 610-615.

Munday JS, Lohr CV, Kiupel M. Tumors of the alimentary tract.

In Meuten DJ (ed.) Tumors in Domestic Animals. 5th Edition.

John Wiley & Sons, Ames, Iowa, 2017 Neto AG, Pineda-Daboin K, Loreto Spencer M, Luna MA. Sinonasal acinic cell carcinoma: a clinicopathologic study of four cases. Head Neck 2005; 27: 603–607.

Noll C. Equine tongue tumors: a multi-center retrospective study. Proceedings AAEP 2016; 514-515.

Stackhouse LL, Moore JJ, Hylton WE. Salivary gland adenocarcinoma in a mare. J Am Vet Med Assoc 1998; 172: 271-273.

Wilson GJ, Anthony ND. Chondrosarcoma of the tongue of a horse. Aust Vet J 2007; 85: 163-165.

Castleman WL, Toplon DE, Clark CK et al. Rhabdomyosarcoma in 8 horses. Vet Pathol 2011; 48: 1144-1150.

Pugliese BR et al. Biomechanical and wearability testing of novel legwear for variably limiting extension of the metacarpophalangeal joint of horses. Am J Vet Res. 2021; 82(1): 39-47.

A prototype legwear unit was designed to allow variable restriction of MCF joint motion [editor’s pathetic figure]. Legwear-derived force data, including peak legwear loads and torques among legwear states, treadmill gaits and stall activities were recorded under four conditions of no or restricted motion while the legwear device was applied. On the treadmill, moderate restriction of legwear extension resulted in significantly higher peak load and torque than with mild restriction. Canter vs walk or trot, and trot vs walk, yielded higher peak load and torque. During in-stall activity, maximum restriction of legwear extension yielded higher peak load and torque than moderate restriction. Unrestrained in-stall activity resulted in higher peak load and torque than restrained activity. The legwear caused minimal adverse cutaneous effects. Thus, extension of the MCP joint may be incrementally adjusted through the legwear such that return to activity, crucial for rehabilitating flexor apparatus injuries, may be controlled.

Eq Vet Pract 2021 March; 46 (1) 13

The HORSE - Podcasts Click on The HORSE – Podcast website HERE and listen to many 20-60 minute audio talks from The Horse. You may need to LOGIN/SIGNUP. You can go to a selection of these topics directly by Ctrl+Clicking on the following: • Older Horses.

Amanda Adams • Racetrack Surfaces.

Mick Peterson • Bits, Bridles, and Equine Welfare.

Hilary M. Clayton

• Vitamin E: Carrie Finno • What Does Vitamin Deficiency in Horses Look Like?

• Why Do Horses Need Vitamin • Vitamin E and Selenium: What’s the Relationship?

• Mare Reproductive Cycles and Anxiety.

Jenny Beard Biehunko

• Which is Better: Skin or Blood Test for Equine Allergies?

Susan White & Ann Rashmir

• Calming Horses: Education and Options. Camie Heleski

• Mowing Horse Pastures to Keep Them Healthy.

Krishona Martinson

• The Best Forage for Insulin Resistant Horses. Stephen Duren

• Old Gray Horses and Melanomas.

Bryan Waldridge

• African Horse Sickness.

Peter Timoney

• Basic Anatomy of the Equine Neck and Back.

Kevin Haussler

News From NEW ZEALAND EQUINE RESEARCH FOUNDATION – NZERF

Due to Covid-19 NZERF did not run their usual Rodmor Trust Lecture Series in 2020. Partly in response to this, NZERF plan to develop brief educational videos on equine topics of interest. The first of these is presented by Paul Fraser on Strangles, and the video is available to view HERE.

The NZERF Spring 2020 Bulletin is now available: also via NZERF website at https://www.nzerf.co.nz/

14 Eq Vet Pract 2021, March; 46 (1)

Secretary NZREF, PO Box 52, Palmerston North

allan.fenwick@xtra.co.nz

CASE REPORT EOSINOPHILIC PERITONITIS IN AN ARABIAN CROSS GELDING Jessica Fuller DVM, MPH jessfuller@hotmail.com

CASE PRESENTATION A 5-year-old Arabian cross gelding initially presented to Massey University Equine Veterinary Hospital for routine gastroscopy to screen for gastric ulcers. Following gastroscopy, he subsequently developed colic signs and was ultimately diagnosed with eosinophilic peritonitis. The gelding had a 2-month history of weight loss as well as intermittent diarrhoea and colic. His owners reported he was more dull than usual and tended to be reactive when tacked up, especially when the girth was tightened. The gelding resided on a farm with 10 other horses who were cross grazed with cattle. He had a routine dental prophylaxis four months earlier and was dewormed with an unknown product at that time.

INITIAL DIAGNOSTICS On presentation his physical examination was unremarkable, however his body condition score was slightly decreased at 4/9.

Diagnostic work-up included a physical examination and rectal palpation which were unremarkable. Haematology and serum biochemistry were performed and abnormalities included a low GLDH of 3 IU/L (Ref: 4-14), mild hyperproteinaemia of 84 g/L (Ref: 53-73) due to elevated globulins, mild hypocalcaemia at 2.67 mmol/L (Ref: 2.80-3.30), leucocytosis of 14.5 x 109/L (Ref: 5.7-12.0) and an eosinophilia of 3.2 x 109/L (Ref: 0.0-0.4), with fibrinogen being within the normal range at 4.2 g/L (Ref: 1.4-5.0).

Gastroscopy revealed some pink plaques in the squamous mucosa of the stomach that were not consistent with typical gastric ulceration although there was also presence of gastric ulceration along with areas of hyperkeratosis (Figure 1 A & B).

Figure 1. A & B: Two endoscopic views of atypical pink plaques on the squamous gastric mucosa

Biopsies of the plaques were taken for histopathologic examination revealing sections of stratified squamous epithelium with areas of epithelial degeneration and spongiosis. In one section there were multifocal epithelial cystic dilatations filled with eosinophilic amorphous material and inflammatory debris. In a second section, similar multifocal intra-epithelial dilatations were filled predominantly with inflammatory debris including neutrophils and lymphocytes and degenerate epithelial cells. Overall interpretation was multifocal ulceration, inflammation and oedema of the non-glandular stomach. The glandular mucosa was grossly unremarkable.

CASE PROGRESSION The patient was diagnosed with grade 2/4 squamous gastric ulceration, and while histopathology was pending, the patient was discharged with a course of omeprazole as treatment at home. On the ride home, however, he developed acute colic signs. He went down in the truck and was reportedly rolling and sweating on arrival home. An examination was performed by the referring veterinarian when he arrived home. No reflux was present on nasogastric intubation, and he was tachycardic at 60 BPM with an elevated rectal temperature of 38.9oC. He was managed with flunixin, butorphanol and xylazine however he showed minimal improvement and was referred back to Massey Equine the day following his discharge.

At his repeat examination the patient was tachycardic (68-88 BPM) and tachypnoeic (28-44 BrPM). Gastrointestinal sounds were absent on the left and decreased on the right side - that had been normal on initial presentation. Palpation per rectum revealed green, malodorous diarrhoea. The circulating PCV was 49% and total plasma solids were 96 g/L. Peripheral venous lactate was mildly elevated at 3.2 mmol/L; findings consistent with presence of dehydration.

Fluid obtained from abdominocentesis was yellow and mildly cloudy with a lactate of 4.2mmol/L and total solids of 32 g/L (Ref:l <25 g/L). Cytologic evaluation of the abdominal fluid revealed an eosinophilic-rich exudate with a total nucleated cell count of 24.1 x109/L (range 0-5 x 109/L). Cells consisted of 48% non-degenerate neutrophils, 42% eosinophils and 10% mononuclear cells with reactive mesothelial cells present.

A full abdominal ultrasonographic evaluation was performed.

There was a small amount of free abdominal fluid present as well as some fluid in the large colon. The small intestines were

Eq Vet Pract 2021 March; 46 (1) 15

subjectively slow to contract. A second abdominal ultrasound was performed 12 hours after presentation when the patient became more painful. This showed a moderately distended small intestine that was subjectively less motile than normal.

No other abnormalities were observed.

Initial treatment during the second visit included administration of routine pain relief with flunixin and butorphanol, isotonic fluid administration intravenously, application of ice booties for laminitis prophylaxis, and Biosponge™ administered via nasogastric intubation. On the fourth day of hospitalisation with return of laboratory diagnostics consistent with eosinophilic peritonitis, dexamethasone was added to his treatment plan at 0.1 mg/kg IV q24h. The patient responded well to corticosteroid administration and the manure quickly began to normalise. He was discharged the following day with a tapering course of dexamethasone consisting of 0.1 mg/kg IM q24h for 10 days, 0.07 mg/kg PO q24h for 7 days, then 0.05 mg/kg PO q24h for 10 days, with recommendation to repeat abdominocentesis prior to discontinuation.

anthelmintics, corticosteroids, flunixin, and cetirizine. The role of hypersensitivity reactions or internal parasitism in this disease process is as yet uncertain. Anecdotally, eosinophilic peritonitis has been seen with some frequency in the US, although incidence appears to be regionally dependent (E Gordon, pers. comm.).

The horse discharged from Massey is alive 22 months later, however his owners report that in work he will colic intermittently and for that reason he is essentially retired. He has not been treated by his referring veterinarian since his discharge from Massey. Follow up abdominocentesis was not pursued prior to discontinuation of corticosteroids. Based on the experience of the treating clinicians, some eosinophilic peritonitis cases require an extended course of corticosteroids for complete resolution of increased numbers of eosinophils in abdominal fluid and peripheral circulation. Thus, continuing steroid treatment is recommended until any eosinophilia has abated. No other horses on the same property are reported to have developed similar signs.

DISCUSSION

REFERENCES

On initial presentation peritonitis would be a reasonable differential diagnosis, especially with the intermittent colic, weight loss, and diarrhoea. However, eosinophilic peritonitis is an uncommon diagnosis, particularly in New Zealand. It has only been described in horses in relatively recent literature. A 2015 abstract (Smith, 2015) performed a retrospective study of peritonitis cases at UC Davis VTH, and found 8 cases that matched inclusion criteria of ≥ 10 x 109 cells/L total nucleated cells and ≥ 1 x 109 eosinophils/L in abdominal fluid. Cases in this study reported total nucleated cell counts in the abdomen to range from 10-75 x 109 cells/L. All horses had peripheral eosinophilia, as noted in the case presented here.

Five horses were suspected to have eosinophilic infiltration of abdominal organs. Arabian horses were overrepresented. All survived to discharge, and 5/8 horses survived to follow up 2-24 months later. A larger study population will be required to obtain statistically significant information regarding efficacy of treatment and prognosis. Treatment for the cases in the above retrospective study consisted of antimicrobials,

Arndt S, Kilcoyne I, Vaughan B & Dechant JE. (2021). Clinical and diagnostic findings, treatment, and short‐ and long‐term survival in horses with peritonitis: 72 cases (2007‐2017). Vet Surg. 50(2): 323-335.

Henderson IS, Mair TS, Keen JA, Shaw DJ McGorum BC. (2008). Study of the short- and long-term outcomes of 65 horses with peritonitis. Vet Rec. 163(10): 293-297.

Smith FL, Magdesian KG, Whitcomb MB. Eosinophilic Peritonitis in 8 horses (1995-2015) [Abstract]. 2017 ACVIM Forum Research Abstract Program. J Vet Int Med. 31: 12251361. https://doi.org/10.1111/jvim.14778

ACKNOWLEDGEMENTS Special Thanks to Emma Gordon, Large Animal Internal Medicine Specialist, at Massey University for her patient guidance and unending support and to Jonathan Atkins, Vet Services Dannevirke, for referring this case to Massey Equine.

FREE WEBINARS & BULLETINS The Beaufort Cottage Educational Trust is a small charity that aims to support educational projects and events for all those involved in the care of horses and disseminate knowledge of the best veterinary and management practices and thereby enhance horse welfare.

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16 Eq Vet Pract 2021, March; 46 (1)

• Gastrointestinal Disease in Foals • Herpes Virus • Foal Injuries and Diseases

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• Recurrent Laryngeal Neuropathy

• Third Phalangeal Cysts

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REGISTRATIONS OPEN 1 MARCH 2021

REGISTRATIONS OPEN 2 AUGUST 2021

NZVA and NZVNA conference

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23–25 June 2021

18–20 November 2021

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ELECTRONIC COPIES OF E-EVP

EVP E d u ca t i onal Fu nd Dear Colleagues;

You can enjoy your E-EVP Current Issue and E-EVP Archive at your NZVA login pages.

1. Go to http://www.nzva.org.nz/ and sign in 2. Click on: > FOR VETERINARY PROFESSIONALS > Branches > New Zealand Equine Veterinary Association [on left] > NZEVA Documents [on left] 3. There you have Current and Archive for E-EVP 4. Or you can View the E-EVP catalogue on SciQuest and download individual pages/articles 5. Now you also can click on a page number on the contents page to link to each item!

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DID YOU KNOW THAT YOU ARE ELIGIBLE TO APPLY FOR EVP FUNDS TO ASSIST YOU IN OBTAINING EQUINE VETERINARY EXPERIENCE, TRAINING, CPD ETC? An annual sum of money is set aside each year by the NZEVA EVP Subcommittee to establish a Continuing Education (CE) fund. The two main purposes of this fund are: • facilitating continuing education and/or specialist training for EVP Editorial Group members AND for all paid up NZEVA members at large • dissemination of such newly acquired information of benefit to New Zealand equine practitioners through publication in the Equine Veterinary Practitioner Applicants seeking assistance from the CE fund must adhere to the following guidelines: 1. Present a complete budget for the proposed CE project and identify all sources of funds being sought and the planned use of any funds awarded from this fund.

2. Demonstrate that funds awarded under this scheme were used for the stated purpose.

3. Normally present a verbal report to the NZEVA EVP Editorial Committee at the first EVP meeting held after completion of the CE project, or at the next NZEVA Annual Conference.

4. Within 60 days of the applicant completing, and/ or returning to NZ from, the CE project, submit to the Editor of the EVP a concise report of the project, identifying key new practical items of information of interest and value to NZ equine practitioners.

This report should adhere to EVP publication guidelines.

5. Applications can be made in writing to, and will be assessed by, two senior members of the EVP Editorial Committee - who are ineligible for funding.

6. The application must include a signed statement that, “I have read and understand my obligations to the EVP Editorial Committee.”

7. Approved applications can access up to 75% of awarded funds prior to undertaking the proposed travel. The remaining 25% will be paid upon receipt of an acceptable written report.

8. Except in exceptional cases, the amount awarded to any individual applicant will not exceed 50% of the available funds.

TIPS AND TRICKS FOR EFFECTIVE DENTAL RADIOLOGY Lizzi Thompson Blue Mist Equine Veterinary Centre bluemistlizzi@gmail.com

Taking dental radiographs doesn’t need to be difficult or frustrating if a few guidelines are followed.

As equine vets, we take X-rays all the time, but it can still be tricky to achieve truly diagnostic dental films due to several factors. First is the complexity of the equine skull. We need to understand the internal and external anatomy of the equine head to really make this work. Dental radiographic techniques can be a challenge; without practice, even an expensive radiographic system may still result in films of poor diagnostic quality.

Table 1: Roadmap to better dental radiographs

can occur with higher butorphanol doses. The butorphanol offers a 2-8-minute window of profound analgesia and immobility, ideal for taking radiographs or performing perineural analgesic blocks.

Stability of Sensor/Cassette Resting both the horse’s nose and the sensor on a foam mat on the same support platform (e.g. a folding table) minimises movement of both the patient and the sensor, plus the horse’s nose sinks nicely into the soft surface (Fig 1). Unfortunately, this doesn’t work so well for intraoral views of canines and incisors. An aluminium long-armed sensor holder with rubber hand grips minimises exposure to assistants and decreases likelihood of damage to the sensor.

1. Immobility 2. Labelling 3. Presentation of images 4. Separation of arcades 5. Complete studies 6. Radiographic projections 7. Use an equine skull for reference 8. The ‘Porcupine Technique’ Several excellent resources are available on specific positioning for good dental radiographs (see Bibliography), but here I will share my best tips and tricks that can help maximise radiographic diagnostic quality [Table 1]. It is obviously important to keep assistants out of the primary beam and minimise exposure to everyone around with proper radiation protection equipment including gowns, thyroid protectors, radiation monitoring devices, gloves, and longhandled x-ray plate/detector panel holder. Additionally, it is necessary to follow an appropriate technique chart for each x-ray generator and detector/cassette combination [contact the author if assistance required for this].

1. IMMOBILITY Sedation For sedation, I prefer xylazine (0.6 mg/kg IV, or 3 ml/500 kg horse of 100 mg/ml xylazine) and butorphanol (0.005 mg/kg IV, or 0.25 ml/500 kg horse of 10 mg/ml butorphanol) to achieve the lowered head posture that is ideal for equine dental radiology without the marked ataxia and head shaking which

Figure 1: Supporting the horse’s head on a soft surface for radiography.

Eq Vet Pract 2021 March; 46 (1) 19

Stability of Patient Sedated horses tend to be much more stable when contained in a sturdy set of stocks, whether portable (Fig 2) or in-clinic. It is important the front gates are low enough to prevent choking the patient and that there are quick-release mechanisms to get the horse out, should a problem occur. A folding table, or a 20L bucket in the case of a miniature, makes an excellent head support. Incisors and canine intraoral views may be easily taken using a dental halter or head stand.

Oblique: Keep it simple. If all those letters in the standard labelling nomenclature become a blur, here’s a simplification that relies on labelling for the direction of the beam (based on Barratt, 2019): Maxillary example: Rt D 30-Lt VO (open mouthed) = Right dorsal, 30° from horizontal, left ventrolateral oblique. This is shown in Fig. 3. Sensor is on the left side of the patient’s face, highlighting the apices of the 200 arcade.

Mandibular example: Rt V 50-Lt DO (open mouthed) = Right ventral, 50° from horizontal, left dorsolateral oblique. This is directing the beam from beneath the mandible towards left dorsal, highlighting the apices of the 300 arcade.

Other portions of arcades are shown, too, but let’s keep it simple for now.

