The Equine Veterinary Practitioner - March 202

The

Equine Veterinary Practitioner

The Official Publication of the New Zealand Equine Veterinary Association

MARCH 2022 Vol. 47 No. 1

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CONTENTS

MARCH 2022 PAGE NO.

President Report

3

Editorial Blog

4

Arrhythmias Katharyn Mitchell

7

Paraphimosis in a Malnourished Stallion Margaret Leyland & Erin Simpson

11

Bovine Amnion Hastens Wound Healing?

Julie Bell

17

Cervical Oesophageal Rupture in a Pregnant Mare Shaan Mocke, Gareth Fitch & JoAnna Faircloth

21

Support From Your NZEVA Executive

25

Theriogenology Clinical Poser Babiche Heil

27, 67

Drug Poser: Depot-Penicillin Stephanie Brooks

27, 66

VetLogic Puzzle

29, 66

Guttural Pouch Mycosis: An Incidental Finding?

Gareth Fitch

31

Useful Links

37

Recent VPIS Insurance Cases Paul Frazer

38

EVP Interview with Colleague Chris Riley

41

NZERF Videos

44

CPD Listing

45

Guttural Pouch Tympany Lucy Russell & Emma Gordon

47

Obituary: Peter D Rossdale

51

Massey Equine Homepage

54

EVE Podcasts

57

MPI Surveillance Reports

58

NZERF Scholarships & Grants

62

Mining For Music: Dancing the Night Away

69

Our Special Advertisers

70

Eq Vet Pract March 2022; 47(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 NZEVA Edu Comm)

Gareth Fitch

Emma Gordon

Angela Hawker

Barbara Hunter

Rabecca McKenzie

Luca Panizzi

Trish Pearce

Lucy Holdaway (NZEVA Executive Rep.)

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) , as purely an educational resource for NZVA members and their practices.. 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: The photo was taken on a beautiful day in early Autumn 2020 (actually April Fool’s Day!). It is on our lease farm in Waipahi which is just the Otago side of the Southland/Otago border.

They are Arcadia Stationbred horses. The herd moved to us from Glenorchy when the iconic Arcadia Station was sold.

The grey is the stallion who we have named Arcadia Lightning.

They were all unhandled when they arrived on stock trucks and trailers (about 40 horses in total) but settled in very well.

They had excellent feet despite never being trimmed before and have gradually been handled.

Michelle Logan, michelle_dicken@hotmail.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.

Eq Vet Pract March 2022; 47(1) v

The Webinar Vet: learn anytime, anywhere Join the largest online veterinary community in the world ALL VETERINARY PERSONNEL

The NZVA has partnered with The Webinar Vet to offer the New Zealand veterinary profession exclusive memberships tailored to the New Zealand environment. A Webinar Vet membership grants you access to the largest community in the world offering live webinars, Q&A sessions and more.

All webinars offered under this partnership have been CPD accredited by the NZVA and are presented by expert veterinary speakers, so you can be assured that you’ll be completing quality CPD. There are a range of memberships available to suit every veterinary professional in your practice.

MEMBERSHIP OPTIONS Companion Animal & Full Species Weekly Live Clinical Vet Webinars $59/m $590 NZD / annual Companion Animal Nurse Monthly Live Nurse Webinars

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For more information and registrations go to nzva.org.nz/professionals/edhub

NZ EQUINE VETERINARY ASSOCIATION EXECUTIVE COMMITTEE Brendon Bell (President)

nzevapresident@gmail.com

027 484 6378

Katie Kindleysides (Secretary)

nzevasecretary@gmail.com

021 926 3074

Roisin McQuillan (Treasurer)

Lucy Holdaway

Melissa Sim

Andrea Ritmeester (Past President)

Grace Reed

Pip Hendron

Alex Fowler

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

Open

Grooms Scheme

Ivan Bridge ivan@vetassociates.co.nz

Insurance

Brendon Bell brendonb@vetsouth.co.nz

Medication

Andrew Grierson andrew@aucklandvets.co.nz

Website

Open

Young Members

Pip Hendron pip.hendron@swvets.co.nz

LIAISON WITH NZ Equine Health Association

Ivan Bridge ivan@vetassociates.co.nz

NZ Equine Research Foundation

Tim Pearce timpearce@srvs.co.nz

Racing Authorities

Andrew Grierson andrew@aucklandvetcentre.com

Sport Horse

Celia Grant vet@helpmyhorse.co.nz

Eq Vet Pract March 2022; 47(1) vii

2 Eq Vet Pract March 2022; 47(1)

NZEVA PRESIDENT REPORT MARCH 2022 Brendon Bell, NZEVA President nzevapresident@gmail.com

At the time of writing, omicron is winding up so there is a bit of uncertainty ahead. This uncertainty is affecting the 2022 Conference as we make plans for it to be held yet wonder if this will actually happen! The NZVA has put forward a plan B in the form of a virtual conference which is not ideal but perhaps is the best we can do. The keynote speakers have been confirmed but we don’t yet know if they will be able to get into the country and don’t yet know if they will have to isolate once they do. We are all looking forward to the Equine Dinner and the chance to catch up with colleagues. This amount of uncertainty is perhaps part of the ‘coronavirus times’ we are in. Let’s just hope, come June, things will all fall into place.

There is also uncertainty surrounding leadership and direction of the NZVA which is affecting the NZEVA. An NZVA Special General Meeting was held in December, and it seems fair to say that the concerns that invoked this meeting have not as yet been resolved. Input from the Member Advisory Group of which as President I am part of has been sought. At a meeting early in March I will put forward pressing issues concerning equine veterinarians and how the NZVA can help with these; please feel free to contact me to let me know what is important to you. For many of us the veterinary shortage is front and centre and seems to have assumed the number one slot of problems we face. It is pleasing to see recently that the government has made some steps towards making it easier to get equine veterinarians into the country.

In recent discussions with many colleagues about the direction of our parent body there is a worrying trend of NZEVA members questioning the value of NZVA membership.

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.

We can’t have an NZEVA without an NZVA. Once involved in the politics of the NZEVA it becomes apparent that there is an awful lot of behind the scenes work that is done and needs to be done at a political and advocacy level to achieve improvements for our profession. This work can only be done if we have a strong NZVA. Examples of this are legislative changes like who can/can’t perform equine dentistry, horse welfare parameters at events, and pushing to get more vets through Immigration. Such things are necessary and important and don’t just ‘occur’ without someone pushing for it. Please consider the big picture of the veterinary profession when considering whether to renew your NZVA membership; we are certainly better united than divided.

With this in mind, we have two vacancies coming up for executive members of the NZEVA. Andea Ritmeester and Roisin McQuillan are both stepping down this year. If you would like to be part of the NZEVA and want to contribute or make change then please consider offering to join your executive. In the zoom age geographical positioning in the country is no longer an issue so executive membership is open to any member.

I’d like to extend an invitation for anyone who will be at the Karaka Thoroughbred yearling sales to come along to the NZEVA breakfast meeting on the morning of Sunday 6th March. Paul Fraser is our speaker and will be having an interactive discussion on issues around pre purchase.

Kind regards, Brendon Bell nzevapresident@gmail.com

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.

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!

Eq Vet Pract March 2022; 47(1) 3

EDITORIAL BLOG MARCH 2022

I can’t help but start with expressing fond thoughts for our dear friend Lotte Cantley who, as many of you will know, suffered a severe accident involving one of her horses late last year.

I know many of you will have sent Lotte best wishes for a full recovery and I would like to add here further affectionate vibes to her from all EVP readers. As expected, Lotte is remaining positive through this ordeal, but does have a long road to her full recovery. Kia kaha Lotte.

I did try, but got bogged down trying to fathom the science and its interpretation offered by a recent paper on common and rare variations identified in genes in TB racehorses (Tozaki et al. Sci Rep 2021; 11(1): 16057). To my rescue came an interpretive commentary on the paper by Earnest Bailey et al. from University of Kentucky in Eq Dis Q 2022; 31(1): 3.

They concluded that arguably, some of the most important outcomes of this study may be:

•

The information serves as a baseline of diversity to assess and predict changes in the future population resulting from breeding practices.

•

The 12.1 million genetic variants identified among these 101 TBs can be assessed to determine which may cause fitness problems, and which may be desirable for health and racing performance.

•

The data can be applied to assist in detecting inappropriate modifications of DNA by genetic engineering of progeny, called gene doping, done in order to enhance racing performance.

We are all aware that multi-drug resistant bacteria are a huge threat for human and animal health and infections caused by betalactamase-producing Enterobacterales (ESBL-E), are especially troublesome in equine medicine, as only a limited number of appropriate antimicrobial agents are suitable for horses. A study from the University of Helsinki Equine Hospital of 139 ESBL-E isolates from 96 problematic cases of ESBL-E Klebsiella pneumoniae ST307 infections over the period 20112014 (Acta Vet Scand 2022; 64: 4) gave a few pointers as to factors that we might be able to control to help prevent occurrence and spread of such infections. The study found in the multivariable analysis, mare–foal pairs (OR 4.71, 95% CI 1.57–14.19, p = 0.006), length of hospitalisation (OR 1.62, 95% CI 1.28–2.06, p < 0.001) and passing of a nasogastric tube (OR 2.86, 95% CI 1.03–7.95, p = 0.044) were associated with being positive for ESBL-E during the K. pneumoniae outbreak.

Thus, limiting the length of hospitalisation for equine patients may reduce the risk of spread of ESBL-E. Also, as well as

4 Eq Vet Pract March 2022; 47(1)

nasogastric tubing being a potential process for transmitting ESBL-E in hospitalised horses, ESBL-Es were also found in stomach drench pumps used with nasogastric tubes. Thus, veterinary practices should pay close attention to appropriate equipment cleaning procedures and disinfection practices.

Still in a hospital setting for the most part, the merits and failings of rope-assisted recoveries from GA verses free recoveries is well discussed in an evidence based report from Glasgow (Vet Evidence 2021; 6(3): DOI: 10.18849/ ve.v6i3.451), and although it concludes that because there are so many variables one cannot say one system is always best, the discussion is worth viewing to help direct policy for individual practices.

Warwick Bayly from Washington State University presented a nice review of EIPH at last year AAEP Conference. PDF at: (Exercise-Induced Pulmonary Hemorrhage—An Occupational Hazard of High-Speed Exercise. Proc AAEP 2021; 67: 465). A couple of take-home messages taken from the review are that although the proportion of horses affected by EIPH appears to be <10% of the total number of horses racing, it may be that even when EIPH does impair performance, it does so intermittently, and the severity of EIPH tends to worsen as the cumulative number of race starts increase. However, the extent to which an occurrence of EIPH grade ≥3 in an individual horse is predictive of future episodes of equivalent or worse severity requires investigation.

I guess, like me, many a reader of EVP would have been disgusted by the performance of a Kiwi horse trainer in the UK portrayed on national news sites and social media, resulting in the BHA suspending his training licence and setting up an official enquiry. This is the kind of activity that vet Roly Owers, CEO of World Horse Welfare, was talking about when he admonished the equine fraternity to ‘follow the evidence base and continually re-evaluate how they ride and manage horses’ to ensure that horse welfare is always the top priority and that equestrianism is regulated accordingly. The risk of losing our social licence is no empty threat; please take note (Sir) Mark Todd.

Absence of evidence is not the same as evidence of absence.

I was reminded of a clinically important axiom recently by a well-informed clinical epidemiology colleague that we so often neglect. That is that the lack of a statistically significant result

is not equivalent to no clinically significant result, and any interpretation must give due attention to whether confidence intervals support clinically meaningful effects.

We have all had to assist owners in assessing a Horses’ quality of life… and when to call it a day, that being the title of a short discussion paper in Vet Practice columns by last year BEVA President Lucy Grieve. The author offers veterinary advice in helping guide owners through the difficult time that is the end of their horses’ life, and in undertaking an objective assessment, taking into account the horse’s emotional value to the owner whilst also prioritising the physical evidence of ageing.

I used to feel that there was a simple knowledge pyramid, but nowadays we have the variations of ‘low value facts’ we have to deal with daily; even though I do try to discard from my neuron all that is at the bottom of the knowledge triangle.

Even the terms coined for such BS need to be distinguished:

The author found 242 veterinary articles published in 30 (12%) veterinary journals and 132 (82%) animal health journals that were retracted between 1993 and 2019. The estimated rate of retraction increased from 0.03 per 1000 to 1.07 per 1000 published articles with median time from publication to retraction being 478 days (range 0-3,653 days), and more retractions were from veterinary journals than from nonveterinary journals (p = 0.02). Authors or author groups with ≥2 retractions accounted for 37% of retractions and authors from Iran and China together were responsible for ~40% of all retracted articles. Unsurprisingly, authors were affiliated with a faculty of veterinary medicine in 59% of retracted articles. A large proportion of retractions (84%) were research articles, of which 6% were veterinary clinical research papers. Publication misconduct in the form of plagiarism, duplicate publication and compromised peer review accounted for 76% of retractions, compared with unaccountable errors (21%) and research misconduct (18%).

Journals published by societies or institutions were less likely than those from commercial publishers to indicate a reason for retraction. The bald fact is that the rate of retraction in the field of veterinary and animal health has increased by ~ 10fold since 1993, resulting primarily from increased publication misconduct, often by repeat offenders. And this may be only part of the story, Crickey Dick!

Finally, you will find pretty-well all you need to know about guttural pouch disorders in the two papers by our colleagues on pages 31 and 47; read on and learn.

Misinformation = unintentional factual errors.

Disinformation = fabricated or manipulated content/rumours.

Malinformation = inappropriate use of private information.

And scientific veterinary literature is not exempt from such BS as is well shown in a paper on retracted journal articles in veterinary medicine (Christopher MM. BMC Vet Res, 2022; 18(1): 73).

Kia kaha, nā Joe evp.editor@gmail.com

The Illustrated Horse Doctor Ninth Edition. 1876 Edward Mayhew

Chavatte-Palmer P, Derisoud E, Robles M. Pregnancy and placental development in horses: an update. Dom Anim Endocrinol 2022; 79: 106692. https://www.sciencedirect.com/science/article/abs/pii/ S0739724021000874 This review presents recent advances in equine fetoplacental studies, focusing on data obtained by new generation sequencing and progress on the understanding of the role of placental progesterone metabolites throughout gestation.

Further, emphasis is made on fetal programming, a currently very active field, where the importance of maternal nutrition, mare management or the use of embryo technologies has been shown to induce long term effects in the offspring that might affect progeny performance. Finally, new perspectives for the study of equine pregnancy are presented, that will rely on new methodologies applied to molecular explorations and imaging.

Eq Vet Pract March 2022; 47(1) 5

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DATES Available from 4 April 2022 Live discussion dates TBC

Through this course you will gain familiarity with the roles of veterinary responders under the New Zealand Animal Welfare Emergency Management (AWEM) and Coordinated Incident Management System (CIMS) frameworks and develop the knowledge required to assess and manage a large animal rescue safely and humanely. You will learn how to take a leadership role in the management of a disaster situation, how to assess a disaster scene and plan a rescue. Additionally, the course covers how to triage patients, assess the risks on location and safety.

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CPD AREA Technical skills and professional identity.

For more information and registrations go to nzva.org.nz/professionals/edhub

COMMISSIONED REVIEW ARTICLE* MURMURS AND ARRHYTHMIAS IN PERFORMANCE HORSES: WHEN DO WE WORRY ABOUT THESE? PART 2: ARRHYTHMIAS

https://equisense.com/

Katharyn J Mitchell

Cornell University, NY, USA km424@cornell.edu

PART 1 of this paper discussing the practical approach to murmurs in performance horses appeared in the September 2021 issue of EVP.

investigations including echocardiography, ECG analysis (resting and at exercise) and in some cases stress testing under exercising conditions, when some arrhythmias become [most] apparent, and should be evaluated particularly closely.

RECOGNISING AND DESCRIBING ARRHYTHMIAS

INTRODUCTION Cardiac arrhythmias are common findings on physical examination of horses and the difficulty is deciding if you are hearing a normal so called ‘physiological’ arrhythmia such as a 2nd degree atrio-ventricular block (AVB) or a more pathological arrhythmias like atrial fibrillation (AF).1-6 Trying to decide if the arrhythmia is clinically relevant requires experience, interpretation of other historical and physical examination findings and the addition of further diagnostic

When trying to identify the presence of an arrhythmias during a clinical examination, it is important to listen for a reasonable period, at least 30 to 60 sec. Arrhythmias that are paroxysmal or intermittent may be difficult to hear during a short period of auscultation while arrhythmias that occur frequently or are sustained are easier to identify during a clinical examination.

The important features used to describe arrhythmias are listed in Table 3 and features of the most diagnosed arrhythmias and their consequences are listed in Table 4.

Table 3. Points to focus on when auscultating to detect arrhythmias Tachycardic (>44 bpm) Bradycardic (<28 bpm) Normal rate (28-44 bpm)

Rate

Is the background heart rate appropriate?

Rhythm

Is the rhythm regular or irregular?

If irregular, is there a pattern (regularly irregular) or un-patterned (irregularly irregular)?

Irregular rhythms

Are there beats that are faster (premature) or are there pauses?

Are there faster beats followed by pauses?

How long are the pauses? Double normal interval? Shorter? Longer?

Does the arrhythmia appear to go away at higher or lower heart rates?

Do you hear the arrhythmia after exercise?

* These Commissioned Articles are made possible by a generous grant to EVP from Dr Jonathan Hope.

Eq Vet Pract March 2022; 47(1) 7

Table 4. Commonly diagnosed arrhythmias in horses and their hemodynamic consequences.13

Arrhythmia

Auscultation

Consequence

Comments

Clinical signs

2nd degree atrio-ventricular (AV) block

Typically heard at low heart rates.

Considered a normal finding in many horses.

Most often a regularly irregular rhythm (3-4 beats then a pause, twice the normal interval, repeating).

If more than three beats are blocked in a row, or every 2nd beat is blocked for long periods, this is considered abnormal and warrants further investigation.

Commonly heard after sedation with alpha two agonists.

None in normal horses where the 2nd degree AV block disappears at higher heart rates.

If pathological ‘highgrade’ 2nd degree AV block develops and the arrhythmia persists at exercise, then exercise intolerance can be reported.

Disappears at higher heart rates (stress, excitement, exercise) but can be heard during the recovery period as the heart rate decelerates.

Atrial fibrillation (AF)

Premature beats (atrial or ventricular in origin)

8 Eq Vet Pract March 2022; 47(1)

Irregularly irregular rhythm (combination of faster beats, pauses without any clear pattern). Often at rest the heart rate can be normal when averaged over a 3060sec period. Higher than normal heart rates are possible with stress or exercise and the irregularity maybe more difficult to hear.

Loss of atrial booster pump function causes a reduction in cardiac output and results in reduced athletic capacity and poor performance.

A beat that comes earlier than expected.

Often followed by a pause before the normal rhythm resumes. The premature beat can sound louder or softer than the normal beats.