Figure 3: Rt D 30-Lt VO = Right dorsal, 30° from horizontal, left ventrolateral oblique to highlight apices of the 200 arcade; the sensor is on the left side of the patient’s face.

Figure 2. Portable stocks in working position in the field, tipped upright from the integrated trailer.

Stability of generator Generators are ideally mounted on a wall or ceiling for greatest stability, but most of us in mobile practice don’t have that luxury, so keeping the kV high and the time short will help make up for the wobbles in our arms.

2. LABELLING Labelling seems to be a challenge with dental radiographs in general and oblique views in particular, and frequently labelling is inadequate for interpretation of radiographs. As with any other, dental radiographs should show the owner name, patient name, signalment, practice name, and date.

Specific views should be labelled as follows: DV/VD: Place L/R marker on side of plate/sensor corresponding to patient side.

Lateral: Place L/R marker to indicate patient side closest to the plate/sensor.

20 Eq Vet Pract 2021, March; 46 (1)

3. PRESENTATION OF IMAGES Various conventions exist on the direction the patient is facing when a radiograph is mounted, or presented, with respect to the laterality of the view. Whichever convention you choose, let those reading them know which you’re using, and labelling radiographs. It may be wise to check for preference if you will be sending them an equine dental referral veterinarian.

Labial mounting convention: Animal is facing left for a left arcade (plate on left side of horse), and to the right for right arcade. The American Veterinary Dental College (AVDC) uses this convention, which was adapted for intraoral dental radiographs.

Facing Left Convention: In this more common convention, the patient is always facing left. ACVR, AAEP, JAVMA, and other journals use this convention. As you might imagine, labelling is especially important here.

Facing Direction Taken: Still others present radiographs in the direction they were taken, and label appropriately. I personally prefer this convention.

4. SEPARATION OF ARCADES

6. RADIOGRAPHIC PROJECTIONS

Wide radiographic separation of the dental arcades allows better visualisation of individual teeth. With optimal angulation, one may see both the apices and reserve crowns on the ipsilateral side of opposing arcades. Opening the patient’s mouth prevents unnecessary summation, which makes radiographs difficult to read and often nondiagnostic.

Arcades may be separated with a simple radiolucent incisor block or aluminium speculum. Commercial X-Ray blocks are available (e.g. HDE Pegasos) (Fig. 4) or may be homemade from a block of wood. In the case of a patient with painful rostral teeth, a radiolucent tube speculum may be used.

Aluminium speculum plates are handy for radiographing incisors, but scatter from branches of a steel speculum precludes their use for cheek teeth views and does little to improve radiation safety.

Specifics of standard and selective radiographic projections are well-defined in several papers in Bibliography. But to iterate: all lateral and oblique radiographs should be taken with the patient’s mouth open.

Figure 4: Simple radiolucent incisor block.

5. COMPLETE STUDIES Table 2: A complete set of radiographic views for evaluation of cheek teeth includes: DV or VD

The Lateral view is excellent for visualisation of osteitis and sinusitis and for dental symmetry, but due to summation, its usefulness may be somewhat limited in tooth evaluation, unless severe pathology is present (Fig. 5). Mitchell markers can aid with defining obscure fluid levels. The left and right markers contain lead balls which fall by gravity to the lowest point, defining where fluid levels should lie (Fig. 6).

Figure 5: Lateral view of maxilla with severe overgrowths, periodontal disease and tooth loss.

Figure 6: Left and Right Mitchell Markers with lead balls to indicate direction of gravity.

Straight lateral Rt D30-Lt VO Lt D30-Rt VO Rt V50-Lt DO Lt V50-Rt DO It is highly recommended that complete, correctly labelled radiographic studies of the head are taken for any evaluation of cheek teeth [Table 2]. Possessing all these projections ensures you have adequate views to make a good comparative study and achieve a definitive diagnosis, or at least a good differential diagnosis, and avoid missing pathology. All obliques and laterals are best taken with patient’s mouth open, as discussed above. Other views specific to the tooth or teeth of concern may be taken as well, and other standard views are discussed below. If performing extractions, both pre- and post-extraction radiographs are vital to confirm your diagnosis, prepare you for what lies beneath the gingiva, ensure no dental material has been left in place, and to be a permanent record of same.

Offset Mandible DV view is excellent to evaluate symmetry of the maxilla and mandible and to examine cheek teeth for sagittal fractures and/or infundibular defects. Try taking a view at 85° rostro-caudal or caudo-rostral (rather than 90°) to the sensor to compensate for tooth angulation. A threemetre rope with loops on each end may be placed around the diastemata between the .03s and the .06s and used to pull the mandible laterally to take a DV view of a single arcade at a time (Fig. 7).

DV view clearly shows sinuses and skull abnormalities, but is of limited value in visualising dentition, due to overlapping of teeth in the opposing arcade.

Oblique views are the most useful views for evaluating everything from incisors, through unerupted wolf teeth, to cheek teeth (Figs.8, 9). They must be labelled appropriately to be of diagnostic use. The apices of maxillary cheek teeth are effectively radiographed in an approximately 30° dorsal to ventral direction, as mentioned in labelling section, above.

If mouth is wide open, ipsilateral mandibular reserve crowns should be visible between the rows of cheek teeth as well.

Eq Vet Pract 2021 March; 46 (1) 21

Mandibular cheek teeth apices are best radiographed in an approximately 50° ventral to dorsal direction. If mouth is wide open, ipsilateral maxillary reserve crowns should be visible between the rows of cheek teeth as well. With both mandibular and maxillary teeth, although we set an angle for these views, remember the angle must be altered based upon the age of the patient. Younger horses have longer apices, which require greater angulation to shoot the whole apex; but be aware that with greater angulation, the apices will be visually shortened.

Figure 7: Displacing the mandible to one side allows a DV view of a single mandibular arcade [Top]. 209 Sagittal fracture and damaged 210 [Bottom] extracted from patient shown in the displaced-DV radiograph.

Incisors and Canines: The best diagnostic radiographs of the rostral teeth are taken by using open-mouthed techniques, both extraoral and intraoral. Intraoral views require placement of the sensor against the occlusal surface of incisors and use of the bisecting angle technique, or approximately 70o to the angle of the sensor. Protection of the delicate sensor is vital; one may place the sensor in a tunnel, use an aluminium speculum or aluminium speculum plates, or employ a tube speculum – the last may limit how far the sensor may be placed in the mouth. Standard views for the canines include open-mouthed laterals and obliques. For the incisors, the DV, VD and open-mouthed obliques offer the most information. For both, take other views to highlight teeth of interest (Fig 10).

Figure 10: Intra-oral views of incisor and canine arcades: DV [A] and VD [B] and oblique [C] views.

7. GET YOURSELF A SKULL Always have an equine skull [cranium and mandible] in the practice vehicle and in the clinic.

Figure 8: Oblique view of caudal arcades highlights apices.

Figure 9: Oblique view of apical infection in a five-year-old grade gelding with mandibular draining tract.

22 Eq Vet Pract 2021, March; 46 (1)

There is nothing like having a reference skull to improve dental radiology techniques and interpretation, as well as for nerve blocks and reviewing sinus surgical approaches. They are useful for locating nerve foramina and landmarks for regional anaesthesia and, just as important, for showing clients what we’re trying to do for their horse. One can draw on it the many nerve block injection sites and cut out portions of the external skull to expose cheek teeth and sinuses. Skulls are also excellent for identifying the orientation of the interdental spaces between cheek teeth, vital when radiographing to detail the extent of crestal bone loss in these locations.

Another plus is that you can use a head or skull to create the radiographic technique chart for your equipment. Wet equine cadaver heads are obtainable from abattoirs or hunt club kennels and a clean skull may be prepared by many methods [contact the author if assistance required for this].

8. THE PORCUPINE TECHNIQUE; Evaluation of Interdental Space Angulation You may find radiographing interdental spaces difficult.

Usually one or two but not all will line up with the beam and clearly show the height of the crestal bone; this is normal.

One quick look at a skull and a few toothpicks will help here.

The interdental spaces are not parallel. While angulation will differ between equids, the skull shown displays the concept to view all spaces (Figs. 11, 12).

Taking radiographs may seem to be a huge challenge, but with a few extra ideas up your sleeve, you can take radiographs that will result in truly diagnostic films that you’re proud to send to any referral colleague, anywhere. Try these tips and see!

BIBLIOGRAPHY Baratt RM. Dental Radiography and Radiographic Signs of Equine Dental Disease. Vet Clin Nth Am – Eq Pract. 2020.

36(3): 445-476. 10.1016/j.cveq.2020.08.001 Baratt RM, Limone LE. Dental Radiology of the Horse. J Vet Dentistry. 2018; 35(1): 37-41. DOI: 10.1177/0898756417736882 Easley J. Every Practitioner Can Take Good Radiographs.

Virginia Vet Med Assoc. 2018. PDF download available HERE

Figure 11: Interdental spaces are not parallel. Here, toothpicks inserted between maxillary teeth display angular variation from the interdental space at the centre of the arcade (between ’08 and ’09), indicating the approximate angulation you need to direct the radiographic beam to view crestal bone height between teeth of concern (i.e. diastemata).

These angles vary between patients.

Easley J, Dixon PM, Schumacher J. Equine Dentistry. 3rd Ed. Elsevier Saunders. Philadelphia, PA.

ACKNOWLEDGEMENTS Gary Wilson and Oliver Liyou for their continued enthusiasm and support; Robert Baratt for his assistance and many excellent papers on Equine Dental Radiology; other members of the NZEVA Dental Subcommittee Glenn Beeman, Katie Kindleysides, Raymond Lenaghan and Marieke van den Enden - for their unstinting efforts to improve veterinary equine dental education in New Zealand.

Figure 12: As with the maxilla, the mandibular cheek teeth display variation in angulation of interdental spaces as depicted by the toothpicks.

Eq Vet Pract 2021 March; 46 (1) 23

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COMMISSIONED REVIEW ARTICLE* ANTIMICROBIAL INTRAVENOUS REGIONAL LIMB PERFUSION: FROM THEORY TO PRACTICE PART 1: PROCEDURE Gal Kelmer Koret School of Veterinary Medicine The Hebrew University of Jerusalem Rehovot, ISRAEL gal.kelmer@mail.huji.ac.il

One of the most common challenges in equine practice is dealing with distal limb trauma resulting in life threatening infection of synovial structures. Intravenous antimicrobial regional limb perfusion (RLP) is a useful technique of treating and preventing such distal limb infections. This modality markedly decreases morbidity and mortality associated with trauma to these regions 1,2. The procedure entails placing a tourniquet proximal to the target area, then injecting diluted antimicrobial solution (perfusate) intravenously to the isolated portion of the limb (Figure 1).

Part 2 of this article will appear in EVP June 2021

As an alternative, the procedure can also be performed by drilling into a bone and injecting into its medullary cavity 3–6.

However, the intra-osseous route does have drawbacks. It entails using specialized orthopaedic equipment, leakage of perfusate is a problem and the procedure is painful 1. Also, the defect created in the bone by the drill, can act a stress riser and lead to catastrophic failure 7 or the antibiotic can cause osteomyelitis and osteonecrosis that may lead to pathologic fracture 8. Due to these disadvantages, the intra-osseous route should be reserved only for situations, where IV access for RLP cannot be gained. Although the RLP technique is well established, there are still gaps in our knowledge about this versatile modality. In recent years, there is a surge of research regarding RLP, with some studies investigating a few of the procedure’s basic concepts, while others investigating innovative directions of therapy.

How it all started: Regional limb perfusion was first described in 1908 by Bier, for regional anaesthesia; to facilitate surgical procedures in human extremities 9. The technique was subsequently studied and used for administration of antimicrobials and anti-cancer drugs, and for some tumours is still one of the most effective anticancer modalities available today 10. In 1990, Dietz and Kehnscherper first described antimicrobial regional perfusion in horses 11. Since then, RLP was thoroughly investigated in horses, and in the past 20 years it became the standard of care both for treating distal limb infections and as a preventative measure in orthopaedic surgery 12.

Figure 1: Forelimb regional limb perfusion using the cephalic vein, for treating chronic foot infection.

The reasoning behind the technique: Traumatic distal limb injuries are common in horses and when these involve synovial structures, it can cause significant morbidity and even lead to mortality 13. To eliminate the pathogenic bacteria, antimicrobial agents need to reach adequate concentration in the injured tissue, including synovial structures.

* These commissioned articles are made possible by a generous grant made to EVP by Jonathan Hope.

Eq Vet Pract 2021 March; 46 (1) 25

Systemic administration of antimicrobials is often inadequate to eliminate the infection due to poor blood supply to the distal portion of the limb and insufficient synovial concentrations 13,14 . During RLP, high concentrations and pressure gradients between the intravascular and extra-vascular compartments are obtained 15,16. This facilitates diffusion of the antimicrobial drug into the surrounding tissues, including the poorly vascularized tissues; where bacteria are protected from systemically circulating antimicrobials 17. Regional application of antibiotics, offers a high local drug concentration at the site of infection while maintaining low systemic drug levels, thereby avoiding possible side effects 18. Any antibiotic used in any systemic route, can cause significant side effects in horses, mainly antibiotic induced diarrhoea that can be fatal 19 . Thus, avoiding the systemic route is highly advantageous in that respect as well.

To what tissues does RLP deliver the antibiotics? Most studies on pharmacokinetics (PK) evaluated the efficacy of the procedure by measuring AB concentration in synovial fluid 16,20–25 . However, synovial sepsis is often secondary to trauma that involves other tissues such as skin, subcutaneous tissue, cartilage and bone. Thus, it is important to know how effective RLP is in delivering the AB into these tissues as well. Several RLP PK studies have measured AB concentrations in bone 6,26–29 and in the subcutaneous tissue 27,28. Regional limb perfusion is currently used extensively, both therapeutically in trauma and prophylactically in orthopaedic surgery. Hence, further RLP PK studies, evaluating concentration of AB in the involved tissues, are needed.

Forelimb versus hindlimb: Most RLP PK studies are performed on the forelimbs since it is safer and easier for the investigators 15,16,20,25,29–46, while there are only several studies evaluating hindlimbs RLP3,21–23,47–50. Thus, many of the RLP parameters and drugs evaluations were actually investigated only on the forelimbs and the information is extrapolated to the hind limbs. When both hind and forelimb were evaluated, RLP using erythromycin into the cephalic vein yielded higher synovial concentration of AB than the saphenous vein23.

Similar results were attained in 2 other studies 22,48. This may be attributed to two potential reasons, one being better tourniquet compression on the tubular uniform shape of the antebrachium compared to the asymmetrical shape of the hind limb proximal to the tarsus. Another potential cause for that discrepancy, is the larger tissue volume in the tarsus compared to the carpus thus diluting the perfusate further in the hindlimb.

Since hind limb injuries necessitating treatment via RLP occur commonly 2,51, there is a need for further investigation into RLP of the equine hindlimbs. Although no difference was found in the rate of complications between fore and hind limbs 47,51, clinically we find that cephalic catheters are faster to cause phlebitis and cellulitis. These catheters should be monitored carefully and removed as soon as possible.

Why strive for high concentrations of antibiotics? The goal of antimicrobial therapy is to achieve antimicrobial concentrations above the MIC in the infected tissue without causing any unwanted systemic or local effects. In human

26 Eq Vet Pract 2021, March; 46 (1)

patients, it was found; that even with time dependant antimicrobials such as beta lactams (e.g. penicillin and cephalosporins), the peak drug concentration (Cmax) is highly important; and provides a useful predictive value.

The goal for Cmax should be 8-10 times higher than the MIC to be efficacious 19,52. These high concentrations of antimicrobials are typically impossible to achieve safely by systemic administration but readily attainable by RLP. MultiDrug-Resistance (MDR) bacteria is an ever-growing problem in human medicine; and in recent years it is becoming a serious threat in equine medicine 53. These high antimicrobial concentrations (>10*MIC) are essential not only for increasing their therapeutic effect, but also to prevent emergence of a population of resistant bacteria 19,52.

Methods of anaesthesia and analgesia: Initially, RLP in the horse was studied and performed under general anaesthesia (GA) 14. Later, it was discovered that sedation can serve as an adequate restraint for the procedure 54. However, if performing the procedure standing, the horse may move and that can lead to leakage of perfusate under the tourniquet and decrease the procedure’s efficacy. Means to prevent this movement include peripheral nerve blocks or adding local anaesthetic to the perfusate. A study by Mahne et al. revealed that adding local anaesthesia (2% lidocaine) to the perfusate did not prevent movement; and peripheral nerve block with lidocaine was just as effective as GA; in preventing movement during the procedure 55. Furthermore, in a recent study by Aristizabal et al., the results actually showed higher synovial concentrations of antimicrobials after standing sedation with regional lidocaine nerve blocks, than after GA 30. In another study, however, mepivacaine added to the perfusate, did not affect amikacin synovial concentrations, and provided effective analgesia 56. Additionally, it was demonstrated that Morphine can reach effective analgesic concentration when administered via IVRLP and it can be effectively combined with gentamicin 57. A recent study found that butorphanol administered via IVRLP can be detected in synovial fluid and provides some analgesia 44. Analgesia was inconsistent and short-lived but increasing both the dose and the volume may yield better results. Thus, sedating the horse for RLP, and using either regional nerve blocks or adding local anaesthetic or an opiate to the perfusate, is both practical and supported by up-to-date research.

Should the limb be exsanguinated? When RLP was first described, exsanguination of the limb was performed prior to injection of the perfusate 9. This was adopted in early equine studies as well 5,29,35. The reasoning behind it, is to decrease antimicrobial dilution in blood, improve penetration of the tissue since the blood vessels are empty and avoiding leakage under the tourniquet by decreasing the intravascular pressure 33. In a study by Sole et al. exsanguinations improve antimicrobial concentration in the fetlock but not in the carpus 33 . Technically, exsanguination is feasible upon introduction of an indwelling catheter; but in the following days, blood flow through the catheter typically declines and ceases.

The concentration of amikacin in the fetlock, reached after

exsanguinations by Sole et al. are not higher, and actually seem lower than those reached in multiple recent studies 21,21,36,38,41,46 . Another, more recent study, using low volume RLP, found exsanguination ineffective in increasing synovial AB concentrations 32. Since exsanguination is technically challenging, and similar, if not better, results can be achieved without it, the current information does not support routine exsanguinations for equine RLP. Which tourniquet to use? According to Levine et al. (2010) a pneumatic tourniquet placed above the carpus is more effective than a rubber tourniquet 46. However, when used above the fetlock in the metacarpal/metatarsal area, an Esmarch bandage (wide rubber tourniquet) was proven more effective than pneumatic tourniquet 20. In several PK studies we performed, using the cephalic/saphenous veins, highly therapeutic concentrations of antimicrobials, were measured in the fetlock, using both types of tourniquets (Esmarch & pneumatic) 21–23,38,48. Future studies comparing the efficacy of a rubber tourniquet to that of a pneumatic tourniquet, placed proximal to the carpus/tarsus, may expand our knowledge base; and provide important and useful clinical information.

Number of tourniquets to use? In most studies and clinical reports of RLP a single tourniquet is placed proximal the area to be perfused 1,2,51,58. Nevertheless, when the target region is proximal such as the carpus, an additional tourniquet placed distal to the target region, will restrict the targeted volume of tissue, and thus may improve the efficacy of the procedure.

Several studies have used 2 tourniquets, one proximal and one distal to the carpus 27,32,39,49,57. Schoonover et al. found that with low volume perfusate, low carpal amikacin concentration was reached. However, amikacin concentration was higher when two tourniquets were used compared to one 32. Nevertheless, multiple studies have demonstrated that, highly therapeutic concentrations of antibiotics can be reached in the carpus, when a single proximal tourniquet is placed 30,31,34,59. Thus, for all practical purposes, RLP can be effectively performed using a single proximal tourniquet.

How long should the Tourniquet stay for? Traditionally, tourniquet was left on the limb for 30 minutes during RLP. Tourniquet application causes discomfort and pain that can lead to movement, loss of vessel sealing by the tourniquet, leakage of perfusate and decreased efficacy of the procedure.

Reducing tourniquet duration will decrease discomfort and improve the efficacy of the perfusion. Recent pharmacokinetic (PK) studies made attempts to establish shorter tourniquet duration to decrease discomfort and increase efficacy of the procedure. Kilcoyne et al. (2016) found no difference in synovial antimicrobial concentrations, between 10- and 30-minutes tourniquet application time 34. An additional study; from the same laboratory; found no significant difference in synovial antimicrobial concentration, between horses having 20 and 30 minutes of tourniquet application during RLP 30.

According to these studies, duration of tourniquet application; can be markedly reduced during RLP, and that would facilitate the procedure and can markedly increase its efficacy. In both studies however, the concentration of amikacin, in the fetlock

joint, was surprisingly low (<62 mcg/mL). When one considers MIC of 16 mcg/mL for susceptible pathogens 60, both studies did not reach the required 10 times the MIC concentration, while multiple other RLP PK studies, reached the required amikacin concentrations 21,36,38,41. A recent study found that 15 minutes tourniquet application time was adequate for reaching maximal synovial concentrations (Cmax) in the distal interphalangeal joint 34 and another RLP PK study, found no increase in synovial concentrations from 15 to 30 minutes of tourniquet application 32. In another current research, 15 minutes was the average time to reach Cmax, but to allow all horses to reach Cmax, 20 minutes were required 59. In a study evaluating amikacin PK in the hindlimb, 20 min was found to be adequate tourniquet application time, for reaching desired, therapeutic concentrations (>10*MIC) in the tarsocrural joint50.

Thus, according to current knowledge, 20 minutes tourniquet application time is recommended for RLP. Actually, some of the research studies performed these days use 20-minute tourniquet application duration, while studying other RLP characteristics 61,62.

Which vein to use and how? Initially and for many years the palmar/plantar digital veins were the main route for IVRLP. Typically, multiple RLP sessions are needed to resolve distal limb infection. Regional limb perfusion can result in leakage, perivascular and vascular irritation and inflammation, leading to swelling at the injection site 43,63. This swelling will make consecutive injections difficult and thus may prevent repeated RLP treatments. Using an indwelling instead of a butterfly catheter, can help ascertaining correct insertion, prevent leakage, and enable repeated use (Figure 2) 56,64.

Figure 2: Hind limb regional limb perfusion, using an indwelling, long term, polyurethane catheter, as a prophylactic measure after performing proximal interphalangeal joint arthrodesis, to treat a displaced P2 fracture.

Eq Vet Pract 2021 March; 46 (1) 27

Previously it had been shown that the use of the cephalic and saphenous veins in RLP is at least as efficient and effective as the use of the palmar digital vein 21,23. The cephalic or saphenous veins are easily accessible and of larger diameter and thus are more amenable for indwelling catheters 47.

Furthermore, using a vein proximal to the carpus or tarsus, is useful when the distal limb suffers from trauma; since it allows for immobilization of the region with a cast when indicated (Figure 3)51.

peak level (Cmax) can play an important role and render them useful for once a day therapy 19,39,52. In certain cases, such as with imipenem, a marked post-antibiotic-effect can negate the rapid decrease in concentration 48. To summarize, in general, once a day RLP is practical, effective, and well supported by current research and clinical literature.

How many perfusions to perform? As a prophylactic measure a single perfusion is appropriate and when the concept of treating septic joints with RLP was first tested in horses, a single perfusion proved effective while systemic use was not 14. In some clinical cases a single perfusion indeed resolved the infection67. However, in most instances, in the clinical setting, one is not treating a freshly inoculated joint.

Treatment is often aimed at injuries that may be several days old or more; and multiple tissues are typically involved. Thus, the common duration of RLP therapy for a severe synovial injury, is 7-10 days; and in certain persistent infections it can continue for several weeks2,51.

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Figure 3: Using saphenous regional limb perfusion, proximal to a short limb cast.

Recently, most RLP studies are using the cephalic vein, and it appears that using the proximal vein; is the preferred site for catheter placement 30,33,34,37,40,45. Clinical experience suggests that polyurethane long-term catheters are ideal for use as indwelling catheters for repeated IVRLP 51. A cutaneous analgesic block may be helpful in selected cases where that horse reacts badly to initiation of catheter placement.

What is the recommended frequency of RLP therapy?

When RLP is used clinically, it is typically performed daily 2,51,65 . Also, according to the PK of concentration dependent drugs, such as amikacin, RLP should be performed every 24 hours 21. Initially, RLP was not routinely performed once a day and some clinicians are still performing RLP once every other day. In some cases, this regimen will gain positive results. However, according to both clinical experience and PK data, including post antibiotic effects, the recommended frequency for achieving optimal results, is once a day. When time dependent antibiotics, such as imipenem, metronidazole, ceftiofur and ceftazidime are used, performing RLP several times a day make pharmacokinetic rational 25,37,39,48,66. However, since performing RLP requires heavy sedation, repeating RLP several times a day is impractical. It carries too much risk for creating gastrointestinal disturbances. Also, it was demonstrated, that even in time dependent antibiotic, the 28 Eq Vet Pract 2021, March; 46 (1)

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J Vet Pharmacol Ther 22, 68–71 (1999).

Aristizabal, F. A. et al. Comparison of two tourniquet application times for regional intravenous limb perfusions with amikacin in sedated or anesthetized horses. The Veterinary Journal 208, 50–54 (2016).

Harvey, A., Kilcoyne, I., Byrne, B. A. & Nieto, J. Effect of Dose on Intra-Articular Amikacin Sulfate Concentrations Following Intravenous Regional Limb Perfusion in Horses.

Vet Surg 45, 1077–1082 (2016).

Schoonover, M. J., Moser, D. K., Young, J. M., Payton, M. E. & Holbrook, T. C. Effects of tourniquet number and exsanguination on amikacin concentrations in the radiocarpal and distal interphalangeal joints after low volume intravenous regional limb perfusion in horses. Vet Surg 46, 675–682 (2017).

Sole, A., Nieto, J. E., Aristizabal, F. A. & Snyder, J. R. Effect of emptying the vasculature before performing regional limb perfusion with amikacin in horses. Equine Vet J 48, 737–740 (2016).

Kilcoyne, I., Dechant, J. E. & Nieto, J. E. Evaluation of 10-minute versus 30-minute tourniquet time for intravenous regional limb perfusion with amikacin sulfate in standing sedated horses. Vet Rec 178, 585 (2016).

Rubio-Martínez, L. M. et al. Evaluation of safety and pharmacokinetics of vancomycin after intravenous regional limb perfusion in horses. American Journal of Veterinary Research 66, 2107–2113 (2005).

Dahan, R. et al. Pharmacokinetics of regional limb perfusion using a combination of amikacin and penicillin in standing horses. Can Vet J 60, 294–299 (2019).

Oreff, G. L. et al. Pharmacokinetics of ceftazidime after regional limb perfusion in standing horses. Veterinary Surgery 46, 1120–1125 (2017).

Oreff, G. L. et al. The Effect of Perfusate Volume on Amikacin Concentration in the Metacarpophalangeal Joint Following Cephalic Regional Limb Perfusion in Standing Horses. Veterinary Surgery 45, 625–630 (2016).

Pille, F. et al. Synovial Fluid and Plasma Concentrations of Ceftiofur After Regional Intravenous Perfusion in the Horse.

Veterinary Surgery 34, 610–617 (2005).

Zantingh, A. J., Schwark, W. S., Fubini, S. L. & Watts, A. E. Accumulation of amikacin in synovial fluid after regional limb perfusion of amikacin sulfate alone and in combination with ticarcillin/clavulanate in horses. Vet Surg 43, 282–288 (2014).

Errico, J. A., Trumble, T. N., Bueno, A. C. D., Davis, J. L. & Brown, M. P. Comparison of two indirect techniques for local delivery of a high dose of an antimicrobial in the distal portion of forelimbs of horses. Am J Vet Res 69, 334–342 (2008).

Hunter, B. G., Duesterdieck-Zellmer, K. F. & Larson, M. K. Tiludronate concentrations and cytologic findings in synovial fluid after intravenous regional limb perfusion with tiludronate in horses. PeerJ 3, e889 (2015).

Lallemand, E. et al. Pharmacokinetics, Pharmacodynamics and Local Tolerance at Injection Site of Marbofloxacin Administered by Regional Intravenous Limb Perfusion in Standing Horses. Veterinary Surgery 42, 649–657 (2013).

Crabtree, N. E. et al. Synovial butorphanol concentrations and mechanical nociceptive thresholds after intravenous regional limb perfusion in standing sedated horses.

Veterinary Surgery 48, 1473–1482 (2019).

Eq Vet Pract 2021 March; 46 (1) 29

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Beccar‐Varela, A. M., Epstein, K. L. & White, C. L. Effect of Experimentally Induced Synovitis on Amikacin Concentrations after Intravenous Regional Limb Perfusion. Veterinary Surgery 40, 891–897 (2011).

Levine, D. G., Epstein, K. L., Ahern, B. J. & Richardson, D. W. Efficacy of Three Tourniquet Types for Intravenous Antimicrobial Regional Limb Perfusion in Standing Horses.

Veterinary Surgery 39, 1021–1024 (2010).

Kelmer, G., Elliot, S. B., Catasus, C. T. & Saxton, A. M. Evaluation of indwelling intravenous catheters for the regional perfusion of the limbs of horses. Veterinary Record 165, 496–501 (2009).

Kelmer, G., Tatz, A. J., Kdoshim, E., Britzi, M. & Segev, G. Evaluation of the pharmacokinetics of imipenem following regional limb perfusion using the saphenous and the cephalic veins in standing horses. Res Vet Sci 114, 64–68 (2017).

Snowden, R. T. et al. Tarsocrural joint polymyxin B concentrations achieved following intravenous regional limb perfusion of the drug via a saphenous vein to healthy standing horses. American Journal of Veterinary Research 80, 1099–1106 (2019).

Kilcoyne, I., Nieto, J. E., Galuppo, L. D. & Dechant, J. E. Time required to achieve maximum amikacin concentration in the synovial fluid of the tarsocrural joint following administration of the drug by intravenous regional limb perfusion in horses.

Am J Vet Res 82, 99–104 (2021).

Kelmer, G., Tatz, A. & Bdolah‐Abram, T. Indwelling Cephalic or Saphenous Vein Catheter Use for Regional Limb Perfusion in 44 Horses with Synovial Injury Involving the Distal Aspect of the Limb. Veterinary Surgery 41, 938–943 (2012).

McKellar, Q. A., Sanchez Bruni, S. F. & Jones, D. G. Pharmacokinetic/pharmacodynamic relationships of antimicrobial drugs used in veterinary medicine. J Vet Pharmacol Ther 27, 503–514 (2004).

Walther, B., Friedrich, A. W., Brunnberg, L., Wieler, L. H. & Lübke-Becker, A. [Methicillin-resistant Staphylococcus aureus (MRSA) in veterinary medicine: a ‘new emerging pathogen’?].

Berl Munch Tierarztl Wochenschr 119, 222–232 (2006).

Palmer, S. E. & Hogan, P. M. How to Perform Regional Limb Perfusion in the Standing Horse. 4 (1999).

Mahne, A. T., Rioja, E., Marais, H. J., Villarino, N. F. & Rubio-Martinez, L. M. Clinical and pharmacokinetic effects of regional or general anaesthesia on intravenous regional limb perfusion with amikacin in horses. Equine Vet J 46, 375–379 (2014).

Colbath, A. C., Wittenburg, L. A., Gold, J. R., McIlwraith, C. W. & Moorman, V. J. The Effects of Mepivacaine Hydrochloride on Antimicrobial Activity and Mechanical Nociceptive Threshold During Amikacin Sulfate Regional Limb Perfusion in the Horse. Veterinary Surgery 45, 798–803 (2016).

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Kelmer, G. Regional limb perfusion in horses. Vet Rec 178, 581–584 (2016).

Gustafsson, K. et al. Time to Peak Concentration of Amikacin in the Antebrachiocarpal Joint Following Cephalic Intravenous Regional Limb Perfusion in Standing Horses. Vet Comp Orthop Traumatol 33, 327–332 (2020).

Prescott, J. F. & Baggot, J. D. Antimicrobial susceptibility testing and antimicrobial drug dosage. J Am Vet Med Assoc 187, 363–368 (1985).

Edwards-Milewski, M. L., Morello, S. L., Zhao, Q. & MattanBell, C. The Effect of Intravenous Regional Perfusion of the Distal Limb With Amikacin Sulfate on Wounds Healing by Second Intention in Horses. Vet Surg 45, 125–132 (2016).

Freeland, R. B., Morello, S. L., DeLombaert, M. & Rajamanickam, V. Influence of intravenous regional limb perfusion with amikacin sulfate on Staphylococcus aureus bioburden in distal limb wounds in horses. Vet Surg 46, 663–674 (2017).

Levine, D. G., Epstein, K. L., Neelis, D. A. & Ross, M. W. Effect of topical application of 1% diclofenac sodium liposomal cream on inflammation in healthy horses undergoing intravenous regional limb perfusion with amikacin sulfate.

American Journal of Veterinary Research 70, 1323–1325 (2009).

Hyde, R. M., Lynch, T. M., Clark, C. K., Slone, D. E. & Hughes, F. E. The influence of perfusate volume on antimicrobial concentration in synovial fluid following intravenous regional limb perfusion in the standing horse. Can Vet J 54, 363–367 (2013).

Orsini, J. A. Update on Managing Serious Wound Infections in Horses: Wounds Involving Bone. Journal of Equine Veterinary Science 55, 123–138 (2017).

Gustafsson, K. et al. The concentration of metronidazole in the distal interphalangeal joint following intravenous regional limb perfusion via the cephalic vein in standing horses.

Veterinary Comparative Orthopaedics and Traumatology Accepted for Publication, (2021).

Cimetti, L. J., Merriam, J. G. & D’Oench, S. N. How to Perform Intravenous Regional Limb Perfusion Using Amikacin and DMSO. Ptoc 50th Ann Conv AAEP. 2004; P1429.1204. https:// www.ssequineclinic.com/wp-content/uploads/2018/08/ articles_IRLP.pdf

WHAT IS REQUIRED TO SET UP FOR A DISTAL LIMB INTRAVENOUS REGIONAL LIMB PERFUSION? Make a list of all items then turn to page 56 for a recommended list and a brief description of the procedure.

Also see page 25 for Part one of two papers on Antimicrobial Intravenous Regional Limb Perfusion - From Theory to Practice by Gal Kelmer.

30 Eq Vet Pract 2021, March; 46 (1)

ALEX PEARCE ONE OF OUR MORE FREQUENT FRONT COVER PHOTOGRAPHERS Alex Pearce with her Alexandra Tresta Creative Studio is fortunate to be in one of the most stunning regions of New Zealand. Living in Ruapehu on a 400-hectare sheep and beef farm reignited her passion for photography with EVP cover images being prime examples of her photographic skills. She is proud to help share the farming story with the world, and in a time when it has never been quite so crucial.

With a love for capturing moments in life that need to be shared it is no wonder that much of Alex’s work revolves around events, having photographed a wide variety from equestrian sport to rural weddings. Furthermore, she also offers commercial product shoots for aligned businesses with content creation for use in digital marketing to promote businesses and to spark customer interest.

Services offered through Alexandra Tresta Creative Studio include photography, branding, digital marketing and content creation; please get in touch.

Alex Pearce | 027 256 6484 alextpearce@outlook.com

WE’RE HERE TO HELP CONTACT US TODAY (07) 888 8193

• 24/7 Emergency Referral Hospital • Full Reproductive Service • Performance and Sports Medicine • Sales and Yearling Consultancy and Radiology

ADVANCING VETERINARY SCIENCE IN THE HEART OF THE WAIKATO Our dedicated team of highly experienced Equine Veterinarians provide the latest diagnostics, treatment and best care available for your horse.