Atrial premature complexes (APC): single APCs are usually of very little hemodynamic consequence, even when occurring at peak exercise, however they act as triggers for the development of AF. Multiple APCs at peak exercise could influence performance.

It is very difficult to determine the origin of the beat on auscultation.

Ventricular premature complexes (VPC): single VPCs are usually of little hemodynamic consequence at rest. If occurring frequently or in multiples at peak exercise an effect on performance could be appreciated. A VPC could act as a trigger for more malignant ventricular arrhythmias (ventricular tachycardia, R-on-T phenomenon, torsade de pointes etc) that could result in collapse or sudden death.

Inappropriately high heart rates (ventricular response rate) during stress or exercise can result in decreased filling time and poor cardiac output.

Wide complex QRS tachycardia can develop during stress or exercise and this can predispose to more malignant arrhythmias that occasionally result in collapse or sudden death.

AF is the most common pathological arrhythmia detected in horses.

It can occur as paroxysmal AF (spontaneous conversion after a short period of time) or can become sustained and require treatment to return to a normal sinus rhythm (NSR).

Reduced athletic capacity and poor performance is commonly reported at higher exercise intensities.

Some horses develop epistaxis if AF occurs during exercise.

It is important to distinguish AF that occurs secondary to underlying structural disease (e.g. atrial enlargement) from that occurring spontaneously in a relatively normal appearing heart, so called ‘lone AF’.

If AF occurs secondary to cardiac enlargement, decompensation and congestive heart failure can develop (jugular vein distension/ pulsation, ventral and limb oedema, ascites, pulmonary oedema, respiratory distress).

An ECG is required to try and determine the origin of a premature beat.

If the arrhythmia burden is high enough during peak exercise, a limitation on performance is possible.

Premature beats occur infrequently at rest in healthy horses (APCs approx. 1-3/hr, VPCs approx. 1/3hrs) therefore auscultation of premature beats during a physical examination is considered clinically relevant.

Premature beats are considered triggers for more complex arrhythmias.

Ventricular arrhythmias pose the biggest concern over safety, particularly when combined with underlying structural heart disease (e.g. as seen in a horse with AR).

Arrhythmia

Auscultation

Consequence

Comments

Clinical signs

Ventricular tachycardia (VT)

Tachyarrhythmia.

The consequences of AIVR or VT depend on a) the rate and b) underlying cardiac or systemic disease c) degree of cardiac dysfunction.

Both AIVR and VT can occur secondary to many systemic diseases or can occur spontaneously. Treatment is indicated for horses that show clinical signs of poor perfusion, rapid heart rate, multiform QRS complexes or show the presence of R-on-T phenomenon or torsade de pointes.

Although occasionally an incidental finding, most horses with AIVR or VT show clinical signs including lethargy, inappetence, colic signs, tachypnoea, jugular distension and/ or pulsation or ventral oedema. Severely affected horses may show weakness, ataxia, or collapse.

Slow VT (also called accelerated idioventricular rhythm or AIVR) can occur at rates of 50-100 bpm.

VT occurs at rates above 100 bpm.

Intensity of beats can fluctuate during auscultation.

Pulse deficits can occur. At higher heart rates, jugular pulsation can be observed.

Typically, clinical signs of poor perfusion occur at rates over 80-100 bpm.

Rapid, multiform (polymorphic) VT, R-on-T phenomenon, or torsade de pointes can rapidly deteriorate into a life-threatening malignant rhythm like ventricular flutter or fibrillation.

ECHOCARDIOGRAPHIC ASSESSMENT AND ECG ANALYSIS While the clinical examination is critical to alert the practitioner to a problem, it is the additional diagnostic evaluation (echocardiography and ECG analysis) that will provide information about the severity, hemodynamic relevance, and likely rate of progression of any cardiac disease present.

A standardised approach to echocardiography and ECG analysis14; 15 is recommended, to assess all the cardiac structures fully. The specific indications for echocardiography and ECG analysis are listed in Table 5.16 Still images and

cineloops should be stored and standardised measurements performed during echocardiography, which will allow comparison of structures over time, particularly important when evaluating the rate of disease progression. Longer duration ECG recordings (often overnight) will be required to determine the importance of intermittent or paroxysmal arrhythmias. Exercising ECGs are essential when assessing the hemodynamic relevance of an arrhythmia and for the risk assessment when determining the safety of a horse during exercise.

Table 5. Clinical findings being indications for echocardiography ± ECG analysis (rest and exercise)16.

Previously diagnosed ‘functional’ murmur that is louder on serial examinations Grade 3-6/6 left sided systolic murmur compatible with mitral regurgitation Grade 3-6/6 left sided diastolic murmur compatible with aortic regurgitation (Grade 2/6 diastolic murmurs when combined with a hyperkinetic pulse) Grade 4-6/6 right sided systolic murmur compatible with tricuspid regurgitation (in a non-athletic breed, a grade 3/6 should also be investigated) Any suspected ventricular septal defect or other congenital heart disease Continuous or combined systolic-diastolic murmurs Any irregularly irregular arrhythmia When premature beats are auscultated When an arrhythmia doesn’t disappear with exercise In a horse with unexplained tachycardia or bradycardia In a horse with a history or clinical signs of weakness or collapse

These data on cardiac chamber size, systolic and diastolic function, valvular and chamber morphology, and the presence of any concurrent arrhythmias, assist in the evaluation of identified cardiac abnormalities as a likely cause (or future cause) of poor performance and for risk assessment when it comes to the question about safety.

SUMMARY Arrhythmias are a common finding in many normal horses, but it is important to recognise those arrhythmias that can result in performance limitation or predispose to an adverse event during exercise.1-3;8 The combination of a murmur and development of a pathological arrhythmia like atrial fibrillation certainly might be very relevant when it comes to performance limitation and should be considered when monitoring for disease progression.

Eq Vet Pract March 2022; 47(1) 9

Far less commonly, a rapidly progressing, severe valvular regurgitation can become hemodynamically relevant, resulting in reduced exercise capacity, poor performance and decrease life expectancy.5; 18; 19

Buhl, R., Carstensen, H., Hesselkilde, E.Z., et al. Effect of induced chronic atrial fibrillation on exercise performance in Standardbred trotters. J Vet Intern Med 2018; 32:1410-1419.

Boegli, J., Schwarzwald, CC., Mitchell KJ. Diagnostic Value of Non-invasive Pulse Pressure Measurements in Warmblood horses with Aortic Regurgitation. J Vet Intern Med 2019;33:1446-1455.

Most (but not all) congenital defects are identified earlier in life, and depending on the severity of the defect, some horses can perform and have a normal life expectancy, while others will develop severe clinical signs and present with exercise intolerance or signs of congestive heart failure.10

Scansen, B.A. Equine Congenital Heart Disease. Vet Clin North Am Equine 2019;35:103-117.

As practitioners, the key is to recognise cardiac abnormalities on a thorough clinical examination, investigate those meeting the criteria for additional diagnostic evaluation and then closely monitor the horse for any change in performance.

Reef, V.B. Evaluation of ventricular septal defects in horses using two-dimensional and Doppler echocardiography. Equine Vet J 1995;27:86-95.

Decloedt, A. Pericardial Disease, Myocardial Disease, and Great Vessel Abnormalities in Horses. Vet Clin North Am Equine 2019;35:139-157.

References Durando, M.M. Cardiovascular Causes of Poor Performance and Exercise Intolerance and Assessment of Safety in the Equine Athlete. Vet Clin North Am Equine 2019;35:175-190.

Mitchell, K.J. ECG interpretation in Equine Practice. CABI International, Oxford, UK. First edition. 2020

Martin, B.B., Jr., Reef, V.B., Parente, E.J. et al. Causes of poor performance of horses during training, racing, or showing: 348 cases (1992-1996). J Am Vet Med Assoc 2000;216:554-558.

Schwarzwald, C.C. Equine Echocardiography. Vet Clin North Am Equine 2019;35:43-64.

Mitchell, K.J. Equine Electrocardiography. Vet Clin North Am Equine 2019;35:65-83.

de Solis, C.N., Althaus, F., Basieux, N. et al. Sudden death in sport and riding horses during and immediately after exercise: A case series. Equine Vet J 2018;50:644-648

Reef, V.B., Bonagura, J., Buhl, R., et al. Recommendations for management of equine athletes with cardiovascular abnormalities. J Vet Intern Med 2014;28:749-761.

Marr, C.M. Equine Acquired Valvular Disease. Vet Clin North Am Equine 2019;35:119-137.

Trachsel, D.S., Schwarzwald, C.C., Bitschnau, C., et al. Atrial natriuretic peptide and cardiac troponin I concentrations in healthy Warmblood horses and in Warmblood horses with mitral regurgitation at rest and after exercise. J Vet Cardiol 2013;15:105-121.

Leroux, A.A., Detilleux, J., Sandersen, C.F., et al. Prevalence and Risk Factors for Cardiac Diseases in a Hospital-Based Population of 3,434 Horses (1994-2011). J Vet Inten Med 2013;27:1563-1570 Patteson, M.W. and Cripps, P.J. A survey of cardiac auscultatory findings in horses. Equine Vet J 1993;25:409-415.

Reef, V.B., Bain, F.T. and Spencer, P.A. Severe mitral regurgitation in horses: clinical, echocardiographic and pathological findings. Equine Vet J 1998;30:18-27.

Keen, J.A. Examination of Horses with Cardiac Disease. Vet Clin North Am Equine 2019;35:23-42.

Reef, V.B. and Spencer, P. Echocardiographic evaluation of equine aortic insufficiency. Am J Vet Res 1987;48:904-909.

AAEP INFECTIOUS DISEASE GUIDELINES AAEP guidelines are created to provide instruction about horse health topics for the practitioner and the equine industry. A full listing is available HERE. Below is access to downloadable PDF guidelines for those diseases pertinent to Aotearoa NZ.

•

Botulism (Clostridium botulinum)

•

Rhodococcus equi

•

Clostridial diarrhea/enteritis

•

Rotavirus

•

Equine Coronavirus (ECOV)

•

Salmonellosis

•

Equine Herpesvirus (EHV-1 and EHV-4)

•

Strangles (Streptoccocus equi)

•

Equine Parvovirus-hepatitis Virus (EqPV-H)

10 Eq Vet Pract March 2022; 47(1)

CASE REPORT PARAPHIMOSIS IN A MALNOURISHED STALLION Margaret Leyland & Erin Simpson admin@vor.co.nz

CASE HISTORY A 6-year-old sports horse stallion was presented due to inability to retract the penis, which was swollen below the preputial ring (Figure 1). The horse had a body condition score of 1/5 (Carroll CL, 1988) was quieter than expected, and the testicles were not visible or palpable within the scrotum. Otherwise, no abnormalities were detected on clinical examination.

then 1 g PO, BID). The penis was bandaged and supported against his ventral abdomen with a sling made from two pairs of 40 denier tights.

After 24 hours, there was some reduction in swelling, however, the epithelium of the penis had started to excoriate due to friction and urine-scalding. Even after massage, it was not possible to replace the penis fully within the sheath (Figure 2). After 48 hours, and further massage, it was possible to manually replace the penis inside the sheath, however, the sling was not able to keep it in place. A probang (repulsion device) was constructed and held in place with Elastoplast around the abdomen(Koch, O’Brien, & Livesey, 2009). This had the advantage of keeping the penis within the sheath where it seemed much less vulnerable to urine-scalding (Figures 3 & 4).

Figure 1: Penis at presentation showing swelling between the preputial ring and the attachment of the preputial lamina.

Initial treatment aimed at removal of the underlying cause and penile support. The horse was given an anthelmintic and moved to a property where he could be closely monitored and fed properly. Phenylbutazone was administered (2 g IV

Figure 2: Penis after 3 days of supportive treatment.

Eq Vet Pract March 2022; 47(1) 11

Figure 3: Equipment required for construction of a penile probang (Koch, O’Brien, & Livesey, 2009).

Partial penile amputation was performed at Massey University Veterinary Teaching Hospital by the modified Williams’ technique (Williams, 1943). The majority of the penis was removed to leave a large triangular urethral opening positioned pointing downward (to reduce the risk of stricture) just beyond the end of the prepuce. Penile vessels were ligated (Ligasure™) and electrocauterized to minimise bleeding. The urethral mucosa and dorsal aspect of the penile stump were reconstructed using absorbable suture material.

Recovery was successful, though it was felt that the fact that the horse was still a stallion contributed to the frequency of post-operative bleeding secondary to erection. For this reason, the general recommendation is to perform castration before or at the time of penile amputation (Schumacher, 2006). In this case, the horse had been rehomed and the new owner wanted to ensure that the penile amputation was successful before investing further in castration.

The horse has since been castrated and has been broken in, and the owner reports satisfaction with the cosmetic result and his ability to urinate (Figure 6).

DISCUSSION

Figure 4: Application of the penile probang.

Initially the penile probang would stay in place for up to a week at a time, though as the horse gained condition and energy it was becoming dislodged more frequently. There was some improvement in penile tone, and sensory innervation of the penis was evident. However, after eight weeks with the probang, he was still not able to fully retract the penis himself, and there did not seem to be any further improvement (Figure 5). The decision was made to refer for penile amputation.

12 Eq Vet Pract March 2022; 47(1)

Paraphimosis is defined as inability to retract the penis into the prepuce. Possible causes include trauma (especially during breeding in stallions), complication of surgery (usually castration), phenothiazine tranquilisers (Wagner, 2009), EHV-1, rabies, as a sequel to priapism, secondary to ventral oedema, and exhaustion or severe debility; the latter being well recognised as a common problem in horses on the western front in WW1 (Hobday, 1938).

In the current case, there were no signs of primary trauma to the penis. There was no history of systemic illness, surgery or sedation, no reason for exhaustion, no oedema other than of the penis, and no known history of priapism. It was felt that the most likely cause of paraphimosis was malnutrition.

Figure 5: Progression of the state of the penis after 2 days (A), 17 days (B) and 53 days (C) of supportive treatment.

exercise, hydrotherapy, ultrasound-guided drainage of fluid pockets (Brinsko et al., 2007), and application of leeches (Nowicki, 2021).

A modified Buhner technique has been used successfully to retain the penis within the prepuce (Aurich & Aurich, 2006).

However, this method causes further trauma to an area that is already compromised (Koch, O’Brien, & Livesey, 2009).

We found that use of the penile probang greatly simplified treatment in that it was easy to construct and apply, welltolerated, removed the need for daily massage, and reduced trauma to the penis (Koch, O’Brien, & Livesey, 2009).

Figure 6: The horse 8 months later in good health having gained considerable body weight.

Once paraphimosis occurs, the problem is likely to be perpetuated by the vulnerability of the penis to external trauma and the forces of gravity which impair lymphatic and venous drainage. This results in oedema which increases the weight and size of the prolapsed penis, causing muscle fatigue and potentially pudendal nerve damage. Consequently, penile support is essential to decrease swelling, protect the penis, and allow recovery of the muscles and nerves.

In addition to removal of underlying causes and penile support, other suggested treatments include NSAIDs, corticosteroids, topical DMSO, antimicrobials, controlled

The prognosis for resolution of paraphimosis is generally very good in acute trauma cases. The prognosis in debilitated horses is less favourable due to the underlying causes. In a case series of paraphimosis in seven debilitated horses (Simmons et al., 1985), one died, three were euthanised, two were discharged with partial paralysis and one with complete paralysis. Where the cause of debility is reversible, paraphimosis may also be reversible. However, partial resolution may occur due to fibrosis and/or irreversible nerve damage. This was assumed to be the reason for failure of full resolution in the present case. Interestingly, stallions seem to be over-represented even when paraphimosis is secondary to debility as there were only two geldings out of seven horses in this series.

It was interesting to note the testes were non-palpable at initial presentation. There is evidence of an association between malnutrition and decreased testicular size in humans (Handelsman & Staraj, 1985). In the current case, testicular atrophy was grossly reversible, though we do not know what the effect on fertility would have been due to penile amputation and castration.

In conclusion, paraphimosis is an uncommon presentation in New Zealand equine practice. It can be successfully managed when recognised early and if the underlying cause is reversible. In some cases, however, the horse may not be salvageable as a breeding stallion.

Eq Vet Pract March 2022; 47(1) 13

References Aurich J and Aurich C. Treatment of penile prolapse in horses using a modified Bühner suture technique. Vet Rec 2006; 159(15): 491-2 Brinsko S, Blanchard TL and Varner DD. How to treat paraphimosis. AAEP Annual Convention – Orlando. 2007 Carroll CL and Huntington PJ. Body condition scoring and weight estimation of horses. Equine Vet J 1988; 20: 41–45.

Handelsman D & Staraj S. Testicular size: the effects of aging, malnutrition, and illness. J Androl 1985; 6(3): 144-151.

Hobday, F. Fifty years a veterinary surgeon. London: Hutchinson and Co. Ltd. 1938 Koch C, O’Brien T and Livesey MA. How to Construct and Apply a Penile Repulsion Device (Probang) to Manage Paraphimosis.

AAEP. 2009.

14 Eq Vet Pract March 2022; 47(1)

Nowicki A, Jaworska J and Baranski W. Leech therapy in the treatment of a penile haematoma in a stallion. Veterinární Medicína 2021; 66(No. 6): 266–271.

Schumacher J. Penis and prepuce. In Auer J and Stick J (eds), Equine Surgery, 5th Ed, Ch 61. St Louis, MO: Saunders Elsevier.

2018: 1034-1064.

Simmons H A, Cox JE, Edwards GB, Neal PA and Urquhart KA. Paraphimosis in seven debilitated horses. Vet Record. 1985; 116(5): 126-7 Wagner A. The Case Against the Use of Acepromazine. AAEP Convention Proceedings. 2009.

Williams WL. The Diseases of the Genital Organs of Domestic Animals. Ithaca, NY. 1943.

Acknowledgements Thanks to the staff at Massey Equine for caring for the horse and especially to Allison Aldrich for performing the surgery.

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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. Welcome and introduction - Nick Wingfield Digby 2. Sales selection - The trainer’s view point - Sir Mark Prescott 3. The Sales Exam - The veterinary viewpoint - Mike Shepherd 4. Do foal injuries and diseases compromise sales and racing performance - Celia Marr 5. Radiography at the Sales - Are findings associated with future performance Pt1 - Debbie Spike-Pierce 6. Radiography at the Sales - Are findings associated with future performance Pt2 - Debbie Spike-Pierce 7. Does conformation affect gait - Objective assessment Renate Weller 8. 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. Radiographic findings in Juvenile Orthopaedic Disease Debbie Spike Pierce 2. Soft tissue injuries of the foot are there red flags on plain radiography - Marianna Biggi 3. Has advanced imaging changed the management of proximal suspensory desmitis - Sue Dyson 4. Imaging & clinical management of suspensory branch injury in racing thoroughbreds - Pete Ramzan 5. Third phalangeal cysts in the Thoroughbred Racehorse - Tom O’Keeffe 6. Imaging the equine back - Marianna Castro Martins 7. Fractured ribs - Diagnosis and prognosis - Billy Fehin 8. Pelvic ultrasonography - Sarah Boys Smith 9. Sub clinical imaging findings in the elite sport horse - How do we determine relevance - Sue Dyson

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CASE NARRATIVE BOVINE AMNION HASTENS WOUND HEALING? Julie Bell

Southern Rangitikei Veterinary Services julie@srvs.co.nz

On July 14, 2021, a TB yearling was found in the paddock with a large wound on his dorsolateral forearm just above the carpus. The yearling had been checked 24hrs previously and the state of the wound tissues indicated that the injury had occurred soon after that check.