• Pre-purchase Examinations – including Hong Kong • Digital Radiography • Ultrasonography • Scintigraphy (Bone Scan) • Shockwave Therapy Dave Keenan BVSc MANZCVS Andrea Ritmeester BVSc (Hons) MS DipACVS Leigh de Clifford BVSc CertAVP PGDipVPS MVSc Barbara Hunter DVM MS DAVCS-LA

362 Hinuera Road West Matamata (07) 888 8193 matamatavets.co.nz

Eq Vet Pract 2021 March; 46 (1) 31

Image credit Uni Melbourne

EQUINE CONFERENCES, SEMINARS & WORKSHOPS FROM MARCH 2021 CHECK WEBSITES FOR COVID-UPDATES

Image credit: TheHorse

• To access further details for the following, CTRL-CLICK on hyperlink or insert name and location of event into your search engine.

• Listed events are delivered in English • For additional events see http://www.ivis.org/home.asp • Aware of an upcoming equine event? Please inform the editor evp.editor@gmail.com

It looks like most overseas conferences for the foreseeable future will be cancelled or will be virtual. We have thus put only a short collection of details for a few of the major meetings. Keep tabs on the web sites for updated information.

Note that many organisers now have reduced registration fees for access to recorded conference presentations, that are available for an extended period after the actual conference, and good value in our opinion. And some of them even keep track of what you have watched, so you can easily and painlessly claim for CPD!

2021 MARCH March: 20-21

Advanced mare reproduction wetlab. Matamata Vet Services Equine Hospital – TBC at later date.

MAY May 16-21

AVA Annual Conference. Sydney, AUS

JUNE June 5-9

Veterinary Meeting & Expo (VMX; formally NAVC). Orlando, FL. USA. VIRTUAL

June 9-12

American College of Veterinary Internal Medicine. ACVIM Virtual Forum. USA.

June 23-25

NZVA/NZEVA [Equine Vets & Nurses] Conference. Wigram Museum, Christchurch

June 25-26

NZEVA/VetPD Workshop. Canterbury Equine Clinic. Prebbleton, Christchurch

JULY July 8-10

European College of Veterinary Surgeons Annual Scientific Meeting. Antwerp, Belgium

July 14-16

International Equine Colic Research Symposium, Edinburgh, UK.

SEPTEMBER September 4-7

BEVA Annual Congress, Birmingham 2021. UK

September 11-15

International Veterinary Emergency & Critical Care Symposium. Nashville, USA

DECEMBER December 4-8

32 Eq Vet Pract 2021, March; 46 (1)

AAEP Annual Convention. Nashville, TN. United States

OBITUARY (PAT) STUART PATRICK BROOKS On the evening of 30th December Pat went out for his usual garden possum patrol. He did not return and Jendy, led by the barking of their faithful dog, found Pat lying in the garden, the victim of a cardiac arrest. Pat was 71 years old.

His funeral notice in the paper read:

Brooks, Stuart Patrick (Pat).

Unexpectedly at home at French farm, Banks Peninsula on December the 30th 2020.

Much loved husband of Jen, father of Emma, Sam, Fran and Pip. Brother of Ian, father-in-law of Rhys, Hannah, Mike and Simon. Worshipped grandfather and handy vet to many.

A gathering to share love, laughter and stories will be held at 104 French Farm Valley Rd on Friday January 8th at 11:00 AM. “He will be peeved off when he finds out about this”.

That pretty much gives you a synopsis of Pat right there: Understatement and dry wit.

I think he would have been proud to have written that notice himself. He loved his family and was especially doted on by his grandchildren who loved his humour, his sense of mischief and his eccentricity.

I knew Pat for over 50 years and every time we met, I learned a little more about him and from him, but you always had the feeling that to some degree you were just scratching the surface.

He was a private man and would often have a wee smile on his face or even that characteristic grin with just his eyes, as if he was enjoying a private joke with himself.

Pat was a man of many skills. He started in general practice in Invercargill, before travelling overseas to the UK and South Africa with Jendy, did practice in Christchurch and was a keen early deer veterinarian in Te Anua back in the days when deer were captured in nets by cowboys riding helicopters. It was no place for the fainthearted.

He then moved to Oamaru and became a practice owner, a country mixed practice veterinarian, an expert in embryo transfer and later excelled as a horse vet.

I think horses were his real love, he enjoyed the camaraderie and sense of community in harness racing especially and we would often have discussions on challenging and unusual cases. He loved veterinary practice and was always wanting to extend his knowledge.

He took great delight in passing on his experience, his knowledge, and his skills, although it would be fair to say that he lamented the fact that most new veterinarians nowadays graduate already ‘knowing everything’. One area where he quietly and very effectively worked away was his mentoring of fellow veterinarians, in particular overseas arrivals who struggled initially with language difficulties and with the nuances of kiwi clients. He was always ready to support and assist them at any hour.

Pat started practice in an environment and a time where you learned by experience, by making mistakes, by having great colleagues who were happy to mentor you and having grateful and gracious clients and farmers who were happy for you to give it a go and do the best you could, no matter what the outcome.

Pat relished this and right up until his death he maintained those same principles. He was still in active practice enjoying his work, mentoring others and being what he always wanted to be…. a fine veterinarian.

Bill Bishop 25.01.21

Eq Vet Pract 2021 March; 46 (1) 33

VETLOGIC PUZZLE - EVP MARCH 2021

4. The four anglers were Emma Gordon, the one who caught the kingfish, and those who caught the largest two fish.

Can you work out on the fillable grids below who caught which fish and the length of each fish?

ANGLER

LENGTH (m)

3. Of the anglers landing the biggest fish and Lucy Russell, neither caught a kingfish or a bluefin tuna.

2 3 4 BLUEFIN TUNA KINGFISH MARLIN SWORDFISH

FISH

See page 55 for answers

LENGTH

EMMA GORDON TRISH PEARCE LUCY RUSSELL RABECCA MCKENZIE

A PRIMER ON CURRENT UNDERSTANDING OF EQUINE ASTHMA Available HERE is a discussion by Laurent L. Couëtil and Jean-Pierre Lavoie from THE HORSE and compiled by Stacey Oke. This short outline of the disease covers definition, pathophysiology, diagnosis, prevention and therapy. It has been sponsored by Boehringer Ingelheim, makers of Alvesco™, containing ciclesonide a newly released inhalation glucocorticoid for treatment of severe equine asthma using an equine-designed nebuliser.

34 Eq Vet Pract 2021, March; 46 (1)

SWORDFISH

MARLIN

BLUEFIN TUNA

RABECCA MCKENZIE

FISH

1

FISH

2. Lucy Russell caught either the swordfish or the shortest fish.

LUCY RUSSELL

1. The bluefin tuna was 2m shorter than Trish Pearce’s fish.

TRISH PEARCE

EMMA GORDON

ANGLER

KINGFISH

Four of our EVP Editorial Board colleagues entered in the Gisborne Ladies Sportfishing Contest and related to the EVP their stories about the largest fish they caught:.

MEDICINE CORNER WHEN GOOD JUGULARS GO BAD Emma Gordon E.Gordon1@massey.ac.nz Image: blogspot

Jugular vein thrombophlebitis is one of the more common (and frustrating/disappointing!) complications in sick hospitalized patients with in-dwelling catheters, however, can also occur following a single intravenous injection in the field.

Phlebitis is a term that refers to inflammation of a vein, whereas thrombophlebitis indicates additional presence of an intravascular blood clot associated with the inflamed vessel wall. Thrombophlebitis can be septic (associated with bacterial infection), or aseptic (inflammation without infection). Typical clinical signs that should raise concern for thrombophlebitis include localized signs of swelling at or around the catheter insertion site, pain or heat on palpation of the vein and discharge from the insertion site (Dolente et al. 2005). Prior to these signs, it may have been observed that the catheter is becoming difficult to flush or can be flushed but will not aspirate blood. The vein itself may be slow to fill as well. With some experience, a thickening or ‘ropeyness’ of the vessel below the catheter insertion site may be appreciated prior to more obvious signs developing (Schoster 2017). It should be easy to palpate the catheter within the vessel in a normal vein, but vein thickening will make this more challenging, which should be indication for concern. When a thrombus occludes the majority or entirety of the jugular lumen, distention of the vein above the catheter site will be observed, and the head may be quite swollen, sometimes with distension of the small vessels of the face as well.

The more severe cases of thrombophlebitis (especially when infection is present), may present with associated systemic signs as well, including fever, lethargy, dullness, or pain on moving their neck (Dolente et al, 2005). Bloodwork may show either leucopoenia or leucocytosis depending on disease stage, elevated plasma fibrinogen and serum amyloid-A, elevated globulins and possibly anaemia (Dias et al, 2013; Dolente et al, 2005).

DIAGNOSIS Confirmation of thrombophlebitis is made based on presence of compatible clinical signs, and ultrasonographic examination. Determining whether infection is present can be more difficult, as many of the presenting signs can be present simply with inflammation. Presence of fever, white cell count abnormalities, and fluid pockets on ultrasound are more likely to indicate infection, however this is not an absolute distinction. Culture of a microbial pathogen is possible in some cases. When removing a catheter from a vein that

may be infected, a sterile preparation should be performed around the insertion site, then the tip of the catheter should be snipped off and placed into a red top vacutainer for submission to attempt culture. Bacteria can be cultured from the catheter tip of thrombophlebitis cases in up to 50-60% of cases (Schoster 2017). Discharge from the site may also yield useful positive culture results. If there is no catheter to remove, a blood culture sample may be obtained from distal to the site of suspected vascular inflammation.

ULTRASOUND Ultrasound is an excellent tool for evaluating the vessels in question [Figure 1 ] (Pasolini et al., 2019) and for diagnosis of thrombophlebitis and for evaluating onset, severity and monitoring of progression or response to treatment [Figures 2 and 3] (Dias et al, 2013; Dufourni et al. 2019). A linear tendon probe tends to work best (7.5-12mHz), with the hair clipped and coupling gel applied, although methylated spirits or isopropyl alcohol is often sufficient. A well cleaned rectal probe will also be adequate in many cases, if that is all that is available (Bain 2013).

The vein should be occluded distally to distend the lumen for ultrasound examination [Figure 1], although this will be ineffective if a thrombus is causing complete obstruction of blood flow. Contact pressure takes some practice, as it is easy to press too firmly with the probe, collapsing the vessel thus making interpretation difficult. The vein should be evaluated both in transverse/cross sectional and longitudinal views [Figures 1 and 2].

Ultrasound will allow for evaluation of the vessel wall for thickening, the perivascular tissues, and the vessel lumen for presence of a thrombus [Figures 2 and 3]. When a thrombus is present, the degree of lumen obstruction can be evaluated, and the length of thrombus measured for monitoring purposes.

Mural and perivascular tissues can also be evaluated for the presence of fluid pockets that may allow sampling for culture, and for evidence of infection such as hyperechoic regions and for gas shadowing within the thrombus that can indicate presence of anaerobic infectious bacteria (Bain 2013).

TREATMENT The first 24 hours is thought to be the most effective time to intervene (Dias et al, 2013). When jugular vein phlebitis/ thrombophlebitis is suspected, any catheter should be removed immediately and not replaced into that vein. Warm Eq Vet Pract 2021 March; 46 (1) 35

Figure 1. A: Ultrasound image of a normal jugular vein in longitudinal view that has been occluded by digital pressure distal to the image. Note how distinct the vessel walls are.

B: Cross sectional ultrasound image of a normal jugular vein. The clinician is not adequately occluding the vessel distal to the ultrasound probe, therefore the vein has a collapsed, irregular margin. Quality of information can be significantly improved by fully distending the vein during scanning.

C: Ultrasound image of a normal jugular vein in longitudinal view, with a 14 g catheter in place.

Figure 2. A: Cross sectional ultrasound image [A] just distal to the catheter site 36 hours after catheter insertion in a foal. A small thrombus can be seen adhering to the dorsal wall of the jugular vein [arrow]. The surrounding material [star] is swirling blood from occluding the jugular vein during imaging. Image courtesy of Dr. Alaina Tessier.

B: Longitudinal view of same site as Fig 2A. The thrombus can be visualised and measured for monitoring purposes. Image courtesy of Dr. Alaina Tessier.

Figure 3. A: Cross sectional ultrasound image of a jugular vein in a horse with catheter-induced thrombophlebitis, showing a completely occluded jugular vein filled with thrombus [oval], with significant perivascular cellulitis present [arrow]. Image courtesy of Dr. Jennifer Neiss Melcher.

B: Cross sectional ultrasound image of a jugular with thrombophlebitis, showing lumen partially occluded by thrombus and fibrin.

Photo courtesy of Dr. Leah Starr Hamilton.

C: Cross sectional image of a jugular vein with perivascular inflammation. This horse received perivascular detomidine several days prior. The vessel itself appears unaffected, however there is inflammation within the surrounding tissues, which is distorting the wall of the jugular vein. The carotid artery can be seen below.

36 Eq Vet Pract 2021, March; 46 (1)

compresses might be helpful, as may topical anti-inflammatory medications such as diclofenac sodium or DMSO (Dias et al, 2013; Smith et al, 2015). Systemic anti-inflammatory medications are indicated. Aspirin can be administered at 10-20 mg/kg by mouth every 24-48hours, however it is unknown if this is truly effective. Unlike in humans, aspirin does not appear to change platelet aggregation, although it does decrease thromboxane B2 (Broome et al, 2013).

Heparin sodium can be used at 30-40 units/kg SC every 12 hours and may be helpful in preventing extension of an existing thrombus but is unlikely to cause resolution of what has already formed (Smith et al, 2015). Aspirin or heparin therapy could be considered in high risk patients (i.e. sepsis, endotoxaemia) prior to occurrence of vein concerns, to reduce likelihood of a thrombus developing (Smith et al, 2015). In particular, low molecular weight heparin (Dalteparin) at 50 IU/KG SC q 12-24 hours has been found to decrease the incidence of jugular thrombosis compared to unfractionated heparin, in horses undergoing colic surgery (Diaz et al, 2013).

Broad spectrum antimicrobial drugs should be used if septic thrombophlebitis is suspected, or if ultrasound shows a cavitated thrombus (Smith et al, 2015). In very rare cases, fungal infection is documented (Dias et el, 2013). When anaerobic infection is suspected, based on ultrasound findings of hyperechoic pockets with gas shadows, metronidazole is indicated (Dias et al, 2013). In severe cases of complete occlusion, surgical resection of the affected portion of vein, as well as surgical thrombectomy have been performed successfully. Clopidogrel (4mg/kg loading dose then 2mg/kg by mouth once daily) has been shown to effectively decrease platelet aggregation in horses and appears to be more effective at this than aspirin (Brainard et al, 2011). Response to clopidogrel appears to vary significantly between horses.

Additionally, presence of endotoxaemia appears to reduce or eliminate the effectiveness of clopidogrel on decreasing platelet aggregation (Watts et al, 2014).

Warfarin therapy has been reported to be successfully utilized in resolving thrombophlebitis, however, is not recommended for routine use and must be accompanied by close monitoring of pro-thrombin time (Dias et al, 2013). Direct local infusion of tissue plasminogen activator is a potential treatment, however, is not without risk and is not performed routinely.

RISK FACTORS Jugular vein thrombophlebitis is more likely to occur when certain risk factors are present, therefore owners can be warned. Presence of a catheter, especially for multiple days, is the most obvious risk factor. The longer the catheter is in place, the higher the risk in general. Presence of endotoxaemia or systemic inflammatory response syndrome [SIRS] increases the odds of developing thrombophlebitis, as does presence of large intestine inflammatory disease, and the specific diagnosis of Salmonellosis (Dolente et al, 2005).

In general, diseases contributing to a hypercoagulable state including colitis, severe pleuropneumonia and neoplasia, are more likely to be associated with development of this

complication. Dolente (2005) also found administration of anti-ulcer medication and presence of hypoproteinaemia to be risk factors, however this likely represents the underlying primary disease.

Catheter material (polyurethane) and length (shorter), type of fluid being administered (glucose, calcium, phenylbutazone, oxytetracycline and parenteral nutrition in particular), and catheter placement technique have all been reported to contribute to increased risk, however other studies have not found these associations to increase the risk of thrombophlebitis (Dolente et al, 2005; Schoster 2017).

It is also important to recognize that even in the absence of obvious risk factors, this complication can occur. A recent yearling presented to Massey following underwent a single intravenous sedation administration for dental work, and then presented for thrombophlebitis and endocarditis several weeks later. Bacteraemia during dental prophylaxis is hypothesized to have contributed in this extremely unlucky (and uncommon!) case. Kern et al (2017) demonstrated that transient bacteraemia of oral origin does commonly occur during tooth extraction in horses, though this yearling did not have an extraction performed. Contamination of a multi-use drug bottle should also be considered in this situation.

RISK REDUCTION While the risk cannot be eliminated entirely, as underlying disease process contributes greatly, some steps can be taken to reduce the risk of thrombophlebitis occurring.

For patients at higher risk, catheter selection should be considered. The least thrombogenic are silastic catheters (Dolente et al, 2005). Thus, the over-the-wire catheters are preferred by many clinicians for use in foals, and for colitis, pleuropneumonia and any severely inflammatory case. These catheters can be purchased impregnated with antimicrobial drugs; however, this tends to make them even more cost prohibitive. Additionally, rigid catheters tend to cause more irritation to the vessel wall than flexible over-the-wire catheters (Schoster 2017). Appropriate rough followed by sterile preparation of clipped skin and use of sterile gloves reduces risks. Chlorhexidine is the recommended product for skin preparation (Norwood et al, 2005), although Dias et al (2013) suggests neither povidone-iodine nor chlorhexidine to be superior to the other. Catheters should be firmly fixed with suture to reduce their movement in and out of the vein (Norwood et al, 2005). Ensuring that local anaesthetic from multidose vials is kept sterile for use when desensitizing catheter sites is essential.

Wrapping of catheters can be argued both to increase risk by preventing frequent assessment, and to reduce risk by reducing contamination. I personally wrap foal catheters and in cases that lie down with frequency. Tubigrip® (a stretchy tube material) works nicely to cover foal catheters instead of sticky elastic, as it can be easily moved to allow frequent vein evaluation. Close monitoring of all catheters with clean gloves multiple times a day is important, and all staff should be trained in this. Checking connections are tight Eq Vet Pract 2021 March; 46 (1) 37

is also important both to reduce entry for infection as well as to reduce risk of disconnection and air embolism. Injection ports should be capped between use, and regular flushing with heparinized saline to reduce clot formation should occur. Wiping an injection port with a commercial alcohol swab prior to injection is done by some clinicians (Schoster 2017). Removing catheters at the first sign of concerning changes to the jugular vein is important. Veins can continue to deteriorate following removal of the catheter. Therefore, it is prudent to NOT place a catheter in a second jugular vein due to risk for life-threatening bilateral thrombophlebitis if the second vein becomes affected, although some clinicians do not share this concern and will use both jugular veins for catheter placement. Alternate sites for catheter placement include the lateral thoracic, cephalic and saphenous veins (Dias et al, 2013; Schoster 2017). When injecting irritant drugs (e.g. oxytetracycline) directly into the vein Diaz et al, 2013) consideration should be given to placing a short-term catheter instead. Routine monitoring via ultrasound of indwelling catheters, particularly longer-term ones, might be prudent to detect early changes not yet evident on clinical evaluation, therefore allowing prompt catheter removal in order to avoid further development of thrombophlebitis (Durourni et al, 2021).

PROGNOSIS If caught early and treated appropriately, most cases of thrombophlebitis will resolve and have no lasting effects.

More severely affected veins may recanalize or can remain non-patent and collateral circulation may develop.

Uncommonly, secondary complications can occur including bacteraemia, septicaemia, thromboemboli to organs such as pulmonary artery or kidneys, bacterial endocarditis, or infarctive pneumonia (Schoster 2017). One study did report that Standardbreds with jugular vein thrombophlebitis have a reduced likelihood of return to racing (Dias et al, 2013).

REFERENCES Bain F. How to Perform Ultrasound Evaluation of the Jugular Vein.

AAEP Proceedings. 2013; 59: 203-208.

Brainard BM, Epstein KL, LoBato D et al. Effects of clopidogrel and aspirin on platelet aggregation, thromboxane production, and serotonin secretion in horses. J Vet Intern Med. 2011; 25 (1): 116-22.

Broome TA, Brown MP, Gronwall RR et al. Pharmacokinetics and plasma concentrations of acetylsalicylic acid after intravenous, rectal and intragastric administration to horses. Can J Vet Res. 2003; 67(4): 297-302.

Dias DPM, de Lacerda Neto JC. Jugular thrombophlebitis in horses: A review of fibrinolysis, thrombus formation, and clinical management. Can J Vet Res. 2013; 54 1: 65-71.

Dufourni A et al. Ultrasonographic assessment of early subclinical cathether-related changes of the jugular vein in hospitalized horses.

12th Congress Europ Coll Eq Int Med. 2019.

Dolente BA, Beech J, Lindborg S, Smith G. Evaluation of risk factors for development of catheter-associated jugular thrombophlebitis in horses: 50 cases (1993–1998). JAVMA. 2005; 227 (7): 1134-1141.

Kern I, Bartmen CP, Verspohl J, Rohde J, Bienert-Zeit A. Bacteraemia before, during and after tooth extraction in horses in the absence of antimicrobial administration. Eq Vet J. 2017; 49 (2): 178-182.

Norwood S, McAuley CE. Vascular catheter-related infections. In: Textbook of Critical Care. Fink Mp, Abraham E, Vincent J-L et al. Eds. Elsevier Saunders, Philadelphia, PA. 2005: 1239-1248.

Pasolini MP, Spinella G, Del Prete C et al. Ultrasonographic assessment of normal jugular veins in Standardbred horses. BMC Vet Res. 2019; 15: 343. https://www.ncbi.nlm.nih.gov/pmc/articles/ PMC6794831/ Schoster A. Complications of intravenous catheterization in horses.

Schweiz Arch für Tierheilkunde. 2017; 9: 477-485.

Reef VB, McGuirk SM. Diseases of the cardiovascular system.

In: Large Animal Internal Medicine. Smith, BP Ed. 5th ed. Elsevier Saunders, Philadelphia, PA. 2015: 454.

Watts AE. Effects of clopidogrel on horses with experimentally induced endotoxemia. Am J Vet Res. 2014; 75: 760.

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USEFUL LINKS We thought you might appreciate having a listing of useful URL links to allied contact groups in your E-EVP - so here is a start.

Please contact us to add or change any address.

AAEP - American Association of Equine Practitioners

ANZCVS - Australian & NZ College of Veterinary Scientists

ARVS - Association of Racecourse Veterinary Surgeons

BAEDT - British Association of Equine Dental Technicians

BHS - The British Horse Society

BEVA - British Equine Veterinary Association

HBLB - Racehorse Health

VETERINARY CLINIC

EQUINE

Massey Equine Veterinary Clinic NZERF - NZ Equine Research Foundation

NZEVA - NZ Equine Veterinary Association NZVA - NZ Veterinary Association SPCA – Society for the Prevention of Cruelty to Animals-NZ Thoroughbred RACEHORSE OWNERS Federation

ESNZ - Equestrian Sports NZ

EVA - Equine Veterinarians Australia

EVJ - Equine Veterinary Journal

FEI - International Equestrian Federation

NZTR - NZ Thoroughbred Racing RCVS - Royal College of Veterinary Surgeons SAEVA - South African Equine Veterinary Association

SIVE - Societa Italiana Veterinari per Equini

Harness Racing NZ The Donkey Sanctuary

40 Eq Vet Pract 2021, March; 46 (1)

PREPUBIC TENDON RUPTURE* Erica Gee e.k.gee@massey.ac.nz

The prepubic tendon extends from the brim of the pelvis to join with the abdominal muscles in supporting the abdomen and abdominal viscera. The prepubic tendon can partially or fully rupture with or without involvement of the associated muscles of the abdominal wall. Prepubic tendon rupture is an uncommon but serious condition usually occurring in late pregnancy that may have a poor prognosis with death of the mare and fetus.

The exact cause of prepubic tendon rupture is not known, but most often no known external injury precedes the problem.

However, the condition is more common in older, multiparous mares, mares carrying twins, often of draft breeds and in mares with placental abnormalities such as hydrops (hydroallantois or hydroamnion).

Mares with prepubic tendon ruptures exhibit signs of colic and a reluctance to move or to spend more time lying down.

Changes in the shape of the ventral abdomen may be first noted, followed by a rapidly progressive oedematous swelling that can extend from the udder towards the sternum. The udder may be swollen, and teats may point lateral and cranial instead of ventral, and blood may drip from the teats. Touching the ventral abdomen is often resented. Some mares will adopt a ‘sawhorse’ stance with a tilted pelvis and elevation of the tailhead. Other mares may die after a short illness. Diagnosis of prepubic tendon rupture is difficult to confirm and is usually based on characteristic clinical signs.

The choice of therapy for mares with prepubic tendon rupture varies dependant on the extent of the rupture, an ability to control the mare’s pain, and the stage of gestation. The relative value of the mare and foal also needs consideration.

Complete rupture of the prepubic tendon has a poor prognosis for the mare because the tendon cannot be surgically repaired.

Conservative therapy will usually involve restricting the mare to stall rest, carefully applying belly bandages or other abdominal support, and cautious use of analgesic drugs.

Progestins may be given to promote uterine quiescence. Close monitoring of the fetus to detect fetal stress is required with frequent ultrasound examinations via the mare’s abdomen to monitor fetal heart rate and activity.

Stage of gestation is an important factor when therapy options are being considered. If the mare is close to term (≥330 days of gestation), induction of labour or a caesarean section may be considered. If the mare is induced, then foaling must be assisted as there will be limited or no ability to effectively contract the abdominal muscles during active labour. If the foal is successfully delivered, it is considered at high risk of developing problems such as neonatal sepsis.

Supplemental colostrum or plasma for transfusion should be available, and the foal may not be able to suckle the mare due to severe udder swelling.

For mares that rupture the prepubic tendon before 330 days of gestation and in which pain can be managed, a decision may be made to support the mare so the fetus can reach 330 days of gestation or longer. The last part of pregnancy is very important in determining viability of the foal, as most of the fetal maturation that ensures the foal is ready for ex utero life takes place in the last 10 days of gestation. For mares in which pain cannot be well managed, euthanasia needs to be strongly considered.

Finally, mares suffering from prepubic tendon rupture that survive foaling or caesarean section should not be bred again. Notwithstanding, some mares that survive foaling may subsequently need to be euthanized due to intractable pain.

* Re-edited from Equine Disease Quarterly 2021; 30(1): 3, with permission of the author.

Eq Vet Pract 2021 March; 46 (1) 41

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THERIO CONFERENCE DECEMBER 2020 SYNOPSES OF SELECTED PAPERS Erica Gee | e.k.gee@massey.ac.nz

As with many conferences in 2020 the Therio Conference, organised by the Society for Theriogenology and the American College of Theriogenologists, was offered online as a result of the Covid-19 pandemic. Online registration allowed participants to watch the presentations ‘live’ or watch the recorded presentations online for up to 6-months after the virtual conference, to write notes that were saved and could be retrieved at a later date, and to download the conference proceedings. Posters were also available for viewing online and were accompanied by 3-minute PowerPoint presentations.

Synopses of elected abstracts relating to the postfoaling mare that may be of interest to veterinarians in New Zealand are given below. The full proceedings are available HERE.

UTERINE PROLAPSE Uterine prolapse is considered a rare event in horses, and there are relatively few reports in the literature. In a poster presentation Ghislaine Dujovne (Bove et al. 2020) presented a retrospective review of uterine prolapses and outcomes at the UC Davis Veterinary Medicine Teaching Hospital over a 30-year period. Twenty-four mares aged 4-23 years were presented for uterine prolapse, ranging in parity from 1 to 13, with 7 mares being maidens, and Arabian mares being over-represented.

Uterine prolapse occurred within one hour of foaling for 82% of mares, and 63% of mares had attached fetal membranes at the time of uterine prolapse. Only 33% of prolapses occurred after dystocia, and 17% followed abortion, with 75% of mares surviving to discharge from hospital. Five mares had acute and fatal haemorrhage associated with prolapse, and one other mare died from secondary peritonitis. No details were given of how mares with uterine prolapse were treated.

Not all uterine prolapses occur within an hour of foaling.

Veterinary student Joanna Kania et al. (2020) presented a poster on a clinical case of delayed uterine prolapse post-abortion of twin fetuses in a Thoroughbred mare seen at the VirginiaMaryland College of Veterinary Medicine. The mare had received repeated field-treatments for retained fetal membranes including initial gentle manual traction, lavages, oxytocin and flunixin injections after aborting twins overnight, and subsequently was hospitalised as the mare’s clinical signs, including increased digital pulses and injected mucus membranes, worsened. At the referral centre the mare was treated with IV fluids, uterine lavage under sedation, oxytocin, flunixin and broad-spectrum antibiotics.

Eight hours after presentation at the referral facility the mare prolapsed her uterus. The prolapse was corrected after the mare was given an epidural anaesthetic, the uterus was lavage twice daily, and the mare remained on antibiotics, IV fluids, oxytocin and flunixin. Four days later the mare was discharged, with no further complications reported. Although the time frame between foaling and prolapse of the uterus was not clear this case shows uterine prolapse can occur more than 8-hours after foaling in a mare with retained fetal membranes.

Justin McNaughten et al. (2020) of the New Bolton Center, University of Pennsylvania, reported iatrogenic prolapsing of the uterus of a post-foaling mare in order to repair a uterine tear. The mare’s dystocia had been successfully resolved by controlled vaginal delivery under general anaesthesia, with a live foal resulting. The mare was examined after recovery from general anaesthesia and transabdominal ultrasound revealed echogenic, free fluid present in the abdomen. Analysis of a sample of haemorrhagic abdominal fluid showed elevations in the nucleated cell count, lactate concentration and total protein content. Digital manual examination of the uterus identified a 10-15cm full thickness tear on the dorsal uterine body. Under general anaesthesia a midline celiotomy was performed but surgical repair of the uterine tear was not possible due to its location. While in dorsal recumbency the uterus was manually prolapsed through the vagina by pulling on the fetal membranes, allowing visualisation and repair of the tear. Fetal membranes were removed by catherization of umbilical vessels and infusion of water (referred to as the ‘Dutch method’) and the mare recovered without complications. The following season she was rebred, and subsequently gave birth to a healthy foal.

INFLAMMATORY MARKERS IN THE POST-FOALING MARE Mette Christoffersen et al. (2020) from the University of Copenhagen conducted a retrospective case control study to look at inflammatory markers in postpartum mares. Cases included 72 clinically healthy mares with sick foals, and 46 mares with periparturient complications: 9 metritis; 13 dystocia; and 24 mares with ‘other’ problems. The authors found that the blood inflammatory markers SAA and WBC were not affected by normal parturition and can be used to monitor inflammation and infection in mares with peripartum complications. Healthy postpartum mares had increased plasma fibrinogen concentrations within first 7 days after parturition, but periparturient complications resulted in higher fibrinogen concentrations compared to concentrations in normal postpartum mares. A major fibrinogen response indicates periparturient complications in a postpartum mare, and together with SAA and WBC, can be used to monitor

Eq Vet Pract 2021 March; 46 (1) 43

the inflammatory response related to obvious and occult periparturient complications.

UTERINE INVOLUTION IN THE POST-FOALING MARE Carleigh Fedorka et al. (2020) from the University of Kentucky investigated the effect of mycobacterial cell wall fraction (MCWF) on uterine involution in the post foaling mare. The inmmunomodulator MCWF has previously been shown to reduce bacterial growth and to alter aspects of the immune response of mares at breeding. Control mares (n = 4) received 1.5 ml LRS intravenously on day 1 postpartum and again 7 days later, while experimental mares (n = 6) received 1.5 ml Settle® (MCWF) IV on day 1 and again 7 days later. All mares were assessed every 3 days for clinical, immunological, and histological parameters until day 15 postpartum. Involution was considered complete by day 15 postpartum in all mares, and day postpartum had significant effect on all parameters investigated, indicating involvement of immunological process in uterine involution.

Treatment with MCWF decreased severity of bacterial growth, in addition to time to obtain clean culture. MCWF treatment increased expression of proinflammatory cytokines. The authors

concluded that while the treatment effect was small, there was histological evidence for decreased mucosal inflammation in MCWF-treated mares. Further studies are needed to determine whether an immunomodulator will improve first oestrous cycle fertility in postpartum mares.

REFERENCES Fedorka C et al. (2020). Effect of mycobacterium cell wall fraction on histological, immunological, and clinical parameters of equine uterine involution. Clin Theriogen. 12 (3): 368.

Boye J, Dujovne G (2000) Retrospective review of uterine prolapse in mares. Clin Theriogen. 12 (3): 416.

Kania J et al. (2020). Delayed uterine prolapse in a Thoroughbred mare with retained fetal membranes. Clin Theriogen. 12 (3): 437.

McNaughten J et al. (2020.) Repair of a full thickness uterine tear via iatrogenic uterine prolapse in an anesthetized Thoroughbred broodmare. Clin Theriogen. 12 (3): 400.

Christoffersen M et al. (2020.) Use of serum amyloid A and other inflammatory markers to monitor inflammatory response in mares with periparturient complications. Clin Theriogen. 12 (3): 391.

PROVIDING THE BEST OF HEALTH AND PERFORMANCE CARE

MASSEY VETS

EQUINE

A multi-speciality group of vets and researchers with a broad range of expertise and knowledge Our specialised services include: • Elective and emergency surgery including but not limited to: – Arthroscopy – Colic surgery – Airway surgery including laser surgery

• Neurology

• Investigation and treatment of: – Lameness – Poor performance – Weight loss – Respiratory disease – Colic

• Advanced imaging including: – Digital radiography – Ultrasonography – Videoendoscopy and Gastroscopy – Dynamic endoscopy – Computed Tomography (CT)

• Ophthalmology • Neonatology • Cardiology • Theriogenology

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44 Eq Vet Pract 2021, March; 46 (1)

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MASSEY EQUINE HOMEPAGE A NEW YEAR, A NEW DECADE For many the close of the breeding season, the completion of the National Yearling Sales, and the end of summer equestrian competitions provides time for a breather or a brief vacation.

Here we are welcoming our new pre-veterinary students for a new first year experience, and our 5th year students with a mixed 4th year of online and in person learning experiences due the COVID response, The financial challenges arising from the last year will be major focus of the University, with an increased commitment to online course delivery. The rebuild of the veterinary school is continuing with the new post-mortem facility due to open shortly. Preparation for international reaccreditation of the BVSc programme is well under way.

horse riding, and visiting her favourite city, Wellington. “ I am looking forward to exploring more of NZ and mixing in more overnight hikes this year.” Tia Holyoake grew up Northland (Whangarei) and came to Massey straight out of high school to complete her veterinary degree. Tia says: “My interest has always been biased towards equine medicine, with the majority of my experience stemming from playing competitive polocrosse across New Zealand and Australia. I’m a kiwi through and through, love being in the outdoors whether it be land or sea, with a particular interest in marine mammal conservation and surfing. I’m beyond enthused to kick start my veterinary career here at Massey and excited to see what the next 12 months will bring!” Our third new intern, Mikaela Nipper, hails from Auckland and completed her first year of university at Otago University before moving to Palmerston North for her veterinary degree. Mikaela remarks: “I have been fortunate enough to have a barnyard worth of pets throughout my childhood, including chickens, lambs, calves, cats, dogs, and ponies. I now only have two dogs, who love going for runs at the river and playing in the sea.” While at university for her degree she got her “horse fix” by working as a stable hand at the Awapuni race track. She is excited to get her veterinary career started with Massey this year.

The new post-mortem room.

We wish our departing interns Matthias Lim, Ingeborg ten Houte de Lange and Shaan Mocke all the best in their future endeavours.

PEOPLE

OUTREACH Emma Gordon attended the 2020 American College of Veterinary Internal Medicine, which ran online through December 2020 and January 2021.

New interns Tia Holyoake (left), Mikaela Nipper (centre), and Elsje Marneweck (right).