Upon inspection, the wound was very deep, transecting the common digital extensor as well as various other soft tissues in the area. The yearling was unwilling to move but was able to mobilise the limb with mild knuckling when forced to move and was able to bear some weight on the limb at rest. The carpus joint did not appear to be involved. The wound was cleaned, flushed, debrided, and bandaged and the yearling was placed on gentamicin, penicillin and phenylbutazone at standard dose rates; the patient had been recently given a tetanus booster vaccine. Due to budget constraints and knowledgeable owners the yearling was left for the owners to medicate over the weekend.

The yearling improved over the weekend and the following week. As expected, further debriding was performed on the second visit after more soft tissue died away. When revisited the following week it was clear that the stump where the tendon was transected was not granulating in, likely due to constant movement of the region. There was an area above the stump that needed additional debridement but was granulating sufficiently.

It was at this point that it became evident that further intervention may be needed for this wound to heal. The goal was to help bring extra nutrients to the area to increase healing yet still stay within the budget constraints of the clients. Articles about the use of equine amnion as a biological dressing in equines sounded promising. As it was not foaling season this did not seem that practical but since the owners (dairy farmers) had just begun calving it was decided that it was worth trying bovine amnion instead. Annette McCoy’s 2017 AAEP presentation on amnion as a wound dressing was extremely helpful. In this short presentation she describes two very simple methods of preparing the amnion. The owners were willing to give it a go and collected the cleanest, freshest, bovine amnion they could find - within 1hr of calving - and dropped it into the clinic. There were two methods of processing described by McCoy (2017) but the Iodine method of preparation, as shown in text box, was more suitable due to individual time restrictions.

IODINE/ACETIC ACID PROTOCOL 1. Cut off areas with ground-in debris and rinse the amnion with gentle agitation under cool tap water to remove gross debris.

2. Cut the amnion into multiple pieces depending upon the size of dressings needed. Note that the protocol does this after processing, but it was easier to work with smaller pieces.

3. Place amnion in a 2% povidone iodine solution, gently agitate and refrigerate for 24 hours. Saline bottles were ideal for making the solution and then storage.

4. After 24 hours refrigeration, rinse the amnion 3 times in sterile saline and once in 0.25% acetic acid (regular vinegar diluted down) 5. Refrigerate the dressings in 0.25% acetic acid until use (up to one year).

The amnion was placed under the bandage and the bandage was changed every 7 days or as needed with a new amnion dressing placed each time. The owners did this themselves unless a vet was already present on the farm for another case.

The wound made significant improvements over this time as seen in the photos. The area that contained the tendon stump began to form a much healthier tissue bed and granulated into the area above it. Photos of the progress are shown below. As with any injury it is impossible to know if the amnion treatment had any effect on the progress or if the amnion was placed coincidentally at the time that the wound was about to produce more healthy tissue and significantly improve itself. It is to be noted that this wound was on the upper limb which does tend to heal better than the distal limb. However, the treatment was cheap and easy and definitely did no harm. It also left a very positive impact with the owners.

Amnion has been used on wounds since as far back as the 1900’s in both human and veterinary medicine. Amnion tissue contains many biological molecules and growth factors that are beneficial to wounds by promoting tissue growth and healing. It is also recruits the body’s own stem cells to the wound. It is thought to be especially helpful in contraction of chronic wounds for this reason. Equine amnion in comparison

Eq Vet Pract March 2022; 47(1) 17

Figure 1: Progress in wound healing by days from initial injury. A, 14 days - the wound had been debrided 2 days previously; B, 19 days - the day before amnion treatment began and the last time the wound needed debridement. C, 31 days; D, 66 days – about 2 months from initial injury, the patient being sound and the wound healing well.

to other species is particularly useful as a wound dressing due to a thicker connective tissue layer and, if the timing fits, is potentially a better choice than bovine amnion.

As outlined above the iodine/acetic acid protocol was used in this case but there is also a dilute chlorhexidine protocol that can be followed. Both are simple and require no expensive equipment. Following the protocol is important to reduce the likelihood of introducing a pathogenic bacteria to the wound but also to preserve the protein content within the amnion.

Using hot water or harsher antiseptics can disrupt this protein and reduce the efficacy and wound healing benefits of the dressing. Studies on both the reduction of bacteria following processing and the integrity of proteins and structure following processing and storage have been done on more than one occasion.

It is hard to base a lot of belief on the results of one case.

However as mentioned above the dressing was cheap and easy to use. The owners were very positive about the process and the wound appeared to make significant improvement coinciding with the start of the amnion dressing application. It would be interesting to use this treatment again in the future, especially on some challenging chronic distal wound cases that often prove to be challenging and frustrating.

Reference McCoy AM. How to Prepare and Store Equine Amnion for Use as a Biological Wound Dressing. Proc AAEP Ann Conv 2017; 63: 200-2005. Audio available at https://aaep.digitellinc. com/aaep/sessions/1878/view with registration; accessed 04_11_2021.

KESTER NEWS HOUR AAEP 2021 VIRTUAL ISSUE https://beva.onlinelibrary.wiley.com/doi/toc/10.1001/(ISSN)2042-3306.Kester.News.Hour.and.Milne.Lecture.AAEP.2021

These papers from EVJ and EVE were discussed at the Kester News Hour during the Annual Convention of the American Association of Equine Practitioners, December 2021 and are available HERE as Open Access or Free-To-Read papers • Radiological prevalence of osteoarthritis of the • Detection of synovial sepsis in horses using enzymes cervical region in 104 performing Warmblood jumpers. as biomarker. Haralambus R et al.

Espinosa-Mur P et al.

• Active immunisation against GnRH as treatment • Caudal cervical vertebral morphological variation is not for unilateral granulosa theca cell tumour in mares. associated with clinical signs in Warmblood horses. S. Behrendt D et al.

Veraa et al.

• Deep digital flexor tendon lesions in the pastern are • Factors associated with survival and racing associated with the presence of distal tendinopathy. performance of 114 Thoroughbred foals with septic Acutt EV et al. arthritis compared with maternal siblings (2009-2015). • Current joint therapy usage in equine practice: O’Brien TJ et al Changes in the last 10 years. Zanotto GM and Frisbie DD.

18 Eq Vet Pract March 2022; 47(1)

NZ EQUINE RESEARCH FOUNDATION As many of you are aware the NZ Equine Research Foundation Inc (NZERF) was established in 1977 to foster education of and research for the NZ Horse Industry. In 1981 the NZERF was registered as a Charitable Trust.

Over the years NZERF has funded many research projects and has promoted and expanded public knowledge by conducting seminars, releasing videos and publishing bulletins and booklets. Several Scholarships are also available, two of which are specifically available to Veterinarians. The Jonathan Hope Equine Veterinarian Scholarship is available to help ‘young at heart’ equine practitioners travel, either nationally or internationally, to ‘see practice’ and improve their practical skills whilst the Veterinarian/Farrier Scholarships are available for Vets & Farriers from the same geographical area to spend time at a suitable course and/or with colleagues in a suitable practice.

The NZERF Board is made up of nominees or co-opted members of the racing codes, breeder organisations, equestrian sport and pony clubs, and Massey University.

In addition, we have had strong support and participation from NZEVA and Veterinarians in Equine practices.

Covid has had some impact on NZERF activities with the popular Lecture series being on hold and Scholarship

winners not being able to travel overseas.

We appreciate the assistance that practitioners provide by making their clients aware of our publications and having copies available to pass on to them. To facilitate this, we send supplies to several practices. If you have not received copies of our bulletins or require additional copies, please contact our office: nzerf@xtra.co.nz or 021 555 954. Details of booklets still available will be set out on our website when it is updated in the next little while.

There is no charge for the publications but as a Charitable Trust we welcome donations.

We are attempting to build up a library of short videos.

These are most suitable for client evenings.

Please continue to promote NZERF activities and its publications to colleagues and clients. Doing so will promote better knowledge of the horse.

If you require any clarification on any activities of NZERF please do not hesitate to make contact.

Tim Pearce Chairperson NZERF timpearce@srvs.co.nz

BRIAN GOULDEN AWARD

New Zealand 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 nomination 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 ANT TIME to nzevasecretary@gmail.com.

Brendon Bell NZEVA President

nzevapresident@gmail.com

Eq Vet Pract March 2022; 47(1) 19

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CASE REPORT CERVICAL OESOPHAGEAL RUPTURE IN A PREGNANT MARE. Shaan Mocke

S.Mocke@massey.ac.nz

Gareth Fitch

leefitch@cityu.edu.hk

SUMMARY Successful resolution of a case of oesophageal rupture with Horner syndrome in a late-term mare was achieved with surgery, insertion of a temporary indwelling oesophagostomy tube and enteral feeding.

JoAnna Faircloth

Dr.joannafaircloth@gmail.com

was administered intravenously at a dose rate of 4.4 mg/ kg and dimethyl sulfoxide applied topically. The owner was instructed to keep her in a yard overnight and monitor comfort, water intake and appetite. The following day, clinical signs worsened. The swellings had increased in size, and the owner reported that the mare had nasal discharge and an unusual sweating pattern around her head.

EXAMINATION FINDINGS On presentation at the clinic, she was more lethargic than the day before, there was bilateral green nasal discharge, moderate tachycardia, 55bpm, and pyrexia, 38.90C. There was increased swelling and diffuse cellulitis in the ventral aspect of the caudal third of the neck. The swelling was painful on palpation; however, the mare was able to move her neck normally. The sweating pattern round her head was unilateral (left side only) and was combined with a left-sided ptosis (upper eyelid droop), and left-sided muzzle droop, indicative of Horner syndrome (Figure 2).

Figure 1: Soft tissue swellings seen on left neck at first visit.

SIGNALMENT AND HISTORY A 7-year-old standardbred broodmare was reported by the owner to be dull and had separated herself from the broodmare herd. She was primiparous and due to foal in 6 weeks’ time. She was initially examined in the field, and was quiet, but still alert and responsive. On physical examination the mare was mildly tachycardic, other parameters were within normal limits, including her temperature.

She had several soft-tissue swellings located on the lateroventral aspect of the caudal third of her neck (Figure 1) which were warm to the touch. There was no evidence of external trauma. She had been observed drinking and ate grass that was offered without hesitation. Phenylbutazone

Figure 2: Left unilateral sweating of the face with ptosis, consistent with Horner syndrome.

Eq Vet Pract March 2022; 47(1) 21

DIAGNOSTIC FINDINGS The blood results from the first day revealed leucocytosis, due to a moderate neutrophilia [16.4 x 109 /L] with a left shift [8% band neutrophils]. There was a moderate increase of fibrinogen [50 g/L] and SAA was increased [1278.6 µg/ml] An endoscopic examination was performed, and she had a left-sided laryngeal hemiplegia (grade 3.1 on the Havemeyer scale), and some pooling of food in the oesophagus. There was also a section of the oesophagus, ~3 cm in length, that was compressed halfway down the neck. The oesophagus itself appeared normal oral and aboral to the area of compression.

Ultrasound of the neck showed significant swelling of subcutaneous tissue along with hyperechoic material outside the lumen of the oesophagus. The jugular vein was normal.

Cervical radiographs were taken before and after feeding of (Iohexol™), The radiographs indicated that there was food material outside of the oesophageal lumen, i.e. an oesophageal tear (Figure 3) Figure 4: Oesophagostomy tube in place.

SURGICAL PROCEDURE

Figure 3: radiograph showing gas and food material in the soft tissues adjacent to the oesophagus.

TREATMENT PLAN Based on the findings, the mare was diagnosed with cervical oesophageal rupture, presumed to be secondary to an oesophageal obstruction. Both the mare and foal had commercial and sentimental value and the owner was interested in saving both the mare and foal. A guarded prognosis was given for both short and long-term survival.

It was decided to perform surgery to allow lavage of the contaminated tissues and place an oesophagostomy tube for feeding for sufficient time to allow the oesophagus to heal by second intention. The procedure was to be performed under general anaesthesia.

22 Eq Vet Pract March 2022; 47(1)

Prior to induction of anaesthesia, a nasogastric tube was passed down the oesophagus to assist with the surgical approach. An incision was made using a ventrolateral approach, distal to site of rupture. A 10cm long incision was made through the skin. The sternocephalicus and brachiocephalicus muscles were separated, and the deep cervical fascia incised to expose the oesophagus. Two longitudinal tears were noted. A large amount of food material had dissected through the fascial planes but did not extend into the mediastinum and thoracic cavity. The food material was removed by lavaging the area with 1:40 dilute povidone iodine solution delivered via a stomach pump and a small nasogastric tube. To allow passage of a feeding tube into the oesophagus distal to the tear, a smaller bore nasogastric tube was placed inside a modified, shortened standard diameter nasogastric tube. The smaller tube was then passed into the distal oesophagus as a guide and then the larger tube passed over this into the stomach, the smaller tube was withdrawn.

A Chinese Finger Trap suture was used to secure it in place during recovery.

Broad spectrum antimicrobial therapy was commenced with the mare receiving 22 mg/kg intravenous sodium penicillin three times daily, 6.6 mg/kg intravenous gentamicin once daily and 15 mg/kg enteral metronidazole three times daily. For pain and inflammation, she received flunixin meglumine at doses of 0.5-1.1 mg/kg at 8-12 hourly intervals, either intravenously or orally.

Omeprazole was administered initially at 4 mg/kg PO, reducing to 2 mg/kg after 2 weeks plus ranitidine at 6.6 mg/ kg PO for the first week. Altrogenest (Regumate™, MSD Animal Health) was administered at 22 mg/kg to help maintain pregnancy. Penicillin and gentamicin were discontinued after 9 days and metronidazole was discontinued after 14 days based on bloodwork results.

Feed was enteral only administered via the oesophagostomy tube (Figure 4) and each feed consisted of a slurry of high protein feed given five times daily. The composition of each feed for the first two days was: 100 g of a protein and energy supplement (Rebuild™, Prydes, Aus), 600 g of EasiSport™ (Prydes, Aus), 40 g NaCl, 50 mL rice bran oil and vitamin E as Nano-E™ (Kentucky Equine Research, KY, USA). The feed was pre-soaked in warm water for a minimum of one hour prior to feeding. After two days the Rebuild™ was increased to 250 g and the EasiSport™ to 700 g, and the NaCl was decreased to 25g and the rice bran oil to 15 mL. The total volume per feed was not to exceed 7 L, which included additional water administered to flush the tube. The feeding times were spaced 3-4 hours apart. Prior to feeding the mare would be checked for any reflux, if any was present this feed would be missed until the next scheduled feed. Blood electrolytes were monitored for the first few days (i-STAT Handheld, Abbot) to allow compensation for salivary loss.

Every seven days a gastroscope was passed to assess healing of the oesophagus. The cavity surrounding the oesophagus reduced with formation of granulation tissue until there was a functional oesophageal lumen. The feeding regimen was maintained for a total of three weeks at which time the oesophagostomy tube was removed. The oesophagostomy site surrounded by granulation tissue was allowed to close by second intention. The mare could graze and was able to swallow normally with only a small amount of grass-tinged saliva exiting the site. At this stage she was fed 100 g of Rebuild™, 600 g of EasiSport and 200 g of Biomare (Prydes, Aus) and 10 mL rice bran oil per feed, five times daily. Salt was reduced to 20 g NaCl in two of the feeds only as there was reduced salivary loss.

The mare was discharged to a local stud farm one week prior to her foaling date, with a body condition score of 6/9.

Discharge instructions included grass and soaked feed diet only with no hay or haylage, a separate paddock and access to a salt lick.

OUTCOME The oesophagostomy site granulated in within several days.

She did not have any problems eating and was not attended for choke. There was some concern over swelling at site, but this appeared to be associated with superficial scar tissue.

Two weeks after discharge, the mare produced a healthy foal (Figure 5). Both mare and foal were reported to be doing well and the mare has subsequently produced another foal.

Figure 5: Mare with foal, both doing well.

DISCUSSION Disorders of the oesophagus include stricture, obstruction, external mass, neoplasia, diverticulum formation and rupture (Bedezkoya 2012, Stick 2012). Oesophageal obstruction (choke) is commonly seen in equine practice with clinical signs such as distress, dysphagia, food material at the nares, coughing, ptyalism (saliva), and palpable lumps along the left neck (Bezdekova2012, Archer 2013).

Oesophageal rupture is an uncommonly reported disease with a poor prognosis with non-surgical management (Whitfield‐ Cargile 2013, Craig 1990). There are reports of cases of cervical oesophageal rupture managed successfully following surgical intervention and alimentation via an oesophageal tube placed via the wound or separate oesophagostomy or naso-oesophageal tube (Whitfield-Cargile et al. 2013).

Rupture can occur secondary to long-standing obstruction, repeated or aggressive nasogastric tube passage, foreign body perforation, external trauma such as a kick to the neck, or extension of infection from surrounding structures (Bezdekova 2012). Obstruction can cause pressure necrosis to esophageal mucosa which can rupture, with ingesta leaking into the soft tissues of the neck causing severe infection.

Contrast radiography was used to confirm that an oesophageal rupture had occurred. Iodinated contrast medium (Iohexol™), was chosen instead of barium as the latter is contraindicated in suspected perforations as it is irritant to extra oesophageal tissues (Koskinen 2015).

Eq Vet Pract March 2022; 47(1) 23

Secure closure of a ruptured or perforated defect is usually possible only in patients operated on shortly after (< 12 h) perforation has occurred (Stick 2012). In early cases, when esophageal tissues are too damaged to hold sutures or when infection or contamination with ingesta has already occurred, some means of draining the esophageal contents to the outside must be provided (Stick 2012).

For much of the cervical portion, the oesophagus is accompanied by the recurrent laryngeal nerves and by the left common carotid artery and its accompanying vagosympathetic trunk in the carotid sheath. It receives its innervation from the cervical sympathetic supply and from the vagus nerves, including the recurrent laryngeal branches; the vagal supply being the most important for motility.

Trauma, peri-jugular injections, abscesses and cellulitis involving the cervical sympathetic trunk can result in Horner syndrome. The classic signs of Horner syndrome are unilateral ptosis (upper eyelid droop and lowered eyelash angle) and miosis, along with ipsilateral facial sweating, and must be distinguished from facial paralysis (Palumbo 2011).

Laryngeal hemiplegia will only accompany Horner syndrome if the recurrent laryngeal nerve is affected also (Palumbo 2011).