Dr. Roland Shubotz has extended his stay with us for six weeks. This year we welcome three new intern, all recent (2020) graduates of our BVSc programme. Elsje Marneweck is originally from South Africa but grew-up all over the United States. In her free time she likes to take her dog for long hikes, and relax reading in her hammock. Elsje also enjoys running,

Members of the Equine Veterinary Clinic and Massey University Veterinary Emergency Response Team, including Chris Riley, Emma Gordon, Mikaela Nipper and Fiona Hulse (EVC Vet Technician) recently responded to rescue a horse that had fallen upside down in a hole that was dug to place a large water tank. Quick thinking from the VERT team supported by the EVC staff ensured the safe and prompt recovery of the horse. The horse had a few scrapes and bruises but was happy to get back to grazing after an eventful morning.

Chris Riley and his MSc student Steve De Grey are presenting a paper entitled “Identifying, understanding and preventing injuries and illness for responders to technical animal rescues and disasters” at the 2021 Global Animal Disaster Management Conference, an international online conference with over 750 attendees. This presentation builds on previous work looking at the mental well being impacts of these events on responders.

Eq Vet Pract 2021 March; 46 (1) 45

Distressed horse entrenched at bottom of water tank pit.

Successful outcome due to efforts of Massey VERT team.

RECENT PUBLICATIONS Colborne GR, Liqiong Tang L, Adams BR, Gordon GI, McCabe BE, Riley CB. A novel load cell-supported research platform to measure vertical and horizontal motion of a horse’s centre of mass during trailer transport. Journal of Equine Veterinary Science 2021; https://doi.org/10.1016/j.jevs.2021.103408 Dai, F, Zappaterra M, Minero M, Bocchini F, Riley CB, Padalino B. Equine transport-related problem behaviors and injuries: A survey of Italian horse industry members. Animals 2021, 11(1), 223; https://doi.org/10.3390/ ani11010223 Kamm JL, Riley CB, Parlane N, Gee EK, McIlwraith CW. Interactions between allogeneic mesenchymal stromal cells and the recipient immune system: A comparative review with relevance to equine outcomes. Frontiers in Veterinary Science (Veterinary Regenerative Medicine) 2021: 617647; https://doi.org/10.3389/fvets.2020.617647 Riley CB, Pfeffer H, MacLachlan C, Wakeford L, Gibson IR, Benschop J, Lawrence KE. Isolates, antimicrobial susceptibility profiles and multidrug resistance of bacteria cultured from sampled collected from Sheep in New Zealand (2003-2016) NZ Vet J 2021; 69(1): 20-26

Warm Regards from the Massey Equine Team

46 Eq Vet Pract 2021, March; 46 (1)

ADVERTORIAL

EQUINE DRUG NEBULISERS The concept of nebulization of drugs in equine medicine is not new (Votion et al. 1997). Around the world, horses of all disciplines, breeds and ages are affected by respiratory issues, notably Equine Asthma and Inflammatory Airway Disease. However, the days of 24/7 turnout for asthma prone horses is not always a viable option for modern day horse keeping, particularly those competing in sports. Likewise removing horses affected by the PastureAssociated form of Equine Asthma often is impractical. Also, administration of systemic medication long term often is not a feasible option for many reasons in managing the resulting respiratory and performance issues.

Nebulisation devices enable veterinary clinics, trainers and owners to help manage a wide range of both acute and chronic respiratory issues, utilizing low doses due to targeted medication delivery, and have become the mainstay of treatment for alleviating the effects of lower airway conditions (Calzetta et al. 2017; Cha and Costa 2017).

Calzetta, L., P. Roncada, D. di Cave, L. Bonizzi, A. Urbani, E. Pistocchini, P. Rogliani, and M. G. Matera.

2017. “Pharmacological treatments in asthmaaffected horses: A pair-wise and network metaanalysis.” Equine Veterinary Journal 49 (6): 710-717. https://doi.org/10.1111/evj.12680. <Go to ISI>:// WOS:000412910300004.

Cha, M. L., and L. R. R. Costa. 2017. “Inhalation Therapy in Horses.” Veterinary Clinics of North America-Equine Practice 33 (1): 29-+. https://doi. org/10.1016/j.cveq.2016.11.007. <Go to ISI>:// WOS:000399258100004.

Votion, D., Y. Ghafir, K. Munsters, D. H. Duvivier, T. Art, and P. Lekeux. 1997. “Aerosol deposition in equine lungs following ultrasonic nebulisation versus jet aerosol delivery system.” Equine Veterinary Journal 29 (5): 388-393. https://doi.org/10.1111/j.2042-3306.1997. tb03145.x. <Go to ISI>://WOS:A1997XW64000013.

The use of completely silent, portable and comfortable nebulisation devices such as Flexineb E3™ specifically designed for the veterinary equine market now are available.

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Eq Vet Pract 2021 March; 46 (1) 47

SURVEILLANCE REPORTS BIOSECURITY NEW ZEALAND

We hope readers appreciate seeing a synopsis from the latest reports in MPI Surveillance for reported clinical laboratory equine cases.

Excerpted and edited with agreement from MPI. As for all items, we would appreciate receiving feedback on the usefulness of this feature for EVP. Biosecurity New Zealand’s Incursion Investigation team investigates suspected cases of emerging or exotic diseases in New Zealand. They are interested in hearing about any equine health issues that seem out of the ordinary, including but not limited to: • Parasites or unexplained disease in one or more horses associated with recent international travel • An unusual or unexplained outbreak in a group of horses, particularly involving: – – – –

acute respiratory disease neurological signs abortion/reproductive signs unexplained mortalities

If you suspect you’ve seen an exotic or emerging disease, please phone Biosecurity New Zealand on 0800 80 99 66 as soon as reasonably practical.

SUSPECTED EQUINE EXOTIC DISEASES Accessed and edited from Surveillance. 2020; 47 (4), Jan 27th, 2021

Theileria equi confirmed in imported mare A scientist from the AHL (Wallaceville) called the exotic pest and disease hotline to report seropositivity on both cELISA and IFAT to Theileria equi in a mare being prepared for export to Australia. The presence of the equine piroplasmosis agent T. equi was confirmed in a blood sample by molecular testing, including DNA sequencing.

The mare had been imported from the UK the previous year, and prior to this had raced in France, where T. equi is endemic. At the time of import the mare had met the requirements of New Zealand’s import health standard, which included a negative cELISA test for T. equi during the 21 days prior to importation.

On the basis of this detection, a biosecurity response was initiated. Response activities included testing all horses on the two properties where the mare had been located. In addition, all horses that had been resident on the two properties but moved off since the arrival of the infected mare, were traced and tested, all with negative results. In the interim period the infected mare was re-exported to France. Transmission of equine piroplasmosis is primarily through a competent tick vector. New Zealand’s endemic tick, Haemaphysallis longicornis, is not a vector for T. equi. The 48 Eq Vet Pract 2021, March; 46 (1)

investigation concluded that the introduction was limited to one imported mare, and on 8 October 2020, in accordance with Article 1.4.6. item 2c of the Terrestrial Animal Health Code, New Zealand considered that appropriate surveillance had been completed to demonstrate that T. equi had been eradicated, declaring the country’s status as free from T. equi (Zohrab 2020).

Babesia caballi excluded: two cases An AHL (Wallaceville) scientist notified the duty Incursion Investigator of a positive Babesia caballi cELISA test result in a horse being prepared for export to Australia. To meet Australian access requirements, horses must return negative B. caballi tests by both cELISA and IFAT. The horse was a 5-year-old Standardbred gelding that had been born in Australia and imported into New Zealand in June 2018. Babesia caballi is exotic to both New Zealand and Australia, and the weak positive cELISA test was considered to be a false positive result. Four weeks later, followup serum and EDTA blood samples were collected for repeat serological and molecular testing at the AHL (Wallaceville). The EDTA sample returned a negative PCR result, but the cELISA test again returned a weak positive. To clarify this result, blood samples were submitted to the OIE Collaborating Centre for Surveillance and Control of Animal Protozoan Diseases (Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan), where PCR, cELISA and IFAT tests all yielded negative results. Babesia caballi was excluded and the investigation was closed, with the gelding eligible for export to Australia.

In the second case, an AHL scientist reported a positive B. caballi IFAT titre (1 : 320) in a pre-export blood sample taken from a 24-month-old Standardbred colt. The result had been reported with the proviso that the staining that occurred as part of the test was not typical of a true positive. Testing had been carried out as part of routine pre-export testing and there were no clinical signs in the horse to indicate a true infection with the agent. The blood sample was provided to the OIE Collaborating Centre for Surveillance and Control of Animal Protozoan Diseases (Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan) for follow-up testing. All tests (PCR, cELISA and IFAT) were negative for both T. equi and B. caballi. Exotic disease was excluded and the investigation was closed.

Exotic causes of equine anaemia excluded: three cases A pathologist contacted MPI via the exotic pest and disease hotline to report a gelding with clinical signs of dependent oedema and anaemia, potentially consistent with equine viral arteritis.

Serum submitted to the AHL (Wallaceville) tested negative by AGID and VNT for equine infectious anaemia and equine viral arteritis virus, respectively. Similarly, samples were negative for

both agents by molecular testing. The gelding was found to have a primary immune-mediated thrombocytopenia. Exotic viral diseases were ruled out and the case was stood down.

A pathologist called the MPI exotic pest and disease hotline to report a 6-year-old Thoroughbred mare with clinical signs of dependent oedema, potentially consistent with a viral arteritis.

Serum and nasal swabs were submitted to the AHL (Wallaceville).

Testing of serum by AGID for equine infectious anaemia, and by VNT for equine viral arteritis, returned negative results. Swabs were also negative for each agent by real-time PCR. The dependent oedema resolved over the following week without incident. Exotic disease was excluded and the investigation was stood down.

A private veterinarian notified MPI via the exotic pest and disease hotline of a syndrome in horses that had occurred on a property for more than a year. About 12 of 30 horses (40 percent) that had been grazed on the property for variable periods were affected, with a case fatality rate of 50 percent (6/12). The key clinical signs were diarrhoea, colic and anaemia. The 11 horses that were present on the property at the time of investigation were blood tested for exotic agents causing anaemia. All horses were serologically negative by AGID to equine infectious anaemia (EIA) and negative for Babesia caballi and Theileria equi by competitive ELISA test. Cyathostomiasis has been associated with anaemia, hypoalbinaemia and a low albumin-to-globulin ratio (Corning 2009). Of the 11 horses tested, three were anaemic (HCT < 0.32; (reference range 0.32–0.55)), seven had low albumin ( < 27 g/L; reference range 27–39), eight had an albumin-to-globulin ratio below the minimum limit of the adequate range (0.62–1.46) and seven showed eosinophilia on a blood smear. Although none of the 11 horses from which faecal samples were collected had cyathostome larvae in the faeces, one other sample had over 600 eggs per gram. No other animal species cross-graze the property.

One of the horses died during the investigation and a post-mortem examination was conducted. Tissues collected during necropsy showed histological evidence of a colitis with an underlying chronic-active cyathostominosis and an eosinophilic enteritis, which was likely due to endoparasites. Thus, cyathostominosis, along with endoparasitism was the most likely presumptive cause of the clinical signs seen. Exotic disease was excluded and the investigation was stood down.

References Corning, S. (2009). Equine cyathostomins: a review of biology, clinical significance and therapy. Parasites & vectors, 2(2), S1.

10.1186/1756-3305-2-S2-S1.

Zohrab T (2020). Equine piroplasmosis New Zealand. OiE Final report No. 16. 8 October 2020. Accessed 09/02/2021.

EQUINE CLINICAL DIAGNOSTIC LABORATORY CASES Accessed and edited from Surveillance. 2020; 47 (4), Jan 27th, 2021

SVS Laboratories A 7-year-old gelding from Matamata-Piako presented with suspected avocado toxicity. The troponin I concentration was 671 ng/L (reference < 40), supporting the presence of myocardial injury.

The leaves, fruit, seeds and bark of avocado trees are poisonous to horses as they contain persin, a cardiac toxin. Clinical signs include facial oedema and pleural effusion, associated with decreased cardiac function. A 2-year-old gelding horse in Waikato had a growth at the base of its lower right incisors. Punch biopsies were taken. Histopathology showed spindle cells on a fibroblastic stroma that blended with zones of osteoblastic cells lining osteoid and bony trabeculae. Proliferating trabeculae had formed perpendicular to proliferating spindle cells. These changes were suspected to be an equine juvenile ossifying fibroma, a benign, progressive proliferation of fibro-osseous tissue commonly seen in the rostral mandible. It is most common in juvenile equids up to 2 years of age. The origin of this tumour is unknown, but it could be due to developmental interference with the intramembranous ossification process of the mandible, or trauma related. The lesion is often locally aggressive, but no incidents of metastasis have been reported.

IDEXX Laboratories Streptococcus equi ssp. equi was isolated from a submandibular abscess in a 2-year-old pony from Kapiti, confirming a diagnosis of equine strangles. Quarantine and biosecurity measures to control this highly contagious disease were implemented as well as disinfection of items related to indirect transmission (troughs, feed buckets, grooming kits, etc).

Gribbles Veterinary Pathology A 13-year-old male Standardbred horse on a Canterbury property developed moderate diarrhoea and swelling of the face, limbs and prepuce. It had been most recently treated with anthelmintics 6 months previously. Haematology and biochemistry testing were undertaken and relevant findings included an increased neutrophil count of 17.2 x 109 cells/L (reference range 2.7–6.7 x 109), suggesting stress or inflammation, along with a reduced serum albumin concentration of 15 g/L (reference range 27–39), consistent with a protein-losing enteropathy. Examination of a faecal sample revealed 1,200 cyathostome larvae per gram of faeces, supporting a diagnosis of cyathostomiasis.

FREE BEVA MICROSITE As NZEVA members you have free access to the new BEVA microsite. Through this site you can LISTEN, WATCH, VIEW and READ all accessible videos, infographics, podcasts, and EVJ Virtual Issues and Highlighted Papers. The site is refreshed monthly.

Your NZEVA Executive may be able to arrange for reduced rates for International Full BEVA membership – keep watching.

Eq Vet Pract 2021 March; 46 (1) 49

AMERICAN ASSOCIATION OF EQUINE PRACTITIONERS

SELECTED AND EDITED SYNOPSES FROM PROCEEDINGS OF 66TH ANNUAL VIRTUAL AAEP CONFERENCE 2020

Role of Dietary Pro-Resolving Lipid Mediators in Resolution of Equine Asthma Carla J. Olave et al.

Purdue University Omega-3 polyunsaturated fatty-acid (𝛀-3)-derived, pro-resolving lipid mediators (PRLMs) promote resolution of inflammation by increasing neutrophil apoptosis and clearance. Mild asthmatic horses previously on hay were fed pellets (low 𝛀-3, n = 10) or haylage (high 𝛀-3, n = 9) for 6 weeks. Bronchoalveolar lavage (BAL) was performed at zero, three and six weeks while dust exposure was measured. Neutrophils apoptosis and their removal by alveolar macrophages were quantified by flow cytometry.

Dust exposure was higher with hay feeding (P < 0.01) and equivalent between haylage and pellets (P = 0.9). BAL neutrophil % decreased in horses fed haylage (baseline: 11.8 ± 2.4%; week 6: 2.5 ± 1.1%; P = 0.0017) but not in those that were fed pellets (baseline: 12.1 ± 2.3%; week 6: 8.5% ± 1.7%; P = 0.28). At week 6, horses eating haylage had lower BAL neutrophil % than those on pellets (P = 0.014). PRLM treatment showed no effect (P > 0.9). Only horses fed haylage displayed reduced airway inflammation despite similar dust exposure to those fed pellets. This improvement was not associated with level of dust exposure nor was due to PRLMs influence on neutrophil apoptosis and removal. Thus feeding haylage improves airway inflammation in mildly asthmatic horses beyond that due to reduced dust exposure, although the mechanisms are still unclear.

Effects of Low-Dust Forages on Racehorse Airway Health Laurent L. Couëtil Purdue University

This study compared levels of respirable dust exposure and bronchoalveolar lavage (BAL) fluid cytology between racehorses fed dry hay, steamed hay, and haylage.Thoroughbred racehorses (n = 73) were randomly assigned to fed hay, steamed hay, or haylage diets for 6 weeks. A BAL was performed at zero, three and six weeks and respirable dust was measured in the horses’ breathing zones on two occasions, for most horses. Feeding steamed hay (0.056 ± 0.018 mg/m3) or haylage (0.053 ± 0.016 mg/m3) reduced horses’ exposure to respirable dust compared to feeding hay (0.078 ± 0.037 mg/m3; p < 0.05). Horses eating haylage had a lower proportion of BAL fluid neutrophils at week 3 (p = 0.025) and week 6 (p = 0.003) compared to baseline and to hay at week 6 (p = 0.04). Horses eating haylage exhibited a decrease in mast cell proportions only at week 3 (p = 0.008). These results suggested that feeding steamed hay and haylage reduced respirable dust exposure, while only haylage feeding significantly decreased airway inflammation.

Impact of Concurrent Treatment with Omeprazole on Phenylbutazone-Induced Gastric Ulceration in Horses Megan Ricord et al.

Louisiana State University Twenty-two horses with equine glandular gastric disease (EGGD) and equine squamous gastric disease scores ≤2 were assigned to three treatment groups receiving phenylbutazone (PBZ; 4.4 mg/kg PO q12h), or phenylbutazone plus omeprazole (PBZ/OME; 4 mg/kg PO q24h), or placebo (CON) for up to 14 days and gastroscopy was performed weekly. EGGD score increased over time, with PBZ group score increasing more than PBZ/OME group (p = 0.04). Total plasma protein decreased over time in PBZ (p = 0.003) and PBZ/OME groups (p = 0.01). Rate of intestinal complications, including large or small colon impaction, diarrhoea, necrotizing typhlocolitis, and ulcerative and necro-haemorrhagic enterocolitis was higher in PBZ/OME group (6/8) versus CON group (0/6; p = 0.02) but not PBZ/OME group versus PBZ group (2/8; p = 0.3). Thus, although administration of omeprazole ameliorated PBZ-induced EGGD, it was associated with an increase in intestinal complications, therefore caution should be exercised when co-prescribing NSAIDs and omeprazole in horses 50 Eq Vet Pract 2021, March; 46 (1)

Racing Performance of Yearlings Identified with Subchondral Cystic Lesions of the Distal MC3/MT3 Condyle Mitja Miklavcic et al.

Hagyard Equine Medical Institute Repository, pre-sale radiograph [2005-2017] reports of 42 yearlings from one farm with nonclinical subchondral cystic lesions [SCLs] of the distal MC3/MT3 and a cohort of 84 unaffected yearlings without SCLs were studied. Racing metrics were available for all horses. History of treatments pre- or post-sale was unknown. No significant differences were observed between horses with and horses without SCLs of the distal condyles both for racing metrics and monetary performance. There was a trend for larger cysts with articular involvement to limit performance. These findings may cause veterinarians to consider recommendations when advising clients on yearlings with nonclinical SCLs.

Anti-PNAG Titers Correlate with Protection Against Rhodococcal Foal Pneumonia Susanne K. Kahn Texas A&M University Following transfusion with polysaccharide poly-N-acetyl glucosamine (PNAG) hyper-immune plasma (HIP), antibody titers to PNAG and complement deposition onto PNAG correlated with protection against presumed Rhodococcus equi pneumonia. This study was conducted at two large breeding farms [n = 120 foals each] with a history of R. equi pneumonia. Foals were randomly assigned to be transfused within 24 hours of birth with 2 L (≈40 ml/kg) of either anti-PNAG or anti-R. equi HIP and monitored for evidence of R. equi pneumonia. Titres to PNAG and C1q titres were significantly (P < 0.05) higher among foals protected against either clinical or subclinical presumptive R. equi pneumonia, but VapA titres were not under these field conditions.

EDUCATIONAL VIDEOS Readers might enjoy viewing video lectures on the following topics at the two links below. These are produced for the Beaufort Cottage Educational Trust and sponsored by the Gerald Leigh Family Trust.

THOROUGHBRED SALES 1.

2.

3.

4.

5.

6.

7.

8.

Welcome and introduction - Nick Wingfield Digby Sales selection - The trainer’s view point - Sir Mark Prescott The Sales Exam - The veterinary viewpoint - Mike Shepherd Do foal injuries and diseases compromise sales and racing performance - Celia Marr Radiography at the Sales - Are findings associated with future performance Pt1 - Debbie Spike-Pierce Radiography at the Sales - Are findings associated with future performance Pt2 - Debbie Spike-Pierce Does conformation affect gait - Objective assessment - Renate Weller Genomics and performance profiling - Where are we heading - Des Leadon

9. A personal view on producing and selecting horses for racing and breeding - Luca Cumani

MUSCULOSKELETAL IMAGING OF THE EQUINE ATHLETE 1.

2.

3.

4.

5.

6.

7.

8.

9.

Radiographic findings in Juvenile Orthopaedic Disease - Debbie Spike Pierce Soft tissue injuries of the foot are there red flags on plain radiography - Marianna Biggi Has advanced imaging changed the management of proximal suspensory desmitis - Sue Dyson Imaging & clinical management of suspensory branch injury in racing thoroughbreds - Pete Ramzan Third phalangeal cysts in the Thoroughbred Racehorse - Tom O’Keeffe Imaging the equine back - Marianna Castro Martins Fractured ribs - Diagnosis and prognosis - Billy Fehin Pelvic ultrasonography - Sarah Boys Smith Sub clinical imaging findings in the elite sport horse - How do we determine relevance - Sue Dyson

Eq Vet Pract 2021 March; 46 (1) 51

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Nuclear Scintigraphy with motion correction Digital radiography and ultrasonography Overground video endoscopy New to the South Island Power and Manual Dentistry Video Gastroscopy Laser Surgery for

Respiratory and Skin Conditions, Laparoscopic Surgery.

Major sponsors of Spirit Eclipse and the Ronald McDonald House SI Polo Fund Raising 2016.

Also sponsoring both Racing Codes, NZ Equestrian Sports, Riding Clubs & Junior Drivers of Harness Racing.

499 Springs Road, Prebbleton, Christchurch

Phone : 03 349 4791

Email : staff@canterburyequine.co.nz

52 Eq Vet Pract 2021, March; 46 (1)

FREE WEBINAR RECORDING IMMUNOMODULATION IN MARES On-line presentation from University of Kentucky Gluck Equine Research Center Edward Squires Moderator Mats H.T. Troedsson Use of Immune modulators in the treatment of equine endometritis Carleigh Fedorka Immunomodulation in the postpartum mare An up-to-date discussion on the use of immunomodulators in clinical practice available HERE

PROCEEDINGS 2020 ACVIM FORUM-ON-DEMAND

SELECTED EDITED ABSTRACTS

The Development of a Therapeutic Antibody for Equine Endocrinopathic Laminitis Samira Rahnama et al.

Queensland University of Technology, and others.

It was proposed that high insulin levels may overstimulate IGF-1 receptors (IGF-1R) and damage the hoof lamellae. A recombinant human anti-IGF-1R monoclonal antibody [mAb] was re-engineered to avoid an immune response in the horse and expressed in Chinese hamster ovary [CHO] cells. In vitro, the resulting mAb was highly selective for binding to equine IGF-1R over insulin receptors (>60-fold), however, the mAb blocked the stimulatory effects of both peptides on cell proliferation in lamellar explants (100%, p<0.001). In vivo, when n=6 Australian Standardbred horses were subjected to a prolonged hyperinsulinaemic-euglycaemic clamp over 48 h, pre-treatment with a low dose of the mAb reduced the radiographic sinking of the distal phalanx (47%, p<0.05), and markedly lessened the histologic stretching of secondary epidermal lamellae (p<0.05). The results showed that an anti-IGF-1R mAb may aid in lessening insulin-induced laminitis.

Inflammatory Bowel Disease [IBD] in Horses Gayle D. Hallowell University of Nottingham, UK It is reasonable to consider that IBD in horses has a similar pathophysiology to the disease in other species. Currently, equine clinicians are trying to simplify treatment and assume that this is a short-term condition that will be resolved with glucocorticosteroids. If IBD shares characteristics across species, then we need to look at the inciting factors and work on dietary management to identify protein sources that incite the clinical signs. This involves considering changing the fibre source, reducing the varied carbohydrate content to one or two sources, adding in corn oil (which may have anti-inflammatory properties) and supplementing vitamin D. This can be challenging as horses are reluctant to eat simple carbohydrates. In addition, consideration of surgery if medical management is unsuccessful (especially if there may be a focal lesion that could be resected), particularly if the next option is euthanasia. In addition, we need to manage client expectations so that they understand that this is likely to be a chronic condition and may need further treatment for relapses. We also need to consider the impact of early therapy and diet in foals when we look at the risk factors in other species. These would include use of anthelmintics and antibiotics, exposure to gastrointestinal infections and rearing in very clean conditions. Ultimately what we lack are large, multi-centre studies with definitive diagnoses, thorough case histories and ultimately an understanding of the natural history of this condition in the horse.

Respiratory Gene Technology® as a Potential Treatment for Equine Asthma Sanni Hansen et al.

University of Copenhagen, Denmark Respiratory gene technology® (RGT) is a form of autologous conditioned serum (ACS) containing several fold higher levels of the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) compared with untreated serum. A control group (n=11) of TB horses with normal BAL values, and two treatment groups being an RGT-ACS treatment group (n=12) and a serum treatment group (n=13) consisting of horses diagnosed with mild equine asthma. An endoscopy including BAL was performed before (T0), after a six-week treatment period of 12 IM of RGT-ACS or serum (T6), and 10 weeks after last treatment (T16). For the control group, no difference in BAL cytology between any of the time points was found. A significant decrease in BAL neutrophils (RGTACS p<0.01; serum p<0.01) and BAL mast cells (RGT-ACS p=0.02; serum p<0.01) was found for both the RGT-ACS and the serum treatment groups between T0 and T6. A significant decrease between T0 and T16 was found for BAL neutrophils in the serum treatment group (p=0.05) and for BAL mast cells in both the serum and the RGT-ACS treatment groups (RGT p<0.01; serum p=0.03).

No difference was found between T0 and T16 for BAL neutrophils in the RGT-ACS group (p=0.49). Thus, both treatments were effective in reducing BAL neutrophils and mast cells in horses with mild equine asthma.

Eq Vet Pract 2021 March; 46 (1) 53

Clinical Response in Horses with Severe Equine Pasture Asthma to Allergen Specific Immunotherapy Ann Chapman Louisiana State University Seven horses with severe equine pasture asthma (EPA) - presence of tachypnea, nostril flaring, abdominal lift, spontaneous or inducible cough, nasal discharge, abnormal tracheal sounds, and abnormal pulmonary auscultation during summer months underwent serum and intradermal allergy testing at the onset of expected winter-time clinical remission and were kept at pasture.

Horses within the treatment group [n=4] received SC injections of dilutions of selected allergens using a standard protocol.

Standing thoracic radiographs and BAL cytology were performed on all horses prior to starting therapy, and then at days ~90, ~180, ~270 and ~365. Horses were evaluated at pre-determined intervals and short-term rescue therapy was used as indicated.

Total clinical scores improved significantly in both groups (P < 0.05) during the remission period (Day 28) and worsened during the following seasonal exacerbation period (Day 85 – 270). A time effect was noted in mean BAL neutrophilia (43.3% ± 30.6) in all horses (P < 0.05). There was no significant difference in total clinical scores and BAL neutrophilia between treatment groups.

Thus, in this situation, allergen specific immunotherapy alone did not improve clinical score or BAL inflammation in horses with equine pasture asthma.

Bile Acids, GGT, and Direct Bilirubin as Prognostic Indicators for Horses with Liver Disease Barbara Delvescovo Cornell University, New York

Recent published data from Europe supports the use of bile acids [BA] as prognostic indicator of short and long-term outcome in horses. Etiopathology of hepatic diseases in horses from USA might differ from horses included in the European study causing predictive outcome value of BA to differ.

Records of 82 horses with liver disease one or more years of age admitted to four referral centers between 1997 and 2018 with a BA measurement > 30 μmol/L and at least six months follow up information were included. The highest single BA, GGT and direct bilirubin [DB] value recorded for each horse was used for statistical analysis. 55% of the horses survived at least 6 months post-discharge. BA values were not significantly different between survivors and non-survivors (p=0.45). BA and GGT or DB were not correlated. GGT values were also not correlated with outcome (p=0.15), instead DB bilirubin values were negatively correlated with outcome (p=0.0). According to these results, BA values do not represent a reliable long-term prognostic for this population of horses with liver dysfunction from Eastern USA. Instead DB values may be more reliable indicator of prognosis in a similar population of horses.

NOTE: The situation in NZ regarding types of liver disease – viral, toxic, vascular etc. – is unclear. We understand starvation is associated with elevated serum bilirubin, especially indirect or unconjugated bilirubin in [some] horses.

Many moons ago, Kaneko and Cornelius in Clinical Biochemistry of Domestic Animals promoted the use of the ratio of direct to indirect bilirubin as a strong indicator of liver dysfunction with a ratio of > ~15% indicating degrees of liver failure. This could be used in anorectic horses with very high indirect bilirubin levels due to lack of food intake. Perhaps again we should extend our ‘liver panel’ to include not only GGT and BA but direct acting and indirect acting bilirubin levels. ED.

Blood Vitamin C, Vitamin B and Cortisol Concentrations in Healthy and Critically Ill Foals Katarzyna Dembek North Carolina State University Blood samples were collected at admission to clinic and 72 and 120 hours after admission from healthy (n = 15), septic (positive blood culture and/or sepsis score > 12 [n = 17]) and sick non-septic (SNS; n = 15 ) foals less than one week of age. The prevalence of hypovitaminosis C on admission (vitamin C <7 ug/dL) was 58 % and 26 %, in septic and in SNS foals, respectively. Hypovitaminosis B (vitamin B <2 ng/mL) was more frequent in septic foals (47%) compared to SNS (13%: (p <0.05) foals. In septic foals, vitamin B and C concentrations were lower than in healthy foals at 72 and 120 hours after admission (p <0.05). Cortisol concentration was higher in septic and SNS foals compared to healthy foals on admission (p <0.05). Low vitamin C and B concentrations were associated with severity of disease in neonatal foals suggesting that hypovitaminosis C and B may contribute to a pro-inflammatory state in equine neonatal sepsis.

54 Eq Vet Pract 2021, March; 46 (1)

US THOROUGHBRED RACING ECONOMIC INDICATORS: 2020 VERSES 2019 SARS-CoV-2 caused US TB racing prize money and number of race days to slump in 2020, but Average Wagering Per Race Day was strong.

YTD 2020 vs. YTD 2019 Indicator

2020

Worldwide wagering on US Races*

2019

% Change

$10,925,226,444

$11,033,824,363

-0.98

$869,774,080

$1,167,920,667

-25.53

3,302

4,425

-25.38

U.S. Races

27,700

36,207

-23.50

U.S. Starts

220,006

272,553

-19.28

7.94

7.53

+5.51

$3,308,669

$2,493,520

+32.69

$263,408

$263,937

-0.20

U.S. Purses U.S. Race Days

Average Field Size Average Wagering Per Race Day Average Purses Per Race Day

FULL PROCEEDINGS AVAILABLE ONLINE British Equine Veterinary Association – Annual Congress – Birmingham, Sept 11, 2019

Register through IVIS at https://www.ivis.org/ Or go direct to proceedings HERE

VETLOGIC PUZZLE - ANSWER

See page 34 for puzzle

ANGLER

FISH

LENGTH

EMMA GORDON

BLUEFIN TUNA

2

TRISH PEARCE

MARLIN

4

LUCY RUSSELL

SWORDFISH

3

RABECCA MCKENZIE

KINGFISH

1

Eq Vet Pract 2021 March; 46 (1) 55

ANSWER

WHAT IS REQUIRED TO SET UP FOR A DISTAL LIMB INTRAVENOUS REGIONAL LIMB PERFUSION?

RECOMMENDED MINIMAL MATERIALS REQUIRED 1. Appropriate IV sedation: e.g. detomidine (0.01mg/kg) and butorphanol (0.01mg/kg) 2. Mepivacaine to perform a perineural nerve block if required 3. Medication to be infused (antibiotic, radiographic contrast, morphine, tiludronate, stem cells) 4. Scrub material 5. Butterfly catheter (23 or 25 gauge) 6. Vetwrap™ 7. Dry gauze 8. Esmarch tourniquet

PROCEDURE 1. Sedate and do low 4-point nerve block. Apply the tourniquet circumferentially to the limb proximal to the level of the injury. Gauze rolls can be placed medially and laterally to the flexor tendons in both front and hind limbs to aid in more uniform compression of the limb by the tourniquet.

2. Aseptically prepare the skin over the distended vein intended for use. Advance a butterfly catheter into the vessel and once blood is coming back, infuse the medication over 1-2 minutes. Remove the catheter and immediately place a small pressure wrap with dry 4x4’s and Vetwrap™ over the vein used to reduce haematoma formation. Leave the tourniquet in place for 20 to 30min. Removed the tourniquet prior to removing the bandage over the vein.

Place a distal limb bandage following IVRLP to reduce thrombosis or haematoma formation.

KEY TIPS 1. Limit movement as much as possible. Increased movement results in increased tourniquet escape.

2. Minimize perfusate volume (eg: 1 gram ceftiofur reconstituted to 10ml with sterile water) to decrease opportunities for extravasation and endothelial irritation. This decreases the risk for post-perfusion phlebitis. While minimal perfusate forgoes use of hydrostatic pressure, concentration gradients are maximized and clinically effective levels of medications are commonly achieved within the extravascular spaces.

Barbara Hunter | Barbara@matavet.co.nz

56 Eq Vet Pract 2021, March; 46 (1)

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SUCCESSFUL OUTCOME OF THEILERA EQUI RESPONSE New Zealand Equine Health Association World Organisation for Animal Health A declaration of New Zealand’s freedom from the equine blood disease Theilera equi was recently posted on the World Organisation for Animal Health’s (OIE) website.

In April 2020, a four-year-old thoroughbred mare destined for stud in Australia tested positive for T. equi in routine pre-departure testing. Gene sequencing testing then confirmed the horse was infected with T. equi, although she was clinically healthy. The mare had been imported from France in February 2019 for breeding purposes. Investigations concluded that she had been infected before import to New Zealand. Because the mare had been resident in New Zealand outside of quarantine, our country lost its disease free status for T. equi, causing significant concern to the equine community who faced the possibility of a new endemic disease that could severely impact the health of the New Zealand horse population. In addition, there were extra immediate costs to horse exporters who now had to comply with the additional testing requirements associated with exporting from an infected country.

A response team of representatives from MPI and the equine industry, represented by members of the Equine Health Association (NZEHA), was set up. The best scientific and veterinary resources were assembled to assess the transmission risk and design a testing regimen to determine the extent of any spread of the disease in New Zealand. After extensive research and testing no evidence was found that the disease had spread - via ticks or other mechanisms - beyond the single imported horse.

The joint effort by MPI and NZEHA has resulted in most export markets remaining accessible to New Zealand horse exports, and NZEHA spokesperson Trish Pearce says it’s hoped that the OIE declaration of freedom will see the quick removal of the extra testing requirements that most countries added last year, thus relieving the equine exporters of the extra costs and inconvenience they have faced over the past nine months. The full declaration can be read HERE.

Eq Vet Pract 2021 March; 46 (1) 57

St George LB et al. Kinematic and kinetic analyses of the gait of horses wearing novel legwear for variably limiting extension of the metacarpophalangeal joint. Am J Vet Res. 2021; 82 (1): 48-54.

Six horses were subjected to four groups: control (no legwear); inactive legwear (unlimited legwear extension); active legwear with 30o extension limitation; a ctive legwear with 20o extension limitation. Reductions in MCP joint angle were noted between the control treatment and legwear with 20o extension limitation for trot and canter (leading and trailing FL), and between inactive legwear and legwear with 20o extension limitation for trot and leading FL during canter. Interactions among peak MCP joint angular velocity, peak vertical ground reaction force, and average loading rate were not significant. The legwear may be beneficial for horses rehabilitating from flexor apparatus injuries.