Perhaps most commonly, Horner syndrome is caused by an inadvertent extra-jugular injection and will usually have a good prognosis if the offending compound is not too irritant. The mare in this report had not received any intravenous injections prior to being seen, so this was an unlikely cause of the nerve damage that was almost certainly due to the inflammation of the nerve due to leakage of ingesta and saliva from the rupture site.

Formation of a stoma caudal to the rupture site has been advocated to avoid delayed healing at the site of the rupture (Whitfield-Cargile 2013, Stick 2012), but in this case the rupture occurred at a distal cervical location making creation of a separate incision site caudal to this difficult. The indwelling tube was placed through the distal portion of the oesophagus at the site of the rupture which has been reported to not have any deleterious effect on healing (Leus and Rasmussen 2021, Whitfield-Cargile et al. 2013). Placement of the tube in a standing horse has been described, but int this case general anaesthesia was chosen due to the degree of contamination.

It could be argued that a standing procedure would be indicated in a late term mare. It is preferable to leave the tube in place for 7-10 days until granulation forms around the tube to form a fistula (Craig 1989; Freeman 1989; Risnes and Mair 2003; Whitfield-Cargile et al. 2013). In cases of enteral feeding via a nasogastric tube, the tube is left in place until healing is sufficient to allow removal. The tube can be removed between feedings, but once granulation is established the stoma can contract very rapidly making passing of the tube complicated and potentially lead to trauma. In the case of this mare, the tube was left in place for three weeks. In cases of dysphagia due to guttural pouch mycosis, a nasogastric tube has been maintained for much longer periods with no apparent complications. Reported complications include accidental tube removal, oesophageal irritation, development

24 Eq Vet Pract March 2022; 47(1)

of strictures or diverticula at the site, recurrence of the obstruction, postoperative infection, laryngeal hemiplegia and even carotid artery rupture (Waguespack 2007, Risnes and Mair 2003). The stoma generally heals spontaneously after the tube is removed, with fistula formation being rare (Whitfield-Cragile et al. 2013, Stick 1981).

The neutralising effect of alkaline saliva is lost initially as significant portion of saliva exits the stoma and it is likely that the indwelling tube passed through the cardiac sphincter, although this was not confirmed in this case, which could potentially lead to reflux of gastric contents into the oesophagus. In an attempt to reduce the likelihood of reflux oesophagitis and gastric or oesophageal ulcer formation anti-ulcer medication was used initially. Positioning of the tube within the stomach as apposed to the distal oesophagus reduces the likelihood of dislodgement of the tube (Stick 1981).

Enteral feeding via an oesophagostomy tube in a Quarter horse with an oesophageal rupture has been described in detail (Read et al. 2002), but this is the first report of complete enteral feeding via an oesophagostomy tube in a late gestation mare. Complete enteral feeding via an oesophageal tube is relatively intensive if body condition is to be maintained because it requires feeding at least 5 times a day over a period of many days. The diet in this case was based on estimation of the body weight and energy requirements according to published data (Anderson 2011). This case report demonstrates that it is possible to maintain a mare in late gestation with gastric feeding alone for three weeks and maintain sufficient body condition for tissue repair, and to maintain the pregnancy through until parturition and lactation.

The diet was formulated from commercially available feeds supplemented with oil and electrolytes and preparation of the feed is straightforward in that it does not require maceration or blending. No patch was created to cover the stoma during healing as there was minimal leakage of food or water and so it was not deemed necessary. The mare did not have problems with recurrent obstruction and so endoscopic examination of the oesophagus was not performed. Thus, the possibility of formation of a degree of stricture or of a traction diverticulum remained (Whitfield-Cargile et al. 2013), although it was assumed that if there were such complications, there would have been clinical signs during recovery. This mare was fortunate that the food had not dissected distally through the fascial planes and into the thoracic cavity. If there had been infiltration of feed into the mediastinum no attempt would have been made to save the mare due to the poor prognosis for survival.

This case serves to illustrate the clinical signs, diagnosis and management of a cervical oesophageal rupture and to add to the number of cases successfully treated with surgical management.

REFERENCES Anderson, K. (2011). Nutrition management of pregnant and lactating mares; EC285. Extension Division University of Nebraska. PDF at: https://extensionpublications.unl.edu/ assets/pdf/ec285.pdf Archer, D. C. (2013). Handbook of Equine Emergencies E-Book. Elsevier Health Sciences.

Auer, J. A. & Stick, J. A. (2018). Equine Surgery-E-Book.

5th Ed. Elsevier Health Sciences.

Bezdekova, B. (2012) Esophageal disorders in horses – a review of the literature. Pferdeheilkunde 28, 2, (March/April) 187-192.

Butler, J. A., Colles, C. M., Dyson, S. J., Kold, S. E. & Poulos, P. W. (2017). Clinical radiology of the horse 4th Ed. John Wiley & Sons.

Craig, D.R., Shivy, D.R., Pankowski, R.L. and Erb, H.N. (1990).

Esophageal disorders in 61 horses: results of nonsurgical and surgical management. Veterinary Surgery 18(6): 432-438.

Koskinen, M. J., Hewetson, M., & Pöytäkangas, M. R. (2015). Iohexol as a Marker of Intestinal Permeability in the Horse. Equine Veterinary Journal, 47, 8-8.

Leus, E. K. and P. Randleff-Rasmussen (2021), Management of oesophageal rupture by tube feeding through the oesophageal wound. Equine Veterinary Education 33 (7), 192-196.

Palmers, K., Van der Vekens, E., Paulussen, E. et al.

(2016). Radiographic and ultrasonographic evaluation of the esophagus in the horse. Vlaams Diergeneeskundig Tijdschrift, 85(2), 78-86.

Palumbo, M. I. P., Moreira, J. J., Olivo, G. et al. (2011).

Right‐sided laryngeal hemiplegia and Horner’s syndrome in a horse. Equine Veterinary Education, 23(9), 448-452.

Read, E. K., Barber, S. M. Wilson, D. G. Bailey J. V. & Naylor J. M. (2002) Oesophageal rupture in a Quarterhorse mare: unique features of liquid enteral hyperalimentation and fistula management. Equine Veterinary Education 14 (3) 126-131, Risnes I. & Mair, T. S. (2003), Traumatic oesophageal rupture in a horse complicated by subsequent rupture of the common carotid artery. Equine Veterinary Education. 15(3) 120-124 Waguespack, R. W. & Bolt, D. M. (2007) Esophageal Strictures and Diverticula, Compendium: Equine Edition, July/August, 4: 194-207.

Stick, J. A. (2012). In: Equine Surgery-E-Book 4th ed Auer, J. A., & Stick, J. A. Elsevier Health Sciences. 367-387 Stick J. A., Derksen F. J. & Scott, E. A. (1981) Equine cervical esophagostomy: complications associated with duration and location of feeding tubes. American Journal of Veterinary Research. May; 42(5):727-732.

Whitfield‐Cargile, C. M., Rakestraw, P. C. & Hardy, J. (2013).

Treatment of cervical oesophageal rupture in horses. Equine Veterinary Education, 25(9), 456-460.

SUPPORT ON EQUINE MATTERS: HOW TO CONTACT YOUR NZEVA EXECUTIVE As part of the NZEVA executive’s role, we are asked to consider, comment, and advise on a range of topics affecting equine practitioners including policy review, current equine welfare concerns, member resources, and current issues being experienced by practitioners. Where appropriate we consult NZEVA/NZVA members with expertise in the relevant area, usually via our sub-committees. Although many of these matters are brought to us by scheduled review within our sub-committees, or delegated to us by the NZVA, we also receive correspondences from equine practitioners directly throughout the year. If there are topics affecting you in equine practice that you would like to raise, the following are the best ways to get in contact:

 Email nzevapresident@gmail.com or nzevasecretary@gmail. com. Currently these are attended to by President Brendon Bell and Secretary Katie Kindleysides.  Contact any member of the executive in person: the current members are listed on our NZVA SIB page (https://www.nzva. org.nz/branches/equine/) and at the front of each EVP issue.

You can also contact us to express an interest in being involved with the NZEVA executive; we require new members annually as we rotate through three-year cycles. Monthly meetings are held over ZOOM in the evening with the AGM being held in person at conference each year. We also have regular correspondence, mostly via email, between meetings.

If you would like to be more involved in equine collegial discussion on mostly clinical cases, Rabecca Mackenzie has set-up the ‘New Zealand Veterinary Practitioner Group’ on Facebook to support EVP and give NZ vets working with horses a place to get feedback on a variety of unusual and routine cases and procedures. If you would like to join, please contact Rabecca via Facebook or email myself. Existing members of the group can also invite their friends to the group; verification they are a vet working in New Zealand will be made before new members can join.

Katie Kindleysides NZEVA Secretary nzevasecretary@gmail.com

Eq Vet Pract March 2022; 47(1) 25

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THERIOGENOLOGY CLINICAL POSER Babiche Heil | babiche@matavet.co.nz See page 67 for answers While examining the fetal membranes of a mare after a normal foaling you notice the structures pointed out by the white arrows on the chorioallantois in figures A and B. The structures are ~2 cm long.

(i). What are these structures?

(ii). What is their significance?

DRUG POSER See how you respond to our clinical poser involving this formulation of an antimicrobial compound. https://www.sciencebuddies.org/

DEPOT (LONG-ACTING) PENICILLIN-G Stephanie Brooks equine@matamatavets.co.nz Regarding the long-acting penicillin-G formulations for systemic use in horses: •

What are the usual constituents of depot-penicillin-G combination drugs?

•

What class of drug is penicillin-G?

•

What is the main spectrum of activity of this combination of penicillins?

•

What is the manufacturer-recommended dose regimen?

•

What are the manufacturer-recommended indications for its use?

•

Is long-acting penicillin combination drug an effective substitute for procaine penicillin-G use in horses?

•

What are the most frequently encounted adverse reactions?

See page 66 for considered responses

Eq Vet Pract March 2022; 47(1) 27

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THE CLINICAL COMPANION OF DONKEY DENTISTRY Register with the Donkey Sanctuary

HERE

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.

28 Eq Vet Pract March 2022; 47(1)

for your free PDF copy of:

Lilly, G. & Evans, L. (Eds.).

The Clinical Companion of Donkey Dentistry.

Sidmouth, Devon. EX10 0NU. UK The Donkey Sanctuary.

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Available via:

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VETLOGIC PUZZLE - EVP MARCH 2022

4. The album with the least tracks was either by Hamilton Haemostats or was titled Anastomuzacs.

Using these clues and the fillable grids, can you work out which band produced which album and how many tracks each recorded?

TRACKS

3. Rocking Rectal had one less track than Bloody Nuisance.

Anastomuzacs

Haemorrhaging

Bloody Nuisance

Canterbury Clamps

ALBUM TITLE

10 11 12 13 Bloody Nuisance ALBUM TITLE

2. Regarding the albums with the least and the most tracks, one was by Southland Swabs and the other was titled Rocking Rectal.

Hamilton Haemostats

1. Rangitikei Rongeurs called their album Haemorrhaging.

Southland Swabs

Rangitikei Rongeurs

BAND

Rocking Rectal

Four of our colleagues’ practices that have fledgling pop music bands have released their first vinyl LP albums with different titles and different number of tracks:

Rocking Rectal Haemorrhaging

See page 66 for answers

Anastomuzacs

BAND

ALBUM TITLE

TRACKS

Rangitikei Rongeurs Southland Swabs Hamilton Haemostats Canterbury Clamps

CALL FOR ABSTRACTS NZVA Conference, June 20-23 2022 Claudelands Event Centre, Hamilton SUBMIT YOUR NZEVA PRACTITIONER PAPER AND RESEARCH PAPER APPLICATIONS NOW The page for abstract submission is at: https://www.nzva.org.nz/2022-conference/abstract-submissions/ Or you can go direct to the forms at: Research Paper Form | Practitioner Paper Form Should your submitted application be successful you will receive complimentary conference registration for the day you are speaking. Please submit your on-line form by Monday 28th March 2022 Eq Vet Pract March 2022; 47(1) 29

Carl Ekstrand C et al. The disposition of trimethoprim and sulfadiazine in neonatal foals after intravenous administration. Vet Med Sci 2022. Online ahead of print. https://pubmed.ncbi.nlm.nih.gov/35152563/ Five doses of trimethoprim (2.5 mg/kg) plus sulfadiazine (12.5 mg/kg) were administered IV BID to eight three-day-old foals and blood levels were monitored. It was concluded that for trimethoprim, the plasma exposure was insufficient in some foals to successfully treat bacterial infections such as E. coli with an MIC-value of 0.5 μg/ml using the studied dosing regimen.

Steuer AE et al. Parasite dynamics in untreated horses through one calendar year. Parasit Vectors.

2022;15(1):50. https://parasitesandvectors.biomedcentral.com/articles/10.1186/s13071-022-05168-z A herd of 18 mares, one stallion, and 14 foals born in 2018 were followed throughout 2018 the year in Kentucky, USA. Sera and feces were collected biweekly from all horses, and worm burdens enumerated in 13 foals at necropsy. An S. vulgaris ELISA antibody test was run on all serum samples. Fecal egg counts were determined for all horses, and coproculture and qPCR assay were employed to test for the presence of S. vulgaris in the mature horses. There was a general lack of seasonality in strongylid egg shedding throughout the year among the mature horses, and no post-parturient rise was demonstrated. Shedding of S. vulgaris eggs displayed a higher abundance during the spring, but findings were variable and not statistically significant. Anti-S. vulgaris antibody concentrations did not display significant fluctuations in the mature horses, but evidence of passive transfer of antibodies to the foals was demonstrated, and foals assumed their own production of antibodies starting at approximately 20 weeks of age. Overall, colts shed higher numbers of strongylid, ascarid, and S. westeri eggs than fillies. Thus, it appears that there was a lack of seasonality in strongylid egg shedding for the study population, which is in stark contrast to previous studies conducted elsewhere. This strongly suggests that more studies should be done investigating these patterns under different climatic conditions.

Gold JR et al. Pharmacokinetics and pharmacodynamics of repeat dosing of gabapentin in adult horses. J Vet Intern Med. 2022: 16386. Online ahead of print. https://onlinelibrary.wiley.com/doi/10.1111/jvim.16386 Six healthy adult mares received 40 and 120 mg/kg of gabapentin PO, BID for 14 days. Horses were examined and scored for ataxia and sedation daily. Serum biochemistry variables were analyzed before treatment and days 7 and 14 after gabapentin administration. Plasma disposition of gabapentin was evaluated after the first and last drug administration. No changes occurred in physiologic or biochemical variables. Median (range) maximal plasma gabapentin concentrations (μg/mL) after the last dose (day 15) were 7.6 (6.2-11) and 22 (14-33) for 40 mg/kg and 120 mg/kg doses respectively. Maximal concentration of gabapentin was reached within 1 hour after drug administration. Repeated administration of gabapentin resulted in a median (range) area under the curve (AUC-12 hours ) last/first dose ratio of 1.5 (1.00-2.63) and 2.92 (1.4-3.8) for the 40 and 120 mg/kg regimens, respectively. These results suggest that horses tolerate gabapentin up to 120 mg/kg PO, BID for 14 days.

NOTE: as suggested by authors, any nociceptive and/or anticonvulsant effects of the dosage regimens used needs to be determined.

30 Eq Vet Pract March 2022; 47(1)

CASE REPORT GUTTURAL POUCH MYCOSIS: AN INCIDENTAL FINDING? Gareth L. Fitch leefitch@cityu.edu.hk

SIGNALMENT A 15-year-old TB gelding presented for investigation of a respiratory noise and weight loss. The horse had been purchased 8 months previously and a pre-purchase examination was performed prior to purchase. The horse was then rested for one month prior to beginning exercise. The horse was reported to have a good appetite, normal faeces, regular dental maintenance and was regularly de-wormed.

EXAMINATION FINDINGS On presentation, clinical parameters were all within normal limits. There was no nasal discharge or malodour of the breath. There was loss of topline musculature and body condition score was scored 4/9. Melanomas were present on the tail and around the perianal area. There were no palpable melanomas in the parotid area or visible elsewhere on the horse’s head or body.

Figure 1. Left-sided RLN. Pharyngeal tone and function appeared normal.

The horse was sedated with detomidine at 0.02 mg/kg IV and an endoscopic examination of the upper airway was performed. It was apparent that there was left-sided recurrent laryngeal neuropathy (RLN) grade 3.3 on the Havermeyer scale (Figure 1).

Pharyngeal tone and function appeared normal and there was a brisk swallowing reflex. There was no food material within the laryngeal aperture or trachea and no feed material present in the nasal passages suggestive of dysphagia. No discharge was seen exiting either guttural pouch ostium. As the horse had melanomas on the tail it was decided to examine the guttural pouches during the endoscopic examination to determine if there was any melanosis or melanomas visible in the guttural pouches or any enlargement of the retropharyngeal lymph nodes. There was a yellowish plaque, a few cm3, overlying the cranial nerve bundle at the point where it becomes visible within the caudal aspect of the left guttural pouch with some evidence of localised lymphoid swellings (Figure 2). Pigmentation was present over the surface of the left external carotid artery which was also present on the surrounding mucosa (Figure 3). No fungal-type plaque was present in the right guttural pouch, but pigmentation was also present.

Figure 2. Infiltration of a mycotic plaque around the base of the cranial nerve bundle as it enters the guttural pouch in the medial compartment of the left guttural pouch.

Localised swellings are present that likely represent reactive lymphoid tissue.

Eq Vet Pract March 2022; 47(1) 31

The laser was applied on a low power setting (5W) over the surface of the plaque, but due to its location over the cranial nerve bundle this was not a prolonged application to avoid any thermal neural damage. A portion of the left vocal cord was also removed whilst the horse was under sedation to address the respiratory noise that was occurring at exercise.

Figure 3. Pigmentation on the surface of the External carotid artery and surrounding mucosal surface indicative of melanosis.

A rectal examination was performed to determine if there was any extension of the melanomas deeper to the perineum, but this did not appear to be the case. An ultrasound examination of the abdomen including the spleen was performed and no abnormalities were detected.

Topical application of an antifungal agent: The endoscope was then passed through the fistula to access the fungal plaque and partial removal was achieved using endoscopic biopsy forceps via the instrument channel in combination with saline flushing. Following this, 2% miconazole gel (Decozol Oral Gel®, AFT Pharmaceuticals) was applied to the surface of the plaque using a 5ml Luer lock syringe and attached 14-gauge 1 inch needle inserted into plastic tubing which was passed via the injection port of the endoscope (Figure 5). The consistency of the gel allowed application via the tubing, as well as adherence and retention on the surface of the plaque. The fungal plaque was not submitted for culture as it was considered unlikely to alter the treatment decision due to the time taken to identify the fungal species and the limited choice of appropriate antifungal medications in New Zealand.

TREATMENT Following discussion with the owner it was decided to treat the fungal infection with a combined surgical and medical approach. A standing laser surgery to create a salpingopharyngeal fistula was planned two days following the examination so that the owner, who was also a veterinarian, could be present for the procedure.

Creation of a salpingopharyngeal fistula and Laser cordectomy: The horse was positioned in standing stocks and sedated with detomidine hydrochloride IV and given 1g of phenylbutazone IV. Lidocaine hydrochloride 2% was sprayed over the walls of the nasopharynx and nasal passages. A salpingopharyngeal fistula was created into the left guttural pouch from the pharynx using a 980nm diode laser (Velas, Giga Laser, Wuhan) using a 400μm diameter fibre at 18W in continuous mode as described by Watkins and Parente 2018 (Figure 4).

Figure 4. Salpingopharyngeal fistula created at the nasopharyngeal recess

32 Eq Vet Pract March 2022; 47(1)

Figure 5. Application of miconazole gel to plaque using plastic tubing passed via the instrument channel of the endoscope.

Post-operative treatment and management: The horse was maintained on trimethoprim/sulphonamide antibiotic at 15mg/kg and phenylbutazone 1g, both given PO, BID for 5 days. Physical removal, saline flushing and treatment of the plaque was repeated daily for 7 days, then every other day for 7 days and then on 3 consecutive days prior to discharge. Eight days following surgery, there was a marked reduction in the size of the plaque, but the material was still adherent to the underlying mucosal tissue and could not be easily removed using the biopsy forceps and with flushing (Figure 6). At eighteen days post-operatively the plaque had regressed further and was easier to remove with the biopsy forceps and saline flush (Figure 7).

Twenty days following surgery and treatment only a thin layer of plaque remained (Figure 8), and the horse was discharged from the hospital with instructions to return within 2 weeks for a recheck endoscopy.

Figure 6. Marked reduction in the size of the plaque 8 days post-operatively – compare with Figure 2.

Figure 7. The appearance of the plaque following 18 days post-operatively.

Figure 8. The appearance of the plaque 20 days post-operatively and prior to be discharged from the hospital. Lesion with miconazole gel applied (right).

Follow-up examination: Eight days following discharge the horse returned for a follow-up endoscopic examination the guttural pouch was reexamined and there was just a small plaque remaining which was easily removed with an endoscopic biopsy forceps leaving a nodular area covered with inflamed mucosa (Figure 9).

The horse was discharged with no arrangement for follow-up examinations unless there were signs of any problems. Eight months following discharge it was reported that his breathing was improved, but that he still made some respiratory noise at faster speeds. His body condition score was 5/9 with recovery of top line musculature. An occasional cough at the start of exercise was reported.

Figure 9. Appearance of the plaque at the final examination (left), and appearance after final removal of the plaque (right).

Adjacent localised swellings interpreted as lymphoid tissue appear smaller.

Eq Vet Pract March 2022; 47(1) 33

DISCUSSION Guttural pouch mycosis (GPM) is not considered a common condition in horses but in certain regions is sufficiently common, as is the case here, to warrant investigation where persistent nasal discharge is present. Mycosis can occur in other locations of the respiratory tract such as the sinuses (Hunter and Nation (2011). The infection is usually unilateral but can be bilateral (Lepage and Piccot-Crezollet (2005). In bilateral cases the infection has transferred from one pouch to the other via erosion and creation of a fistula between the two pouches (Dobesova et al. 2012). It generally affects adults, but the condition has been reported in a 6-month-old filly (Millar, 2006) and two foals (Chidlow and Slovis 2017).

Nasal discharge is a common clinical sign, but not consistently present (Cook et al., 1968; Dobesova et al., 2012, Watkins and Parente, 2018). In a description of 28 cases that were referred for investigation of epistaxis or dysphagia, >60% presented with unilateral or bilateral nasal discharge with or without epistaxis (Dobesova et. al, 2012). It may be expected that the incidence of nasal discharge would be higher, but where epistaxis is present it may not be noticeable or have gone unnoticed. Of those 28 cases, five presented with nasal discharge as the only clinical sign and of the 13 cases that presented with dysphagia only 6 had nasal discharge. In this case there was no nasal discharge and also no signs of pharyngeal disfunction despite the plaque being relatively large and centered over the cranial nerve bundle that would include CNs IX, X, XI and XII. A diagnosis of mycosis was made based on appearance alone. It was regarded as highly likely to be of fungal origin and although no mycological examination was performed a decision was made to treat it as a local mycotic infection. Where mycological analysis is performed Aspergillus species are most commonly identified (Cook et al., 1968; Rawlinson and Jones, 1978; Gatineau and Ludwig, 2002; Ludwig, A., et al., 2005; Dobesova et al., 2012; Ludwig, A., et al., 2005). Of the cases described by Dobesova, mycological examination was performed in only 7 of the 28 cases and in 6 of the 7 cases Apergillus species were identified. Other species that that have been identified include Fusarium, Trichosporon, Acremonium Rhodotorula (Dobesova 2012) and Emericella nidulans (Cabanes et al., 2002; Kosuge, J., et al., 2000). Examination of a biopsy is more productive in identifying fungal infection than culture (Freeman and Hardy 2012, Dobesova 2012). The options for medical treatment of fungal infections are limited in New Zealand. In this case, there was concern that the location of the infection could result in dysphagia and so treatment was initiated as soon as possible.

This case presented for investigation of respiratory noise and was diagnosed with left recurrent laryngeal neuropathy (RLN).

Laryngeal hemiplegia in cases of guttural pouch mycosis has been reported (Dobesova 2012; Lepage et al. (2021). In a description of neurologic dysfunction caused by guttural pouch disease (Borges and Wantanabe 2011) it was stated that vagal lesions at the guttural pouch site could affect all branches except the auricular and that dysphagia and inspiratory

34 Eq Vet Pract March 2022; 47(1)

dyspnea (due to laryngeal paralysis or displacement of the soft palate) are the clinical signs that are observed with vagus lesions at the guttural pouch site. Of 28 cases presenting with GPM (Dobesova 2021), 10 also had RLN, two right-sided and 8 left-sided, and in all cases the hemiplegia corresponded to the side of the mycotic lesion. Interestingly, but perhaps not surprisingly, all the cases with RLN presented with dysphagia with or without epistaxis. The recurrent laryngeal nerve arises from the parent vagal nerve in the cranial thorax to return up the neck to the larynx without passing via the caudo-dorsal wall of the guttural pouch. Thus, if the plaque caused the RLN it would need to have markedly involved the left vagal nerve, that may be considered unlikely in the absence of other signs of vagal neuropathy, namely dysphagia. Although the RLN was left-sided in this case, as was the mycotic-like plaque, it still is very likely that it was an incidental finding and unrelated to the infection as there were no other signs of vagal neuropathy. A pre-purchase examination was performed prior to purchase, although endoscopy was not part of that procedure, no respiratory noise was identified at this time or immediately afterwards.

If left untreated, guttural pouch mycosis can result in a fatal haemorrhage where the infection is situated over the internal or external carotid arteries or branches thereof (Baptiste 2004; Delfs, K. C., et al. 2009; Archer 2012) and can cause irreversible damage to cranial nerves V, VII, IX, X, XI, or the cranial sympathetic trunk (Le Page et al., 2004). Dysphagia can result when there is localization over the nerve bundle of CN IX, X, XII as it passes through the guttural pouch. The complexity and fragility of the swallowing reflex was demonstrated in a case where the fungal infection was situated over the pharyngeal nerve only, causing only a unilateral pharyngeal dysfunction that was sufficient to cause dysphagia (Eichenttopf et al., 2016). Aggressive spread of the infection to involve adjacent structures can even cause pharyngeal fistula by eroding the dividing wall between both pouches (Dobesova 2012), middle ear infection, osteitis of underlying temporal bone, atlanto-occipital infection (Dixon and Rowlands, 1981; Ernst 2006), temporohyoid arthropathy (Walmsley, 1988), Horner syndrome and atrophy of the tongue (Ernst 2006; Cook et al., 1986; Survival rates where dysphagia is a presenting are poor and persistent dysphagia is a common reason for euthanasia (Lepage,. and PiccotCrezollet, 2005; Archer et al. 2012; Dobesova 2012).

Medical treatment alone generally gives unsatisfactory and doubtful results (Speirs et al., 1995). It has been suggested that horses can recover completely after surgical treatment without any medical therapy (Lepage et al., 2004; Leveille et al., 2000), but there are descriptions of cases where surgical treatment alone has not resulted in acceptable syndrome resolution and resulted in euthanasia or death (Ernst 2006; Eichentopf et al., 2016; Archer et al., 2012). Successful treatment of dysphagic horses with a combination of surgical and medical treatment is possible (Whitehead et al., 2018; pers. obs.), but the caveat is that treatment is often prolonged, intensive, and expensive and has a poor prognosis. Taking

this into account, treatment was initiated promptly in this case.

Successful treatment of guttural pouch mycosis in 7 horses by creation of a salpingopharyngeal fistula using a diode laser has been described (Watkins and Parente, 2018). Cited advantages of this procedure were that it could minimise cost of treatment, be performed on an outpatient basis and provide better exposure of the infected area with few complications.

That said, in this series of 7 horses, both medical and surgical treatment was carried out in some, and therefore it cannot be concluded that the surgical procedure alone would be successful. Resolution of the fungal plaques was reported to be between one to 6 months. In this case, a combination of surgical and medical treatment was chosen to resolve the infection as efficiently as possible and prior to development of any haemorrhage or cranial nerve dysfunction, especially dysphagia. In a description by Cousty et al., of 24 horses treated with ipsilateral ligation of the common carotid in combination with medical treatment for epistaxis secondary to guttural pouch mycosis, it was concluded that removal of the plaque and topical treatment of the underlying lesion appeared to speed up resolution of the mycotic lesions; in this case series the number of treatments ranged from 2-14.

Although oral preparations of antifungals are available, topical application of an anti-fungal was chosen in this case as it was significantly cheaper compared to oral therapy. The preparation chosen is used for treatment of oral candidiasis in people, and its consistency allowed administration via tubing passed down the channel of the scope, although this required the use of a Luer lock syringe due to the pressure required. The gel adhered to the lesion, and with body heat it created a film that remained on the plaque. The entire 20day treatment only required a single 40g tube of Decozol Oral Gel®. Resolution of the fungal plaque was effectively complete at discharge after 20 days of treatment and the plaque was substantially reduced after only 8 days of treatment. Although spontaneous resolutions have been reported (Freeman and Hardy 2012); in cases where arterial occlusion has not been performed and where a salpingopharyngeal fistula has been created, application of an appropriate antifungal medication is relatively straight forward to perform and may hasten the resolution of the infection. It does require hospitalisation of the horse and the associated costs, but does enable confirmation that the infection has resolved. As previously stated, in this case there was concern that inflammation of the underlying nerves may result in dysphagia and therefore, the most rapid resolution was critical.

Fortunately, in this case the mycotic plaque was found prior to any signs of dysphagia had occurred but given the lack of any external clinical signs it would have been easy to miss, as a cause of the respiratory noise had been identified. In cases where persistent nasal discharge is present, endoscopy of the guttural pouches is warranted. A combination of surgical and medical treatment allowed rapid resolution of the plaque and no progression of clinical signs.

ACKNOWLEDGEMENTS Gracious thanks to the owner of the horse in this case Freja Hudspith BVSc, and the staff at Canterbury Equine Clinic, most particularly Danielle Guiver and Hayley Jackson for input to the success of this case, and to Maree Robertson for assistance with sourcing information for the manuscript.

References Archer, R. M., et al. (2012). Guttural pouch mycosis in six horses in New Zealand. N Z Vet J 60(3): 203-209.

Baptiste, K. E. (2004). The mystery of guttural pouch mycosis: the paradox of advancing knowledge of a rare disease. Vet J 168(1): 1-2.

Borges, A. S., Marcos J. W. (2011), Guttural Pouch Diseases Causing Neurologic Dysfunction in the Horse. Vet Clin Nh Amer: Eq Pract 27(3): 545-572.

Cabanes, F. J., et al. (2002). [Guttural pouch mycosis by Emericella nidulans in a horse]. Rev Iberoam Micol 19(4): 208-211.

Chidlow, H. B., & Slovis, N. M. (2017). Guttural pouch mycosis in two foals. Eq Vet Edu 29(4), 213–218.

Cousty, M., et al. (2016). Ligation of the ipsilateral common carotid artery and topical treatment for the prevention of epistaxis from guttural pouch mycosis in horses. Vet Rec 178(2), 44-44.

Delfs, K. C., et al. (2009). Treatment of acute epistaxis secondary to guttural pouch mycosis with transarterial nitinol vascular occlusion plugs in three equids. J Am Vet Med Assoc 235(2): 189-193.

Dobesova, O., et al. (2012). Guttural pouch mycosis in horses: a retrospective study of 28 cases. Vet Rec 171(22): 561.

Eichentopf, A., et al. (2013). Dysphagia caused by focal guttural pouch mycosis: mononeuropathy of the pharyngeal ramus of the vagal nerve in a 20-year-old pony mare. Ir Vet J 66(1): 13.

Ernst, N. S., et al. (2006). Progression of mycosis of the auditory tube diverticulum (guttural pouch) after arterial occlusion in a horse with contralateral temporohyoid osteoarthropathy. J Am Vet Med Assoc 229(12): 1945-1948.

David E. Freeman, Joanne Hardy, (2012). Guttural Pouch, cg 46 in Equine Surgery, 4th ed. Eds: Jörg A. Auer, John A. Stick.

W.B. Saunders: 623-642, Hunter, B. and P. N. Nation (2011). Mycotic encephalitis, sinus osteomyelitis, and guttural pouch mycosis in a 3-year-old Arabian colt. Can Vet J 52(12): 1339-1341.

Kosuge, J., et al. (2000). [Detection of Emericella nidulans from bedding materials in horse breeding environment and its significance as a causative agent of guttural pouch mycosis in horses]. Nihon Ishinkin Gakkai Zasshi 41(4): 251-256.

Lepage, O. M., et al. (2021). The Effect of Topical Oxygen

Eq Vet Pract March 2022; 47(1) 35

Therapy in Horses Affected with Mycosis of the Guttural Pouch: An Experimental Pilot Study and a Case Series.

Animals (Basel) 11(11): 3329.

Ludwig, A., et al. (2005). Fungal isolation and identification in 21 cases of guttural pouch mycosis in horses (1998-2002).

Vet J 169(3): 457-461.

Lepage, O. M. and C. Piccot-Crezollet (2005). Transarterial coil embolisation in 31 horses (1999-2002) with guttural pouch mycosis: a 2-year follow-up. Equine Vet J 37(5): 430-434.

Millar, H. (2006). Guttural pouch mycosis in a 6-month-old filly.

Can Vet J 47(3): 259-261.

Leveille, R., et al. (2000). Transarterial coil embolization of the internal and external carotid and maxillary arteries for prevention of hemorrhage from guttural pouch mycosis in horses. Vet Surg 29(5): 389-397.

Watkins, A. R. and E. J. Parente (2018). Salpingopharyngeal fistula as a treatment for guttural pouch mycosis in seven horses. Equine Vet J 50(6): 781-786.

Whitehead, A. E., et al. (2018). Reversible dysphagia secondary to guttural pouch mycosis in a gelding treated medically with voriconazole and surgically with carotid occlusion and esophagostomy. Can Vet J 59(2): 165-170.

EXAMINATION OF HORSES | BLUE BOOK The VPIS have just re written and released the 2021 5th Edition of Examination of Horses, also known as the Equine PPE Blue Book and it is available on the following web links: VPIS: https://www.vpis.org.nz/equine-ppe NZVA: https://www.nzva.org.nz/resource/equine/ PDF: HERE

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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

Massey Equine Veterinary Clinic

NZERF - NZ Equine Research Foundation

ARVS - Association of Racecourse Veterinary Surgeons

NZEVA - New Zealand Equine Veterinary Association

BAEDT - British Association of Equine Dental Technicians

NZVA - NZ Veterinary Association

BHS - The British Horse Society

BEVA - British Equine Veterinary Association https://equinesurveillance.org/ iccview/

https://www.nzva.org.nz/events/ event_list.asp SPCA – Society for the Prevention of Cruelty to Animals-NZ Thoroughbred RACEHORSE OWNERS Federation

NZTR - NZ Thoroughbred Racing ESNZ - Equestrian Sports NZ

EVA - Equine Veterinarians Australia

EVJ - Equine Veterinary Journal

RCVS - Royal College of Veterinary Surgeons SAEVA - South African Equine Veterinary Association SIVE - Societa Italiana Veterinari per Equini

EVJ - Equine Veterinary Journal The Donkey Sanctuary Harness Racing NZ

https://www.vetpd.com/

HBLB - Racehorse Health

Eq Vet Pract March 2022; 47(1) 37

RECENT VPIS INSURANCE CASES Paul Frazer

p.a.fraser80@gmail.com

At the Veterinary Professional Insurance Society (VPIS) we regularly deal with equine insurance claims that arise when our members have, or are alleged to have, made a mistake. There are always lessons to be learnt from these situations, and we thought it would be beneficial for all equine veterinarians to have access to the knowledge gained from others’ misfortune. With this in mind, VPIS will regularly update equine veterinarians with cases dealt with, and the lessons learnt.

CASE 1: VACCINATION MIX-UP PRE-EXPORT Three horses required vaccination for Strangles and Influenza prior to being exported to Singapore to comply with Singaporean import requirements. The timing was such that it was over the Christmas period and some staff were on holiday. The prescribed vaccination dates were entered into the practice computer system.

The flight schedule changed, meaning the vaccinations would need to occur sooner than scheduled. The practice was notified of the change; however, this information was not passed on to the veterinarian handling the case. As a result, the horses were vaccinated on incorrect dates and had to miss their scheduled flights and be retained in New Zealand until another flight was scheduled. Costs were incurred for this delay.

Our insured was liable and VPIS compensated the shipping company for the carry over costs.

• Lessons learnt: There were systems errors on the part of both the shipping agents and our insured.

The vet practice has changed their systems to ensure vaccinations on specified dates. The shipping company also recognised a weakness in their system and designed a new template for agents to use detailed exact export dates.

CASE 2: CASTRATION DEATH SECONDARY TO EVISCERATION A seven-month-old pony colt was castrated under general anaesthetic. The risks of complications, including evisceration, were clearly explained by our insured before beginning the procedure. The surgery appeared to go well, but bowel came out the castration wound immediately after.

Our vet contacted a referral facility for advice and attempted to suture the wound. This was unsuccessful so the area was protected with a bandage and the horse was sent on for surgery. Unfortunately, the pony failed to recover. The specialised treatment came to around $4,000 and there was concern about who should pay for this.

Our insured vet did everything right in presenting pre-surgical risk to the client and in carrying out the castration. It is well recognised that around 0.4% of castrations may eviscerate.

There was no breach of professional duty on the part of our vet. The practice excess with VPIS was $2,000 plus GST. In this case, it was felt it would be better to direct this money to the client to help pay the bill. This resulted in a successful resolution with all parties satisfied.

• Lessons learnt: Good proactive communication regarding possible complications is important and certainly shielded our insured from any possible blame in this case. While there was no breach of professional duty here, a common sense and practical approach to handling the case resulted in satisfaction for all parties.