Alonso JD et al. Plasma and Peritoneal Ceftriaxone Concentrations After Intraperitoneal Administration in Horses With Septic Peritonitis. J Eq Vet Sci. 2021; 96: #103310. DOI: 10.1016/j. jevs.2020.103310 Twenty-six horses with good evidence of septic peritonitis received daily intraperitoneal ceftriaxone (25 mg/kg) with or without other antibiotics, along with support therapies. Mean plasma concentrations 12 and 24 hours after administration were 1.84 ± 0.43, and 0.37 ± 0.07 µg/mL, respectively, and mean peritoneal concentrations were 5.7 ± 2.84 and 0.42 ± 0.13 µg/mL, respectively. These concentrations were lower than those reported in healthy horses and were under the minimal inhibitory concentration for enterobacteria (≤ 1 µg/mL) and for gram-positive isolates (≤ 0.5 µg/mL) at 24 hours. The results were interpreted to recommend the use of an interval of dose of 12 hours.

Talbot AM et al. Computed tomography-identified mineralisation of the longitudinal odontoid ligament of the horse is associated with age and sex but not with the clinical sign of head shaking. Vet Radiol Ultrasound. Early access. 2021: DOI: 10.1111/vru.12947 Computed tomographic images of 96 horses undergoing CT examination of the head and cranial cervical spine for various reasons were assessed for the presence of mineralisation within the longitudinal odontoid ligament.

Multivariable analysis confirmed significant associations of increasing severity of mineralisation with increasing age (p = 0.002) and being female (p = 0.038). There was no association of mineralisation idiopathic head shaking or other clinical signs investigated. The clinical significance of mineralisation of the longitudinal odontoid ligament detected on CT should be interpreted cautiously.

Kearney CM et al. Treatment effects of intra-articular triamcinolone acetonide in an equine model of recurrent joint inflammation. Eq Vet J. Early access 2020. DOI: 10.1111/evj.13396 For three consecutive cycles 2 weeks apart, inflammation was induced in both middle carpal joints of eight horses by injecting 0.25 ng LPS. After the first LPS injection only, treatment with 12 mg triamcinolone acetonide (TA) followed in one randomly assigned joint, while the contralateral joint was treated with sterile saline (control).

The TA treated joints showed significantly higher peak synovial GAG concentrations (P < 0.000) and PGE2 levels (P < 0.007) after the first inflammation induction. Significantly lower total protein levels (P < 0.04) were seen with TA treatment after the second induction and significantly lower WBCC levels were noted with TA treatment after the first (P < 0.04) and after the second (P < 0.002) inductions of inflammation. Lower general MMP activity was also seen with TA treatment after the second inflammation inductions (P < 0.01). Thus, intra-articular TA seems to have some anti-inflammatory activity up to two weeks post treatment but not at four weeks that appears to outlast a shorter-lived, potentially detrimental effect of increased synovial GAG and PGE2 levels after the first induction of inflammation.

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Alves ND et al. Addition of caffeine to equine thawed sperm increases motility and decreases nitrite concentration. Andrologia. Early access 2020: # e13918. DOI: 10.1111/and.13918 Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozenthawed semen. Qualitative semen parameters were evaluated. Sperm fertility was evaluated by artificial insemination (AI) of 16 mares with thawed ejaculates - control and 5 mM caffeine-treated groups. The addition of 5 mM caffeine induced an increase in sperm motility (38.9 ± 2.8 versus 32.6 ± 3.4%), and a decrease in nitrite concentration (11.4 ± 2.1 versus 12.8 ± 2.9 µM/µg protein, p < .05). The pregnancy rate from AI in the caffeine group was significantly higher (62.5%) than that in the control group (12.5%). These results suggest that caffeine reduced the nitrite concentration and enhanced sperm motility in thawed equine sperm, thus increasing the fertility rate in mares inseminated with caffeine-treated equine semen.

Rowland AL et al. Cross-matching of allogeneic mesenchymal stromal cells eliminates recipient immune targeting. Stem Cell Translat Med. Early access 2020; DOI: 10.1002/sctm.20-0435 In their equine model the authors demonstrated innate and adaptive immune responses after repeated intra-articular injection with major histocompatibility complex (MHC)-mismatched allogeneic mesenchymal stromal cells [MSCs], but not with MHC-matched allogeneic or autologous MSCs. Increased peri-articular edema and synovial effusion, increased synovial cytokine and chemokine concentrations, and development of donor-specific antibodies were found in mismatched recipients compared with recipients receiving matched allogeneic or autologous MSCs. In matched allogeneic and autologous recipients, but not mismatched allogeneic recipients, there was increased stromal-derived factor-1 along with increased MSC concentrations in synovial fluid. It was concluded that until immune recognition of MSCs can be avoided, repeated clinical use of MSCs should be limited to autologous or cross-matched allogeneic MSCs. When non-cross-matched allogeneic MSCs are used in single MSC dose applications, presensitisation against donor MHC should be assessed.

Horn R et al. Clinical implications of using adrenocorticotropic hormone diagnostic cut-offs or reference intervals to diagnose pituitary pars intermedia dysfunction in mature horses. J Vet Int Med. Early access 2020; DOI: 10.1111/jvim.16017 A prospective case-controlled study was made for 72 control cases and 34 PPID cases. Baseline ACTH concentrations varied by month (P < .001) with significant ‘month x age’ (P = .003), ‘month x gender’ (P = .003), and ‘month x BCS’ (P = .007) effects. Baseline ACTH concentrations were accurate to diagnose PPID (0.91 ± 0.06) with diagnostic cut-off values increasing the test sensitivity (0.61 ± 0.21 to 0.87 ± 0.05, P = .002) and reference intervals increasing test specificity (0.85 ± 0.12 to 0.98 ± 0.01, P = .01). Thyrotropin-releasing hormone stimulation improved test accuracy (0.91 ± 0.06 to 0.97 ± 0.03, P = .004). It appears that ACTH concentrations follow a circannual rhythm and vary with physiological factors. Use of specific diagnostic cut-off values increases the ability to detect mild cases and using reference intervals decreases the risk of unnecessary treatments, therefore ACTH concentrations should be interpreted within the specific clinical context.

Roach JM et al. Incidence and causes of pregnancy loss after Day 70 of gestation in Thoroughbreds.

Eq Vet J. Early access 2020: DOI: 10.1111/evj.13386 Outcomes of 3,586, Day-70 pregnancies, from 1,802 mares, were collected from eight UK TB farms, over the 20132017 breeding seasons. The incidence risk of a pregnancy failing to produce a live foal at 24 hours post-partum was 7.3% (95% CI = 6.5-8.2) equating to 7.3 cases per 100, Day-70 pregnancies. The incidences of pregnancy loss between Days 70-300 of gestation, between Days 301-315, and that of % stillbirth/perinatal death were 4.0% (95% CI = 3.44.7), 0.3% (95% CI = 0.2-0.6) and 1.4% (95% CI = 1.1-1.9) respectively. Where tissues were available, 61.1% were submitted for post-mortem examination. This gave an incidence risk of loss due to umbilical cord-related pathologies of 1.5% (95% C =I 1.1-1.9), a risk of 0.4% (95% CI = 0.2-0.6) for non-infectious placental disease, and a risk of 0.3% (95% CI = 0.2-0.6) for both infectious placentitis and EHV infection. No primary diagnosis was made in 11.2% of the cases which underwent full PM examination. It was not possible to differentiate between intra-partum stillbirth and early post-partum death.

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Fletcher JR et al. Oxytetracycline associated acute kidney injury in a neonatal foal. Eq Vet Edu. Early access 2020; DOI: 10.1111/eve.13372 A 3-day-old Australian Stock Horse filly presented with fulminant acute kidney injury after receiving 4 g IV oxytetracycline at one and at two days of age for management of flexural deformities. After an initial improvement, worsening azotaemia prompted euthanasia after 55 h of care. Necropsy confirmed proximal tubular necrosis.

Nephropathy in association with oxytetracycline administration has been rarely reported but this case highlights the need for thorough case evaluation prior to use of high dose oxytetracycline therapy for correction of flexural deformities in foals.

Easton-Jones CA et al. Immune-mediated haemolytic anaemia and thrombocytopenia in 25 adult equids: 1997-2016. Eq Vet J. Early access 2020; DOI: 10.1111/evj.13384 Twenty-five equids were diagnosed by Coombs test or flow cytometry with immune-mediated haemolytic anaemia (IMHA), immune-mediated thrombocytopenia (IMTP) or IMHA with thrombocytopenia. Controls were contemporary cases without immune-associated disease. Incidence of neoplasia was significantly higher in the study population (28%) versus controls (8%) (P = .04). Equids with primary disease were more likely to survive to discharge than equids with secondary disease (8/9 vs 7/16; P = .03; OR = 13.3; 95% CI = 1.3-134.7). Survivors had a significantly lower BUN than those that died or were euthanased (survivors, 6.1 ± 2.5 mmol/L vs nonsurvivors, 9.9 ± 3.1 mmol/L P = .003). The odds of short-term mortality were higher in horses presenting with increased BUN (OR = 19.5; 95% CI, 1.8-214.1; P = .009). Primary IMHA/IMTP cases have a reasonable prognosis whereas those with secondary disease have a poor prognosis and are frequently associated with cancer. BUN may be a useful prognostic indicator for IMHA/IMTP cases.

Tatum RC et al. Efficacy of pergolide for the management of equine pituitary pars intermedia dysfunction: A systematic review. Vet J. 2020; 266: #105562. DOI: 10.1016/j.tvjl.2020.105562 Systematic searches of electronic databases were undertaken over the period April 2019 through July 2020, identifying 612 publications, of which 28 publications met criteria for inclusion in the review. Despite marked variation in study populations, case selection, diagnostic protocols, pergolide dose, follow-up period and outcome measures, in most of the included studies, pergolide was reported to provide overall clinical improvement in >75% of cases, but reported improvements in individual clinical signs varied widely. A reduction in plasma ACTH concentrations was reported in 44-74% of cases, while normalisation of plasma [ACTH] occurred in 28-74% of cases.

Denham J, Hulme AA. Systematic Review and Meta-analysis on Sodium Bicarbonate Administration and Equine Running Performance: Is it Time to Stop Horsing Around With Baking Soda? J Eq Vet Sci. 2020; 95: #103281. DOI: 10.1016/j.jevs.2020.103281 Sodium bicarbonate administration in the hours prior to exercise is a banned practice in most racing industries but has been used as a performance-enhancing substance in horses since the late 1980s. Seven randomized controlled trials, including eight experimental exercise trials involving 74 horses, met the inclusion criteria for study. Results indicated that sodium bicarbonate administration at 2.5-5 hours prior to a standardized treadmill exercise test time-to-exhaustion for 32 horses [effect = -0.13; 95%CI = -0.64 to +0.37] or simulated race time-trial for 42 horses [effect = + 0.01; CI = -0.42 to +0.44] (both P > 0.05). The studies demonstrated minimal heterogeneity and low risks of bias. These findings reflect high-quality evidence suggesting that NaHCO3 is not performance enhancing in trained Standardbred or Thoroughbred horses.

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Bescoby SR et al. Quantitative and qualitative analysis of operator inhaled aerosols during routine motorised equine dental treatment. Eq Vet J. Early access 2020; DOI: 10.1111/evj.13379 Fifteen-minute routine, motorised odontoplasties were undertaken on cadaver heads with quantifiable air monitoring equipment placed 30 cm from the oral cavity to simulate the position of the operator’s face. Water-cooled and non-water-cooled equipment and two face masks (standard surgical and FFP3) were compared. Qualitative analysis of captured respirable air particulates was performed using scanning EM and x-ray spectroscopy. Motorised odontoplasty created particles that could reach all levels of the lung. These were composed mostly of Ca and PO4 with traces of other metals. The concentration of these respirable particulates exceeded the recommended exposure limits set by the Health and Safety Executive. The use of an FFP-3 face mask reduces the inhalation of these irritant particulates.

Ferrer GR et al. Gastric squamous cell carcinoma in the horse: Seven cases (2009-2019). Eq Vet Edu. Early access 2020; DOI: 10.1111/eve.13411 Main clinical signs included weight loss, anorexia, fever, tachycardia and tachypnoea. Some further, more suggestive clinical signs such as recurrent choke, halitosis and hypersalivation were observed. Chronic anaemia and hypoalbuminaemia were common laboratory findings. Gastroscopy identified a gastric mass in four cases (57.1%) but visualisation of the stomach was precluded in the other three horses due to distal oesophageal neoplastic infiltration and compression. Gastric wall thickening was noted with abdominal ultrasonography in four horses (57.1%). Neoplastic cells could only be detected in the peritoneal fluid of 2/7 horses. Endoscopic-guided or transabdominal ultrasound-guided biopsies allowed an ante-mortem diagnosis in three horses (42.8%). Gastric masses were identified at post-mortem examination and metastasis confirmed in the liver and/or the spleen for all four cases at necropsy. Unsuccessful palliative therapy was attempted in some cases.

Delarocque J et al. Metabolic profile distinguishes laminitis-susceptible and -resistant ponies before and after feeding a high sugar diet. BMC Vet Res. 2021; 17: #56.

The present study characterised the metabolome of ponies with varying degrees of Insulin dysregulation [ID] using basal and postprandial plasma samples in ponies fed a high-sugar diet. Samples were obtained from 10 pre-laminitic that developed laminitis and 10 non-laminitic ponies that did not develop laminitis). Significant changes in the concentration of six glycerophospholipids (adj. P ≤ 0.024) and a global enrichment of the glucose-alanine cycle (adj. P = 0.048) were found to characterise the response of Pre-laminitic ponies to the high-sugar diet. In contrast, the metabolites showed no significant association with the presence or absence of pituitary pars intermedia dysfunction in all ponies. This suggested to the authors that ID and laminitis-risk are associated with alterations in the glycerophospholipid and glucose metabolism but the prognostic value of the identified biomarkers for laminitis remains to be investigated in horses and ponies.

Akter R et al. Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses.

Aust Vet J. 2020; 98 (11): 570-573. https://doi.org/10.1111/avj.13010 Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses from mares in the same paddock and one weak foal that died soon after birth on another stud, both in Victoria, Australia, in 2019. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The diagnosis was based on detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors more commonly associated with abortion or neonatal death. C. psittaci has also been detected in association with equine abortion in New South Wales. C. psittaci poses a zoonotic risk.

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POETRY AND SONG FEATURE CATCH THE WIND Donovan

CBS Television – https://tinyurl.com/3qjzlbss

Donovan Leitch is a Scottish singer, songwriter and guitarist whose music resonates especially with all old timers – like our EVP Editor! - who grew up with his music in the 60’s.

His lyrics and style of singing are similar to Dylan’s but his great voice combined with almost simplistic guitar playing yields an inimitable sound. He uses a fingerpicking style that highlights the bass notes in the background and then overlays lovely melodies over the top.

His music is uncomplicated, uncluttered and beautiful in its simplicity.

Like Dylan he has the ability to condense his thoughts into a few words that when combined with your own imagination captures the essence of his feelings and takes you along for the ride as well. The lyrics are beautiful and once listened to just stay with you.

Like many great love songs the story of Catch The Wind is one of unrequited love …..“ when rain has hung the leaves with tears ….”

Hard to stop typing all the lyrics now I’ve started so take time out yourselves and settle back somewhere quiet so you can fully appreciate the sound and poetry.

Think we may be a bit indulgent with the accompaniment. Warm French stick, Ille de France Petit brie gently washed down with 2016 Pegasus Bay Maestro. This is a beautiful Bordeaux like blend of Merlot, Cab Sav, Malbec set for a long life. Another of the joys of living in the unhurried Mainland .

Catch The Wind Donovan

In the chilly hours and minutes Of uncertainty, I want to be In the warm hold of your loving mind To feel you all around me And to take your hand, along the sand Ah, but I may as well try and catch the wind When sundown pales the sky I want to hide a while, behind your smile And everywhere I’d look, your eyes I’d find For me to love you now Would be the sweetest thing That would make me sing Ah, but I may as well, try and catch the wind When rain has hung the leaves with tears I want you near, to kill my fears To help me to leave all my blues behind For standin’ in your heart Is where I want to be, and I long to be Ah, but I may as well, try and catch the wind Ah, but I may as well, try and catch the wind Songwriters: Donovan Leitch

BB

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Summer 2020

Corporate LATEST ISSUE OF EQUIMANAGEMENT NOW AVAILABLE: Ownership WINTER 2020 EQUIMANAGEMENT PREGNANCY of Equine IN PRACTICE: Practice STAY SAFE! HIGHLIGHTS

• Veterinary School Update • Feeding Metabolic and ‘Easy Keeper’ Horses • Research Spotlight: Honey for COVID-19 CRISIS Wounds Veterinarian-Client PRE-PURCHASE EXAMS

• Process • Communication

Tips • Communication Understand Gastric Issues

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Peripartum Mare & Foal

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Equine Muscle Disorders

Stephanie Valberg

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Acute vs. Chronic Pain Management

Earl Gaughan

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Equine Microbiome

Marcio Costa

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Equine Influenza

Wendy Vaala

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Thermochips for Horses

Alan Dorton

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Wound Management

Earl Gaughan

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Equine Colic from a Veterinarian's Perspective

Louise Southwood

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Parasite Control in Young Horses

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Controlling Estrus in Performance Mares

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Equine Coronavirus

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ALSO LISTEN TO THE DAILY VET LIFE PODCASTS Daily Vet Life is a short podcast for equine and mixed animal veterinarians and their staffs that is focused on personal and business topics of importance during the COVID-19 pandemic.

It is produced Monday through Friday.

Eq Vet Pract 2021 March; 46 (1) 63

Veterinary research and education funding available The Don McLaren Fellowship Fund Through the generosity of the McLaren family and in memory of Don McLaren and the huge contribution he made to our profession through his drug company, Bomac, a fund is available to further veterinary research and education. A significant proportion of this money is allocated to the equine sector. A total of $10,000 is available for equine research and education each year, and applications are now invited for 2020.

Priority will be given to veterinary practice-based projects, especially involving young veterinarians.

Consideration will also be given to broader-based equine research work or suitable education-related applications.

Applications close 31 October 2020 and the successful applicant(s) will be notified by 1 December.

Please apply in writing to: Leanne Fecser New Zealand Veterinary Association, PO Box 11212, Wellington nzva@vets.org.nz Applications must include: (a) Details of the proposal (b) Curriculum vitae

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