38 Eq Vet Pract March 2022; 47(1)

CASE 3: DEATH OF A HORSE SECONDARY TO THE USE OF MATRIX A trainer wanted a liquid oral drench to stomach tube four horses. No registered equine liquid drench is available, so Matrix (abamectin/levamisole/oxfendazole) was prescribed.

It is important to note that Matrix is available in two strengths: Matrix mini dose for sheep and Matrix C, which is four times the strength. The horses’ owner was given Matrix C. The vet assumed that the mini dose had been dispensed and gave instructions for a dose rate based on that product when the dose recommended was in fact four times that. One of the horses developed acute nervous signs, collapsed, and eventually died.

By failing to establish the strength of the drench dispensed, our insured had breached his professional duty and was liable.

After negotiation a realistic value of the horse was obtained, and the owner was compensated for the loss.

• Lessons learnt: Matrix contains levamisole which has a very narrow margin of safety in a horse. Toxicity is, effectively, organophosphate poisoning. Take extreme care when prescribing “off label” products, especially if they contain levamisole.

CASE 5: POSSIBLE SE TOXICITY A horse underwent a veterinary examination for poor impulsion and stiffness. Routine bloods were taken, and a low blood selenium was noted. Sup‐ plementation was advised. A communication mixup ensued, and the horse was double dosed with selenium over a period of two weeks at which time the error was recognised. A blood re-test at this time showed no toxicity. The horse subsequently went to a referral clinic for work up for another issue and the selenium was rechecked. The result was again normal.

Six months later, the practice was contacted by the owner, who believed the horse’s performance had been compromised by a condition she perceived as being linked to selenium toxicity. An expert opinion was sought, and the horse was re-examined. No clinical signs relating to selenium toxicity could be found.

There was no breach of professional duty, this was communicated to the owner, and liability was denied.

• Lessons learnt: Take care of dose rates. Beware clients with some self-gained veterinary knowledge!

Keep good records when communicating with clients, particularly with someone who appears potentially ‘problematic’.

CASE 6: DEATH OF A HORSE WITH A NERVOUS DISEASE A pony in an isolated region developed acute nervous signs including stiffness and ataxia. The only vet on duty was a small animal vet covering all calls. The vet contacted a more experienced colleague before and after seeing the pony. The vet made a tentative diagnosis of ryegrass staggers but, for safety’s sake, sent the pony on to a referral facility.

Upon arrival, with the aid of blood tests, the pony was diagnosed with the unusual condition, hyperammonaemia.

The syndrome was severe enough that the pony did not survive.

CASE 4: DEATH OF A HORSE AFTER TUBING A valuable sport horse was treated for colic. As part of that treatment, it was stomach tubed with liquid paraffin. There was an issue with the tubing process. The horse developed respiratory signs and was sent to a referral clinic. A transtracheal wash revealed paraffin in the lungs and aspiration pneumonia.

After an initial response, the horse deteriorated and was euthanised. The condition was attributable to a failure on the part of our insured vet and a settlement was negotiated.

• Lessons learnt: With the advent of paste wormers, stomach tubing is a procedure that is performed less often than it used to be. Technique is important, and care needs to be taken to establish the positioning of the stomach tube with absolute certainty.

The owner felt the vet attending lacked experience and made the wrong diagnosis. They sought the value of the pony and treatment expenses.

Our insured did absolutely nothing wrong. An experienced colleague was consulted throughout, and the original diagnosis was rational and appropriate, as was the decision pathway. After consultation with the insured practice, we took a pragmatic approach to this case. The practice had an excess of $2,000 for any claim and while we could have defended it, this would have cost more than the excess and created ill will with the client and distress for the vet. The referral treatment expenses amounted to $1,500 and we felt that the practice paying this bill directly was better than spending the money on insurance excesses.

Eq Vet Pract March 2022; 47(1) 39

This pathway was taken after carefully explaining to the client that the vet had done nothing wrong but there are no winners in a situation like this and the practice felt money was better spent helping the client through their unfortunate circumstances rather than on defending a claim. The result was that all parties were satisfied.

The trainer of the horse was subject to a regulatory hearing, found guilty of presenting a horse for racing that contained a prohibited substance and a fine was imposed. The drug had been used on veterinary advice; therefore, our insured vet was liable and VPIS reimbursed the trainer for the fine that had been paid.

• Lessons learnt: Good communication, decision making, and support go a long way to mitigating risk, even when experience is less than optimal. Professional indemnity insurance is about resolving a claim and not necessarily about proving who is right or wrong, this resolution may not always appear “fair”.

• Lessons learnt: The NZEVA prohibited substance recommended withholding times is not a comprehensive list. If a drug does not appear on it, especially if it is a drug not commonly used, make enquiries, and assume it has a withholding time until proven otherwise.

COMMENTS ON THESE CASES There is a common denominator in most insurance claims.

Very few arise from true clinical mistakes, most revolve around poor communication. This may be internal through poor implementation of practice systems, or it may be through ineffective interaction with clients. Poor communication, record keeping, and internal processes also feature in Veterinary Council complaints. There is no doubt that attention to this important part of veterinary practice will reduce claims.

The cases described here also show that timely and clear communication can have a positive influence by minimising exposure in the event of client conflict.

CASE 7: DRUG RACE WITHHOLDING TIME MISTAKE. A vet had prescribed the antihistamine cetirizine for a respiratory condition. The NZEVA guide to withholding times was checked and the drug was not listed. The vet incorrectly assumed that this meant there was no withholding time and the standard “one clear day” applied. However, the list put out by the NZEVA is a not a comprehensive list of all drugs used in horses, it is a guide that includes only drugs commonly used.

It is important to remember that, as insurers, we are only involved when things go wrong, and it is far more likely that potential client conflicts will have already been resolved as result of good communication. As a profession trusted by the public, veterinarians are highly regarded and much of this is because of our communication skill; we do it well so let us continue to do just that.

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EVP INTERVIEW WITH COLLEAGUE CHRIS RILEY Professor of Equine Clinical Studies, Massey University C.B.Riley@massey.ac.nz

What is your practice area, and how many years have you been doing this?

My current practice is academic, focused mostly on research with some teaching and clinical service in equine surgery, and promotion of external stakeholder engagement for the University. Almost 34 years since graduating (hard for me to believe!) work has included stints in private practice in Australia, USA, and Canada.

Before coming to New Zealand, I spent about 70% of my time in North America doing referral work and about 30% doing research and non-clinical teaching.

Where did you obtain your veterinary degree, and did you take on any post-graduate studies?

I obtained my vet degree at the University of Melbourne, after a degree in physics while in the Royal Australian Airforce. After an internship at Murdoch University, I completed a residency in Large Animal Surgery, MSc and PhD at the University of Saskatchewan, Canada.

I qualified as a specialist in veterinary surgery the following year while working at Iowa State University.

About 10 years later I completed a business qualification in Innovation Management at the Melbourne Business School.

Why did you choose this area of practice?

During the last year of my vet degree, and during my internship I became more and more interested in the challenges of doing surgery on these large and complex animals. I enjoyed the mixture of intellectual challenge and technical requirements with the very real physical challenges of doing large animal surgery. Thinking calmly on your feet has always appealed to me.

Any bumps and hurdles along the way to get here?

Yes. I had to work throughout my vet programme to pay my fees and living expenses. I didn’t get much sleep, but I graduated owing only $2000. Getting into the residency program in North America was extremely competitive and required adaptation to a system very different to the one I was used to. Once again, not much sleep, but I came out at the end with qualifications that have opened many interesting doorways since. About 21 years out I came close to quitting the profession as I was feeling unfulfilled professionally. This changed for the better after I accepted a position as a large animal surgeon at the Atlantic Veterinary College in Canada where I worked for 11 years.

Outline the data and knowledge sources that are most useful to staying current in your areas of practice.

Having Google and ResearchGate profiles are helpful in providing me with regular alerts about articles in my interest areas. I also review many articles for journals which requires me to keep up with new developments.

Being open to learning about veterinary practice on other species and in other fields helps me to sustain my professional creativity and curiosity.

What do you like most about your work?

Difficult to choose. I greatly enjoy teaching surgery and ensuring our students have strong foundational skills that will sustain a lifelong career. I still find it inspiring to work with our future colleagues and to see them succeed at university and after graduation. Research plays a big part in my career satisfaction, as I still enjoy the challenges of discovery and collaboration, trying to answer questions of interest to New Zealand and globally, and sharing what has been discovered with our profession and the public.

What is the most challenging part of your job?

Working in a large complex organisation with many different demands, particularly during times of rapid and far-ranging changes. Like most academics this tends to pull me in several different directions, requiring me to balance my veterinary professional roles with many others in the University.

What advice would you give to someone thinking of following your line of practice?

If creativity and curiosity are part of what drives you, an academic environment allows you to explore new ideas and collaborations, and to meet interesting people within and outside of our profession. Pursue your veterinary professional passions. Seek out those who are supportive and encouraging of your professional ambitions, and minimise the time spent with those that are negative and discouraging. Do not only think about how your career path will benefit you, but how might your skills and experience benefit those around you, whether they be colleagues, clients, or the wider community. Build positive collegial relationships, prioritising time to listen to and acknowledge people.

Eq Vet Pract March 2022; 47(1) 41

Share your best practice tip Never drop or lose a thermometer again. Take a piece of strong non-absorbable suture material and attach it with adhesive tape to the end of your thermometer. Attach the other end to a small bulldog clip. This way you can put the thermometer in the rectum and clip it to the tail hairs while finishing your exam.

Give us a Tweet on Brexit, Trump, Putin… or anyone/thing else you like.

“Those that aspire to mediocrity are rarely disappointed”.

Per ardua ad Astra: motto of the Royal Australian Air Force.

A FEW PERSONAL QUESTIONS Sporting event/concert you travel back in time for: seeing Bob Marley and the Wailers live Should our BVSc [Massey] programme include substantial species or discipline specialization, or should that be mainly left to post-graduate training periods?

I think there should be greater capacity within the BVSc programme for students to have some course electives in the earlier years of the programme, allowing them to develop a greater depth of skills/knowledge in species or disciplines of their interest. There’s been an increased breadth of skills development in accredited veterinary degrees worldwide, but this has been at the cost of depth.

Of course, there are different cost-benefit propositions for each programme option. Postgraduate training has its place, but there are relatively few equine opportunities in New Zealand, and there is limited standardisation in terms of quality of training and supervision for those that do exist.

What annoys you most about your current veterinary involvement?

I am certainly no saint, but I do try not to let myself get too worked up or negative about the challenges of our profession. I prefer to put my energies into what can be done without having unreasonable expectations about the speed with which change occurs. I guess like most veterinarians, I still don’t enjoy working for or with people that are negative, confrontational, or unreasonable, whether they be colleagues or clients.

What are your passions outside of work?

Boring I’m afraid. I do pottery and sculpture and have my own studio. I give a few classes every year and occasionally have an exhibition. I like the immersive and freeing experience of converting dirt into art or functional objects. We live close to the beach, and I enjoy heading there when I can, as well as caring for my family and small lifestyle property. I also enjoy learning about different cultures when travelling.

Last memorable meal: Canadian lobster tails last year Best-ever or best-tentative dinner party guests: Professor Mohan De Silva MS, FRCS Edin, FCSSL is a retired human surgeon and educator whom I met while working in Sri Lanka. I was impressed and very moved by his humanity and heartfelt recollections of working with the severely injured in extremely difficult circumstances during the Sri Lankan civil war. A doctor, a singer, a cricketer, and a true Renaissance man.

First-ever concert: Spandau Ballet – embarrassing?

Favourite ever album/band: Dark Side of the Moon, Pink Floyd Finish the sentence: no woman/man should ever wear… : Spandex Beer or wine/Stones or Beatles: A good south Australian Cabernet; old style of course ~ Beatles.

What was the last lie you told?

I’ll be home from work soon …

Most interesting surgery you have done: Bilateral artificial cruciate ligament insertions in a valuable New Zealand Jersey cow.

Best self-defence tip: Take a deep breath, let it out quietly and slowly, and relax your body. You will be able to move more quickly when the time comes.

Person(s) who influenced you most in your life: My grandfather – an aboriginal man, veteran, tough horseman and breaker Best life lesson/life motto: Be patient, listen and be empathetic and kind Final comments Humbled by this invitation.

42 Eq Vet Pract March 2022; 47(1)

EVP EDUCATIONAL FUND Dear Colleagues.

Did you know that you are eligible to apply for EVP funds to assist you in obtaining equine veterinary experience, training, travel, CPD etc? This is an annual sum of money is set aside each year by the NZEVA EVP Editorial Group to establish a Continuing Education (CE) fund.

These funds can be for use overseas or within Aotearoa. Possible uses of funds include attending the NZVA/NZEVA conference or short courses, spending time at specialist equine clinics and learning new skills from other (non-clinical) sources e.g., veterinary pathology laboratory.

Liquid supplement containing Glucosamine, Chondroitin & Biotin suspended in Omega Oil for bone & joint health, mobility & hoof condition in horses.

The two main purposes of this fund are:

• •

facilitating continuing education and/or specialist training for all paid up NZVA members and EVP Editorial Group members disseminating information resulting from such funding that is of benefit to New Zealand equine practitioners through publication in the Equine Veterinary Practitioner journal

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 – CoViD permitting - present a verbal report to the NZEVA EVP Editorial Group at a convenient 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 interest and value to NZ equine practitioners.

5. Applications can be made in writing to and will be assessed by two members of the EVP Editorial Group [currently JM and BH], who are NOT eligible for funding.

6. The application must include a signed statement: “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.

Applications to evp.editor@gmail.com, anytime.

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Eq Vet Pract March 2022; 47(1) 43

EquiManagement Magazine Winter 2021

Read or download a PDF of the Winter EquiManagement Magazine HERE CONTENTS INCLUDES: y Transmission of Equine Herpesvirus y Uterine Infusion of Platelet-Rich Plasma y Intestinal Microbiome y Nutrition for the Performance Horse y Tendon and Ligament Injury Treatments y Enteral Fluids for Intestinal Impaction and the Potential for Volvulus READ OR DOWNLOAD A PDF OF THE WINTER EQUIMANAGEMENT MAGAZINE HERE

Also free access to EquiManagement Updates

Research Reports Disease Du Jour podcast Business of Practice podcast

https://equimanagement.com/page/newsletter https://equimanagement.com/disease-du-jour-podcast https://equimanagement.com/the-business-of-practice-podcast

News From NEW ZEALAND EQUINE RESEARCH FOUNDATION – NZERF The NZERF Bulletin for Summer 2022, Vol 27 (1) is now available via

NZERF website at https://www.nzerf.co.nz/

NZERF are also developing brief educational videos on topics of interest.

The first of these videos, presented by Paul Fraser, is on Strangles available HERE

The second, also presented by Paul Fraser is on Laminitis available HERE

And the latest to be released is on Gastric Ulcers, presented by Ben Sykes, available HERE

Further videos are planned for release over the next few months. Secretary NZREF, PO Box 52, Palmerston North allan.fenwick@xtra.co.nz

44 Eq Vet Pract March 2022; 47(1)

EQUINE CONFERENCES, SEMINARS & WORKSHOPS FROM MARCH 2022 Image credit: ACVECC

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 https://www.ivis.org/home.asp And keep abreast of opportunities on VetPD and NZVA calendar sites Aware of an upcoming equine event? Please inform the editor evp.editor@gmail.com

    

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. Some of them even keep track of what you have watched, so you can easily and painlessly claim for CPD!

2022 MARCH

March / April:

NZVA Technical emergency large animal rescue course. ONLINE

MAY

May 9-13:

EVDS Equine Dentistry Course - Level 2 Revision/Intermediate. South Grafton, NSW, AUS. LIVE

May 22-27:

AVA Annual Conference. Gold Coast, QLD. LIVE

JUNE

June 6-11:

EVDS Equine Dentistry Course - Level 1 Essentials. South Grafton, NSW, AUS. LIVE

June 20-22:

NZVA/NZEVA Conference. Claudlands, Hamilton. LIVE

June 23:

VetPD Workshop - Foot lameness and podiatry. Waikato – venue tba. LIVE

June 23-25:

ACVIM Medicine Forum. Austin, TX. USA. LIVE & VIRTUAL

June 23-25:

ANZCVS Science Week. Gold Coast. AUS. LIVE & VIRTUAL

JULY

July-Feb 2023:

Applied Veterinary Epidemiology. Massey University. ONLINE

July 7-9:

ECVS - Annual Scientific Meeting. Porto, Portugal. ONLINE

July 20-23:

Society for Theriogenology Conference. Bellevue, WA, USA.

SEPTEMBER

Sept 7-11:

IVECCS Emergency & Critical Care Symposium. San Antonio, TX. USA

Sept 14-17:

European Veterinary Diagnostic Imaging (EVDI). Edinburgh, UK. LIVE

OCTOBER

Oct 19-22:

European College of Equine Internal Medicine. Lyon, France. LIVE

Oct 30-Nov 5:

VetPD Safari Event. Dinokeng Game Reserve, South Africa

NOVEMBER

Nov 18-22:

AAEP Annual Convention. San Antonio, TX. USA. LIVE & ONLINE

2023 Planned

NZVA Race Day Course

Planned

NZVA Equine Dentistry Course - Level 1

Eq Vet Pract March 2022; 47(1) 45

We provide emergency service 24 hours a day, 7 days a week.

We are a team of highly qualified equine veterinarians, including a registered Specialist in Equine Surgery with extensive experience.

We provide the highest quality of first opinion, emergency, and referral services for all horses and ponies, from the paddock pet to the elite athlete.

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Our routine hours of operation are from 8am to 5pm Monday to Friday, with our reception also open on Saturday from 8am to 11am.

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 an eye open for this.

Murata, D et al. Osteochondral regeneration of the femoral medial condyle by using a scaffoldfree 3D construct of synovial membrane-derived mesenchymal stem cells in horses. BMC Vet Res 2022; 18(1): 53. DOI: 10.1186/s12917-021-03126-y After culturing equine synovial membrane-derived mesenchymal stem cells (SM-MSCs) until P3, we prepared a construct (diameter, 6.3 mm; height, 5.0 mm) comprising approximately 1920 spheroids containing 3.0 x 10(4) cells each was subsequently implanted into an osteochondral defect (diameter, 6.8 mm; depth, 5.0 mm) at the right femoral medial condyle. The contralateral left femoral defect served as the control. MR imaging and macroscopic and histological characteristics were scored. Compared to the control sites, the implanted defects showed better total scores suggesting that implantation of a scaffold-free 3D-construct of SM-MSCs into an osteochondral defect could regenerate the original structure of the cartilage and subchondral bone over 6 months post-surgery in horses, indicating the potential of this technique in treating equine subchondral bone cysts.

46 Eq Vet Pract March 2022; 47(1)

CASE REPORT MEDICAL MANAGEMENT OF BILATERAL GUTTURAL POUCH TYMPANY IN A THOROUGHBRED FOAL Lucy Russell

lucy@srvs.co.nz

​ mma Gordon E E.Gordon1@massey.ac.nz

GP tympani in a TB foal

INTRODUCTION

DIAGNOSIS

Guttural pouch tympany most commonly affects foals but is occasionally seen in older horses. Entrapment of air in one, or less commonly both, guttural pouches occurs due to inability of trapped air to escape via the normal route into the pharynx via the pharyngeal opening. The exact cause is not known but theorised to be due to an anatomical or functional abnormality at the pharyngeal orifice causing a one-way valve effect (McKinnon et al, 2011). Evidence of a genetic component has been demonstrated in Arabian and Warmblood foals (Blazyczek et al, 2004; McKinnon et al, 2011).

A thoracic ultrasound examination revealed moderate numbers of scattered comet tails on the left and right cranioventral lung lobes coalescing to sheets ventrally. No free pleural fluid was seen. Upper respiratory tract endoscopy showed marked, bilaterally symmetrical dorsal pharyngeal collapse, causing intermittent, intermittent partial obstruction of the airway during inspiration (Figure 1).

CLINICAL EXAMINATION AND CASE PROGRESSION A Thoroughbred colt foal was presented for evaluation at two days of age for acute onset, bilateral, soft swelling behind the mandibular rami, accompanied by a loud respiratory noise.

Clinical examination revealed mild-moderate enlargement in the region caudal to the ramus of the mandible, in the parotid region on the left and right sides. The swellings were soft, fluctuant and non-painful. A mild-moderate inspiratory and expiratory stertorous respiratory noise was present. The swelling and noise were observed to wax and wane, being least significant when the foal was relaxed and more significant when restrained, excited and after exercise. The foal’s clinical examination was otherwise unremarkable. Given the age, onset and clinical appearance, a presumptive diagnosis was made of bilateral guttural pouch tympany (Caston et al, 2015).

It was initially elected to monitor the foal closely in the short term, owing to the fact that the swelling was soft and appeared to fluctuate during the day, suggesting that there may be some ability for trapped air to escape the guttural pouches into the pharynx. Over the following weeks the swelling and respiratory noise was observed to be gradually reducing overall, although some daily fluctuation was still seen.

At 28 days of age, the foal was presented for examination due to an acute bilateral increase in swelling in the region of the guttural pouches and increased respiratory noise. Clinical examination revealed marked inspiratory and expiratory stertorous respiratory noise at rest and marked soft, fluctuant swelling in the region of the guttural pouches on the left and right. The foal was dull, with rectal temperature of 39.8oC.

Figure 1: Endoscopic view showing partial naso-pharyngeal collapse during inspiration in top frame, and same view during expiration in bottom frame, with left guttural pouch opening visible on right of images .

No other abnormalities were seen. A venous blood sample revealed a moderate leucocytosis, with a neutrophilia, lymphocytosis and monocytosis, and elevated fibrinogen (Table 1).

Eq Vet Pract March 2022; 47(1) 47

Table 1. Haematology and biochemistry results of interest in the case Antibiotic course Day 1

Day 4

Ref. Range

WBC x109/L

16.7

10.1

6.0-11.4

Neutrophils x109/L

11.3

5.1

2.7-7.4

Lymphocytes x109/L

4.5

4.3

1.8-4.4

Monocytes x109/L

0.7

0.5

0-0.3

Fibrinogen g/L

6

5

3-5

Blood parameter

Diagnoses of bilateral guttural pouch tympany and aspiration pneumonia were made.

TREATMENT Blood results were consistent with infection/inflammation (Carrick and Begg, 2008; Walton, 2013). This supported the clinical suspicion of pneumonia, based upon ultrasonographic findings. The pneumonia was postulated to be due to dysphagia secondary to the pharyngeal dysfunction.

Treatment was commenced with ceftiofur sodium at 5 mg/kg IM, BID for five days, and gentamycin at 6.6mg/kg IV, SID for three days. A repeat blood sample showed the leucocytosis, neutrophilia, and lymphocytosis to have resolved, and the monocytosis, and elevated fibrinogen to have markedly improved [Table 1] and repeated ultrasound examination of the thorax revealed occasional, scattered, comet tails in the cranio-ventral lung lobes on the left and right. The foal’s condition remained stable during treatment. Guttural pouch distension and respiratory noise remained unchanged.

Following resolution of pneumonia, the foal was anaesthetised, and Foley catheters were placed bilaterally into the guttural pouches. An intravenous catheter was placed into the left jugular vein. The foal was sedated with xylazine (1.1mg/kg) and anaesthesia was induced with ketamine (2.5mg/kg) and diazepam (0.05mg/kg). The foal was placed on a padded mat in left lateral recumbency and a video endoscope introduced into the right nostril to allow visualisation of the left guttural pouch opening. The tip of a 24 Fr Foley catheter (Greet, 2015) was threaded onto a bent mare uterine catheter which acted as a guide (Figure 2), allowing the catheter to be introduced via the left nostril into the nasopharynx where it was manipulated through the guttural pouch opening into the pouch (Figure 3) when 10mL of saline was used to inflate the balloon on the Foley catheter before the guide was gently twisted and

removed and the Foley catheter placed under slight tension to ensure it remained lodged in place (Figure 3). The procedure was repeated on the right side. The catheter ends protruding from the nostril were secured through a tape butterfly placed around the Foley on the internal side and a second tape to disperse pressure on the external, through the lateral edge of the false nostril using non-absorbable, monofilament suture (Supramid, USP 2) (Figure 4). The procedure used for Foley catheter placement was that described by Caston et al, 2015, and Greet 2015. Recovery from anaesthesia was uneventful.

Maintenance included daily cleaning of the protruding catheter ends, suture sites and nostrils, and the catheters were flushed daily with 5mL of air to ensure patency.

The foal pulled each catheter once during the first week of treatment and these were replaced following the above protocol under GA, using a hand-held fibre-optic endoscope.

Securing of the Foley catheters was thus modified. The free ends were initially secured by taping with human strapping tape to the sides of the face (Figure 4). A button was added on the external side of the nostril to disperse pressure due to pressure necrosis at the original suture site (Figure 4). This resulted in no further damage to the nostrils, and the catheters were not pulled out after the tape was added.

CASE PROGRESSION Once the Foley catheters were placed, the guttural pouch distension reduced substantially within minutes, one side at a time, and only recurred when the foal pulled the catheters out during the first two weeks of treatment. Gradual resolution of the remaining distension occurred over the next week.

Catheters were retained in place for a period of five weeks (Greet, 2015) after which no recurrence of tympany was observed. Upper airway endoscopic examination four months after removal was normal, with normal appearance of the guttural pouch ostia (plica salpingopharyngia).

DISCUSSION This case shows that management of cases of guttural pouch tympany on farm is feasible. Use of the hand-held endoscope yielded a successful outcome and was not markedly more difficult than performing catheter placement with a video endoscope. The treatment process was easily managed on farm, reducing the stress of travel on a dyspnoeic foal, and obviating hospitalisation costs. A high level of patient care and monitoring was certainly necessary, and the on-farm presence of a qualified equine vet nurse, and 24-hour foal-watch meant the foal could be adequately managed on the farm.

Figure 2: Modified mare intra-uterine pipette inserted into end of Foley catheter to act as stylet for catheter placement. A Chambers catheter is usually used but this was not available. An A.I. pipette was thus modified by immersion in boiling water to soften the pipette end sufficiently to allow a small bend at the tip to be made using gentle pressure, that was then inserted into the lateral orifice of the catheter.

48 Eq Vet Pract March 2022; 47(1)

Figure 3: Foley catheter with attached pipette inserted into the left guttural pouch opening [top] and the Foley catheter in place following pipette withdrawal [bottom].

Gradual reduction in guttural pouch distension seen over two weeks after the initial reduction was possibly due to tissue stretching and the time taken for this to reduce, accompanied by growth of the foal.

The prognosis for unilateral or bilateral guttural pouch tympany is good using this technique. In a retrospective case series of eight foals treated via trans-nasal guttural pouch catheterisation, five foals had complete resolution of signs and went on to perform at the intended level (Caston et al, 2015). One foal was euthanased soon after admission due to severe aspiration pneumonia. Two foals died of unknown causes following catheter dislodgement, one suspected to be the result of inadvertent intracarotid administration of a sedative. Treatment in the case series (Caston et al, 2015) was completed using standing sedation, reducing the accepted risks associated with general anaesthesia, and reducing the added risks in this subset of foals associated with the presence of dyspnoea and/or inhalation pneumonia.

Presence of secondary inhalation pneumonia, likely due to dysphagia, has been implicated as an increased risk factor for poor outcome (Caston et al, 2015) in foals treated for guttural pouch tympany. For this reason, prompt and early intervention is advocated. Pneumonia was observed in this case that delayed catheterisation due to the requirement for treatment of pneumonia to first stabilise the foal’s condition.

Figure 4: Bilateral Foley catheters taped in place [top] and modification of nasal stay sutures using buttons [bottom].

Recurrence is documented (Greet, 2015) following use of this technique. Other treatment options can be considered such as surgical / laser fenestration of the median septum between the guttural pouches, or at the guttural pouch ostium to include any abnormal membrane present, or creation of a salpingopharyngeal fistula (Caston et al, 2015; Freeman, 2006; Greet, 2015). Risks of these approaches include possible requirement for general anaesthesia and inadvertent damage to the large network of neurovascular structures associated with the guttural pouches, that can result in dysphagia, aspiration pneumonia, haemorrhage, death, possible recurrence, and potential disturbance of upper airway dynamics (Freeman, 2008).

Eq Vet Pract March 2022; 47(1) 49

The benefits of trans-nasal guttural pouch catheterisation over other treatment options include simplicity, low cost, no need for hospitalisation or for additional specialist equipment and training, reduced necessity for general anaesthesia and lowered risk of complications associated with surgical approaches. In this case, anaesthesia was necessitated due to the foal being very reactive and resented handling of the head, even when sedated.

This case appeared to involve bilateral tympany, although it is reported that unilateral tympany is more common, and difficult to distinguish from bilateral involvement. Unilateral tympany can cause swelling in the parotid region on both sides, but generally the affected side can be expected to be more distended than the other (McKinnon et al, 2011). This foal had bilaterally symmetrical swelling, and when each of the left or right catheters were pulled out during treatment, ipsilateral swelling recurred, supporting the diagnosis of bilateral tympany. The guttural pouches were not entered prior to treatment, which would have confirmed if the affliction was in-fact bilateral. And in fact, guttural pouch endoscopy is recommended in such cases to assess for presence of secondary conditions such as empyema (Caston et al, 2015).

References Blazyczek, I., Hamann, H., Ohnesorge, B., Deegen, E., Distl, O. (2004). Inheritance of Guttural Pouch Tympany in the Arabian Horse, J Hered, 95(3), 195-199.

Carrick, J., Begg, A. (2008). Peripheral blood leukocytes, Vet Clin Nth Amer Eq Pract, 24, 239-259.

Caston, S., Kersh, K., Reinertson, E., Cammack, S. (2015).

Treatment of guttural pouch tympany in foals with transnasal Foley catheter placement, Eq Vet Edu, 2015(27), 28-30.

Freeman, D. (2006). Guttural pouch tympany – a rare and difficult disease. Eq Vet Edu, 18(5), 234-237.

Freeman, D. (2008). Complications of Surgery for Diseases on the Guttural Pouch. Vet Clin Nth Amer Eq Pract, 24(3), 485-497.

Greet, T. (2015). Managing foals with guttural pouch tympany.

Eq Vet Edu, 27(1), 31-33.

McKinnon, A., Squires, E., Vaala, W., Varner, D. (2011). Equine Reproduction, Wiley-Blackwell, Oxford, pp. 612-613; 664.

Taylor, P., Clarke, K. (2007). Handbook of Equine Anaesthesia, Elsevier Saunders, New York, 123-175.

Walton, R. (2013). Equine Clinical Pathology, Hoboken, Wiley. 130.

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50 Eq Vet Pract March 2022; 47(1)

OBITUARY

Peter D Rossdale OBE, MA, PhD, Dr. (h.c.) BERNE, Dr. (h.c.) EDIN, DVSc (h.c.) SYD, DESM, FANZCVSc, FRCVS 1927-2021 Excerpted for EVP from a full access Editorial by EVJ Editor Celia Marr and EVE Editor Tim Mair, in Equine Veterinary Education 2022; 34(2): 60-64* https://beva.onlinelibrary.wiley.com/doi/10.1111/eve.13609 Peter Rossdale was first and foremost a clinician. He Edinburgh, Berne and Sydney, honorary membership of attained an honours degree in natural sciences from the BEVA in 1978 and Honorary Fellowship of the ANZCVSc University of Cambridge in 1949, then graduated from the in 1975, and with numerous prizes and honours including Royal Veterinary College, London, became MRCVS in the John Henry Steel Memorial Prize, the William Hunting 1952 and, after 2 years in Sussex, Prize and the George Fleming he took up a position as an equine Prize, the Tierklinik Hochmoor practitioner in Newmarket where he International Prize, the Dalrymple remained for the remainder of his Champneys Prize and Cup, clinical career, retiring in 2004. He the Duke of Devonshire Award was awarded his Fellowship of the for contributions to the British RCVS in 1960 for work performed Breeding Industry and the BEVA in practice describing the clinical Equine Welfare Award. He was features of the newborn foal, data inducted into the University of which he published, unusually Kentucky’s Equine Research Hall for a practitioner in those days, of Fame and received the OBE in a pair of papers in the British for services to equine veterinary Veterinary Journal*. Completing science. his portfolio of academic degrees, Peter lectured extensively and this Peter gained the degree of PhD included many inaugural lectures in Hunt et al., Vet Rec 2022; 189(12): 483. from the University of Cambridge https://doi.org/10.1002/vetr.1308 the UK and abroad, including the for his published work in the field Peter Wilson Bequest Lectureship in Edinburgh and in of equine perinatology and reproductive biology in 1985.

1978, the D.L.T. Smith inaugural lectures in Saskatoon He also wrote and edited numerous veterinary textbooks, and the Frederick Hobday Lecture in the UK in 1985 including Equine Stud Medicine, written with his partner, and cumulating with a comprehensive review of equine Sidney Ricketts; a textbook read by every undergraduate perinatal illness in his 2004 AAEP Milne Lecture, The of the 1980s who aspired to a career with horses.

Maladjusted Foal: Influences of Intrauterine Growth However, Peter Rossdale’s massive and lasting impact Retardation and Birth Trauma. on the equine veterinary profession of today lies in his Peter was amongst a small group of equine practitioners vision, his commitment to the education of others and who, in the late 1950s, developed what ultimately became his drive towards improving standards in clinical practice.

BEVA in 1961. He held the positions of Treasurer (1961– Yet, vision alone is not enough: implementation can be 1962), Chairman of Programmes Committee (1973–1975) the bigger challenge and Peter had a unique ability and President (1976). Arguably his most pivotal role for to form collaborative groups and to motivate them to BEVA was as Editor of Equine Veterinary Journal (EVJ), improve equine clinical practice, turning his visions into a position he held from 1979 to 2010 and thereafter as reality. Peter was generous with his knowledge, and he EVJ’s Emeritus Editor. happily shared information and expertise with anyone and Peter was fascinated by the philosophy of science and everyone willing to learn. This earned him the respect of indeed read extensively on scientific method, psychology both the veterinary profession and academia, recognised and the process of decision making. He believed ‘the duty with additional honorary degrees from the Universities of

Eq Vet Pract March 2022; 47(1) 51

of clinicians to publish is one which, in many respects, is as strong as that of the duty of care of the individual patient’. Core beliefs which Peter wrote on frequently was that research should seek to address clinically relevant questions and that cases seen in practice were a fruitful source of both pertinent questions and valuable data. He wrote a fascinating summary of these principles in an EVJ article published in 1975 in which he explained the fusion of clinician and researcher which characterised his entire career. In this article, he wrote: ‘In any appraisal of the subject of research we must ask ourselves the question why is it interesting to find out. The clinician in equine practice is faced with a scarcity of clinical data on which to make a diagnosis. Clinical research can elevate the art of the clinician and contribute to the aggregate of knowledge within the profession’. In the same article, he went on to summarise the benefits of engaging in research which practitioners could access under the headings (1) more accurate diagnosis, (2) more satisfaction from work, (3) the currency of interests - summarising his appreciation of the benefits of working with others, and (4) opportunity of travelling where he addressed his pleasure in being able to attend international meetings, share ideas with clinicians and researchers of like mind and gain transferrable knowledge of clinical approaches adopted elsewhere. These points, made over 40 years ago describe his career-long ethos of working with others, from a private practice setting, to gain and share knowledge to improve our ability to provide for the horses under our care.

Peter’s first publication appeared in the Lancet, reporting seizures in newborn foals, and drawing parallels with human neonatal illness. This became the underpinning theme of much of his subsequent research effort. This marked the start of a career as an author of clinical research which ultimately led to the publication of around 150 research papers based primarily on clinical data generated from his caseload and a further 100 or so editorial and educational articles relating to both clinical practice and academic publishing*.

Peter was consistently innovative throughout his long tenure with the Equine Veterinary Journal. He was not EVJ’s first editor, this honour falling to Col. John Hickman and then Leo Jeffcott succeeded him before Peter took on

this challenge in 1979. However, Peter was undoubtedly its most influential editor. Under Peter’s watch, EVJ evolved into the leading international journal for equine veterinary science, and it performed consistently well in the citation indices for veterinary sciences. His life-long belief in the importance of practice-generated research was more widely articulated by the evidence-based (veterinary) medicine movement of the 2000s; although it clearly amused him greatly that this discipline was extolled, by some more passionate adherents, as a novel approach to practice. Peter had been talking, and writing, about the same principles for almost 50 years by that time.

Peter was committed to veterinary education at all levels. He recognised that a scientific journal created a key archive of data to support change in practice, but there was an additional need to help support learning within the profession. To meet this need, he established Equine Veterinary Education in 1989, pointing out, in EVE’s first editorial that ‘Practitioners cannot afford to leave education at the gateway of graduation for fear of becoming old-fashioned and redundant’. By engaging the support of both BEVA and AAEP for EVE and by ensuring that motivated younger colleagues took on the challenge of editing and contributing to EVE, Peter was able to rapidly develop the journal into the most important education journal for equine practitioners in existence, combining both novel case reports with authoritative clinical commentaries and review articles which are essential reading for every practitioner who seeks to keep up to date with developments in the field.

Every equine clinician who has practised since the 1960s owes Peter Rossdale a debt of gratitude. His recognition that practice must be based on science and that science has a central place in daily clinical practice, his vision and drive to improve the world he found himself in, and his ability to motivate others to help him implement that vision has created a legacy in the form of the two journals he was instrumental in developing, EVJ and EVE that have and will continue as a central role in equine practice long beyond Peter’s retirement. It is all the more surprising to consider that he did this in his spare time, in parallel with a busy and successful career as a Thoroughbred practitioner and clinical researcher.

* A full appraisal of Peter’s clinical research endeavours and publications can be viewed in the Obituary published as the Editorial in Eq Vet Edu 2022; 34(2): 60-64 https://beva.onlinelibrary.wiley.com/doi/10.1111/eve.13609. Further collegial praise for Peter’s lifetime of clinical practice also is offered in Hunt M, Ricketts S, Digby NW et al. Peter Daniel Rossdale. Vet Rec 2021; 189(12): 483-484. https://doi.org/10.1002/vetr.1308.

52 Eq Vet Pract March 2022; 47(1)

Cre8ive 9311

MASSEY EQUINE HOMEPAGE HEADS DOWN, TAILS UP The beginning of the year seems busier as we seek to cope with practice and teaching demands with fewer veterinarians in New Zealand. On the heels of the veterinary shortages experienced by the profession during the pandemic, Massey has sought to further engage with the Government to financially support the training of more veterinarians. Although negotiations are sensitive and take time, early indications are that class size will increase in the near future. However, agreement on final student numbers is still in negotiation.

This year has seen a significant change in the format of the equine roster delivered to final year students at Massey. After much consultation, review, and hard work, we have moved towards a “competency-based framework”. With this change comes more focused development and assessment of day one skills and more timely feedback processes to support the professional education of our students. Our goal is to produce more “practice ready” graduates using a range of educational tools in a blended learning experience.

PEOPLE

with us. Congratulations to Luca Panizzi, one of our equine surgeons, recently promoted through Massey’s internal processes. Later this year, Luca celebrates 10 years of service at Massey University. Recently Charlotte Bolwell received a Teaching Award from the College of Sciences at Massey University.

OUTREACH Ben Sykes and Amy Lovett visited VS Equine in Hawkes Bay in December. The team at VS Equine participated in a training session on Equine Gastric Ulcer Syndrome and gastric endoscopy. Chris Riley and MUVERT team have been on frequent standby for the recent flood and storm damage that has plagued the country in January and February.

RESEARCH With each newsletter, we do our best to inform EVP readers about the research conducted by or in collaboration with Massey Equine academic clinicians and researchers. Some of these findings are important to the New Zealand equine industry, whereas others have global implications. Many are now published online in open access forums to make these findings more accessible to veterinarians and horse owners.

However, many of the best research ideas come from private practice and industry. Please contact us if you need advice on study design, applying for research funding, or potential collaborators. Emma Gordon, Erica Gee, Chris Rogers and Charlotte Bolwell have received a MURF Early Career grant to investigate “Environmental leptospirosis at the Massey University Large Animal Teaching Unit”.

RECENT PUBLICATIONS We are happy to introduce our new Practising Veterinarian in Equine Medicine, Hannah Burrows. Born and raised on the North Shore of Auckland, Hannah developed a passion for horses at a young age. She spent most of her younger years riding and competing around New Zealand and Europe before commencing studies at Massey University. Following graduation from Massey in 2020 (BVSc (Dist.)), Hannah completed an equine internship at Veterinary Associates Equine in Auckland before joining us in January. “I am excited to step into the ambulatory and general equine practitioner role at the university”. Outside of work, Hannah enjoys hiking in summer, skiing in winter or on a rainy day, baking in the kitchen. She will help students achieve the day one competencies required for general equine practice in her new role.

Ben Sykes returned to Australia late last year for a well deserved break with his family. He continues to support the clinical teaching programme from afar until his next visit 54 Eq Vet Pract March 2022; 47(1)

Gibson, M J, Roca Fraga, F J, Bolwell, C F, Gee, E K, Rogers, CW. (2022). Race-level reporting of incidents during two seasons (2015/16 to 2016/17) of harness racing in New Zealand. Animals, 12(4), 433. https://doi.org/10.3390/ ani12040433 Riley CB, Rogers CW, Thompson KR, Guiver D, Padalino B. A survey-based analysis of injuries to horses associated with transport by road in New Zealand. Animals 2022, 12(3), 259; https://doi.org/10.3390/ani12030259 Gordon SJG, Bolwell CF, Raney JL, Zepke N. Transforming a didactic lecture into a student-centered active learning exercise—Teaching equine diarrhea to fourth-year veterinary students. Education Sciences. 2022; 12(2):68. https://doi. org/10.3390/educsci12020068 Legg KA, Cochrane DJ, Gee EK, Rogers CW. Physical activities of jockeys during a working week. Comparative Exercise Physiology 2022; 18 (1): 75-83.

Chin, YY, Rogers, CW, Gee, E K, Stafford, K J, Cameron, E Z. (2022). The pattern of breeding and management within the New Zealand Thoroughbred breeding industry 2005–2015. 1.

The stallion population. Animal Production Science. https://doi. org/10.1071/AN21388 Rogers CW, Gee EK, Dittmer KE. Growth and bone development in the horse: when is a horse skeletally mature?

Animals 2021; 11(12): :3402. http://doi:10.3390/ ani11123402 Aldrich ED, Cui X, Murphy CA, Lim KS, Hooper GJ, McIlwraith CW, Woodfield TBF. Allogeneic mesenchymal stromal cells for cartilage regeneration: A review of in vitro evaluation, clinical experience, and translational opportunities.

Stem Cells Translational Medicine 2021; 10 (11): 1500-1515.

Lambe H, Sykes, BW. Prevalence of salmonella faecal shedding in at-risk hospitalised cases in an equine hospital in New Zealand: A pilot study. Equine Veterinary Education 2021; https://doi-org.ezproxy.massey.ac.nz/10.1111/eve.13573 Fernandes KA, Rogers CW, Gee EK, Fitch G, Bolwell CF, Kittleman S, Bermingham EN, Thomas DG. Comparison of gastrointestinal transit times in stabled Thoroughbred horses fed freshly cut pasture and three conserved forage-based diets. Animal Production Science 2021; https://doi-org. ezproxy.massey.ac.nz/10.1071/AN20695 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

Warm Regards from the Massey Equine Team

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

E equinevets@massey.ac.nz

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Eq Vet Pract March 2022; 47(1) 55

Aleman, M et al. Caecal microbiota in horses with trigeminal-mediated headshaking. Vet Med Sci. 2022 Early view https://onlinelibrary.wiley.com/doi/10.1002/vms3.735?af=R The aim of this study was to investigate if gastrointestinal microbiota in the cecum is different in horses with trigeminalmediated headshaking (TMHS) compared to a control population, during a summer season with clinical manifestations of disease. Five geldings with TMHS and five neurologically normal control geldings suffering orthopedic disease were sourced from the authors institution and kept under the same husbandry and dietary conditions. All horses were fed orchard grass hay for 30 days before being euthanized. Caecal samples for microbiota analysis were collected within 20 min after euthanasia and microbial sequencing was performed using an Illumina MiSeq platform. The caecal microbiota of horses with TMHS was similar to control horses in terms of diversity but differed significantly with Methanocorpusculum spp. having higher abundance in horses with TMHS. However, this difference may be an incidental finding due to small population size.

NOTE: we have so much to learn about intestinal, and other, bodily microbiota, and of course in this trial one does wonder what effect orthopaedic pain and previous therapy may do to these intriguing microbial populations?

Zimmerman, M et al. CT is a feasible imaging technique for detecting lesions in horses with elbow lameness: A study of 139 elbows in 99 horses. Vet Radiol Ultrasound 2022; Early view https://doi. org/10.1111/vru.13044 One hundred thirty-nine elbows of 99 Warmblood horses (median age, 9 years), 16 with elbow pain and 123 control elbows, were included. Osseous cyst-like lesions (n = 13), only seen in the proximomedial radius and medial humerus, were the most common cause of lameness in horses with elbow pain (n = 16), with significantly higher grades of bone resorption, including osseous cyst-like lesions, in this group. One elbow had an avulsion fracture of the lateral epicondyle, two others showed signs of osteoarthritis. Significantly higher grades of sclerosis in the proximomedial radius were seen in horses with elbow pain. However, mild to moderate subchondral bone sclerosis was seen in all horses at the medial aspect of the joint. Osteochondral fragmentation lesions of the weight-bearing surface of the medial radius (2/16 vs 1/123; P = 0.0025) and intra-articular gas (4/16 vs 2/123; P < 0.0001) were significantly more common in horses with elbow pain compared to control horses. Mild linear resorptive subchondral bone lesions were often not clinically relevant (32/123 vs 5/16 in medial humerus; 19/123 vs 2/16 in medial radius). Elbow CT is a feasible method for detecting clinically relevant lesions in adult Warmblood horses with elbow pain.

Lutzer, A et al. Effects of blue monochromatic light directed at one eye of pregnant horse mares on gestation, parturition and foal maturity. Dom Anim Endocrinol 2022; 78: 106675. https://doi. org/10.1016/j.domaniend.2021.106675 Twenty mares with singleton pregnancies were studied over 2 consecutive years in a cross-over design. In 1 year, mares received an extended photoperiod using 50 lux of blue LED light (468 nm) directed at a single eye from 08:00 until 23:00 daily via head-worn light masks starting mid-December. In the other year they remained as untreated as control subjects. Gestation was shorter in blue LED light-treated than in control pregnancies (median 333.0 vs 338.5 days, P = 0.036). Foals born to blue LED light-treated mares had lower wither heights (median 103.0 vs 104.5 cm, P = 0.023), similar weights (median 55.8 vs 54.8 kg, P = 0.732) and took less time to stand after birth than control foals (median 35.0 vs 53.5 min, P = 0.036). Foals born to blue LED light-treated mares had reduced hair length compared to controls (median 12.0 vs 20.0 mm, P = 0.009) and hair regrowth in treated mares was reduced (P = 0.036). Blue LED light directed at one eye thus appears to advance foaling and to influence height and hair coat but not weight in foals.

SISTER ORGANISATION PUBLICATIONS AVAILABLE

The latest Equine Health Update from the SAEVA is available HERE to view.

And all copies of Australian Equine Veterinarian are available on SciQuest HERE to browse.

56 Eq Vet Pract March 2022; 47(1)

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SISTER ORGANISATION PUBLICATIONS AVAILABLE The latest Equine Health Update from the SAEVA is available HERE to view.

And all copies of Australian Equine Veterinarian are available on SciQuest HERE to browse.

Eq Vet Pract March 2022; 47(1) 57

SURVEILLANCE REPORTS BIOSECURITY NEW ZEALAND

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.

Digested from Surveillance, June 2021; 48 (3) PDF available on SciQuest HERE

SUSPECTED EQUINE EXOTIC DISEASES Paul Bingham Paul.Bingham@mpi.govt.nz

Accessed and edited from Surveillance 2021; 48 (4): 10-24

EQUINE HERPESVIRUS MYELOENCEPHALOPATHY CONFIRMED A veterinarian called the MPI exotic pest and disease hotline to report mild neurological deficits in the hindlimbs of a heavily pregnant brood mare. The affected mare was in the same paddock as a mare that had aborted 12 days earlier and Equine herpesvirus-1 (EHV-1) had been detected by PCR on fetal lung tissue. The property had experienced an outbreak of equine herpesvirus myeloencephalopathy (EHM) in February 2014, with the neuropathogenic genotype D752 confirmed (McFadden et al. 2016). A few months after the 2014 EHM outbreak and immediately prior to the following foaling season, two mares on the farm aborted, one at 9 months and one at 10 months gestation. The cause of abortion in both cases was confirmed to be EHV-1 with the same genotype as in the EHM outbreak (McFadden et al. 2016). Since that time the farm has carried out comprehensive EHV-1 vaccination of all mares. At the time of this notification the affected mare was otherwise bright, alert and eating well. On clinical examination she had hindlimb muscle fasciculations and mild weakness with ataxia on circling or stepping. This mare subsequently aborted and, with little improvement in the neurological deficits, was euthanased. The remaining nine paddock mates showed no neurological signs and went on to foal normally. Nasal, blood and fetal tissue samples from the neurological case were submitted to a commercial veterinary laboratory and EHV-1 was detected by PCR in

58 Eq Vet Pract March 2022; 47(1)

both the nasal swab and fetal tissues. Further investigation and management of the case was co-ordinated by the farm veterinarian, in consultation with the New Zealand Equine Health Association (NZEHA; https://www.nzeha.org.nz/) and MPI incursion investigation team. Samples from both aborted fetuses and the neurologically affected in-contact mare were submitted to the AHL (Wallaceville) for virus isolation and molecular analyses.

The farm instituted strict quarantine measures following the NZEHA biosecurity code (NZEHA 2022). Virus isolates obtained from aborted fetuses underwent molecular sequencing, which identified EHV-1 with the amino-acid coding change of the DNA polymerase (D/N752) associated with an increased risk of neurological disease (Nugent et al. 2006; Oladunni et al.

2019). It should be noted, however, that only about 80 percent of EHV-1 strains from horses with clinical EHM have this genetic indicator. It appears that many factors apart from the viral strain, including sex, age, immune status, reproductive status and stage of gestation, and perhaps the route of transmission, determine the clinical manifestations and variable incidence of EHM associated with EHV-1 infection (Oladunni et al. 2019). To inform disease management, the veterinarian instituted a high level of molecular and serological surveillance, including two rounds of nasal swabs and acute and convalescent blood sampling of all horse cohorts on the farm. In addition, mares and stallions were closely monitored with tail sensors that constantly recorded their body temperatures. No further horses were affected, and foaling proceeded normally, with no further premature births or abortions. Repeated PCR testing of nasal swabs found no further evidence of EHV-1, and serological screening by ELISA identified no seroconversion. The early and efficient implementation of quarantine and other biosecurity controls appeared to have helped contain spread: there was no evidence of spread of the

virus to in-contact horses, and in consultation with NZEHA and MPI, after 28 days biosecurity protocols were relaxed, and the investigation was closed.

EQUINE INFECTIOUS ANAEMIA AND EQUINE VIRAL ARTERITIS EXCLUDED A veterinary pathologist contacted MPI to report a suspect exotic disease in a Southland racehorse. The Thoroughbred mare had developed limb oedema after training. Serum amyloid A was mildly increased (60 mg/L; reference range 0–8 mg/), indicating a low level of systemic inflammation. Serum was sent to the AHL for exclusion of exotic causes of equine oedema including Theileria equi, Babesia caballi, equine viral arteritis virus and equine infectious anaemia virus.

All these agents were excluded by serology. The veterinarian noted that this was the second horse in the stable to develop similar signs, and that the oedema seemed to be related to infected lower-limb abrasions sustained on the training track.

This was considered a likely pathogenesis of the oedema and, together with the serology results, excluded exotic agents as the cause of disease.

A pathologist at a commercial veterinary laboratory called the exotic pest and disease hotline to report that a 10-yearold Thoroughbred mare had been losing weight over the previous 3–4 weeks and now had clinical signs including dependent oedema of the head and lower limbs. The mare had been referred from a private veterinary clinic to Massey University Veterinary Teaching Hospital at Palmerston North for a diagnostic workup. The presentation was potentially consistent with an arteritis that might be caused by exotic agents including equine arteritis virus (EAV) and equine infectious anaemia (EIA) virus. Serum submitted to the AHL (Wallaceville) tested negative by AGID test for EIA, and negative by VNT for EAV. In addition, serum was tested by cELISA, which enabled the exclusion of the exotic agents Theileria equi and Babesia caballi. The mare improved temporarily but then developed a septic carpal arthritis and deteriorated. She died and a full postmortem was carried out. Pathological changes were evident in multiple organs and systems, including hepatitis, nephritis, dermatitis (pruritic epidermal ulceration and crusting affecting predominantly the head, neck and distal limbs), and fibrinosuppurative (septic) arthritis and tenosynovitis of the right carpal joint. The skin, kidney and liver changes were characterised histologically by multifocal eosinophilic granulomas and/or eosinophilic, lymphocytic and plasmacytic infiltrates. The main lesions present in this case were considered likely to have been multifactorial, including equine multisystemic eosinophilic epitheliotropic disease (MEED). Some of the clinical signs and lesions present in this case such as anorexia, weight loss, severe pruritus, subcutaneous oedema, exfoliative eosinophilic dermatitis and eosinophilic inflammation on internal organs such as the liver, were consistent with those described in horses with MEED (Black & Mace 2004; Bosseler et al. 2013). The case described here did not demonstrate a blood eosinophilia, which was consistent with

a case series described in the literature where only 6/44 (14%) had eosinophilia (Bosseler et al. 2013). Although the pathogenesis is not well established, according to some authors recurrent episodes of type 1 hypersensitivity associated with ingested, inhaled or parasitic antigens may be involved in the development of MEED (Pucheu-Haston & Del Piero 2013). Exotic disease was excluded and the investigation closed.

An equine veterinarian in Canterbury notified MPI of an unusual case of anaemia in a 6-year-old male castrated Warmblood horse. Causes of anaemia are many and include exotic infectious diseases such as equine infectious anaemia (EIA), equine viral arteritis (EVA) and equine piroplasmosis.

Whole blood and serum from the horse were obtained, and testing excluded EIA, EVA, Anaplasma phagocytophilum and the equine piroplasms Theileria equi and Babesia caballi. Further workup by the veterinarian indicated that the horse was suffering from right dorsal colitis, and treatment to support this condition was instituted. The horse gradually improved, and the investigation was closed.

An equine veterinarian in Ca nterbury contacted the incursion investigation team to report severe thrombocytopaenia in a 13-year-old Warmblood mare. The mare had developed sudden inappetence and depression, and on bloodwork was found to be anaemic (haematocrit 0.23; normal range 0.33– 0.55) with a panleucopaenia and increased fibrinogen (9 g/L; normal range 1-4 g/L). Exotic infectious causes of anaemia in horses include equine viral arteritis (EVA) virus, equine infectious anaemia (EIA) virus, the bacterium Anaplasma phagocytophilum and the equine piroplasms Theileria equi and Babesia caballi. Serum and whole blood from this mare were obtained for testing, and assays were negative for all these agents. The mare’s condition further deteriorated, and she developed a severe thrombocytopaenia and mild nasal epistaxis. She was euthanased and a full necropsy was performed. Histology showed the absence of cellular bone marrow, suggestive of an aplastic process, which would explain the mare’s disease process. Exotic agents were excluded and the investigation was closed.

EQUINE INFLUENZA EXCLUDED An MPI Verification Services veterinarian called MPI via the exotic pest and disease hotline to report that a recently imported Thoroughbred gelding had spiked a fever on the last day of 2 weeks quarantine at a Transitional Facility in Auckland. There were no other clinical abnormalities.

The imported cohort was retained in quarantine pending diagnostic testing to rule out the possibility of exotic disease and to try and find the cause of the pyrexia. Nasal swabs and blood samples sent to the AHL returned negative PCR test results for influenza A, equine arteritis virus and equine piroplasmosis. ELISA test results were negative for equine piroplasmosis (Theileria equi and Babesia caballi), and the AGID test was negative for equine infectious anaemia virus. Two blood samples were taken 24 hours apart and tested at a commercial veterinary laboratory, where they

Eq Vet Pract March 2022; 47(1) 59

revealed an initial slight neutrophilia with left shift, indicative of inflammation, which then returned to normal. Biochemistry showed mild non-specific abnormalities. The horse’s faeces softened during testing, and the vet was suspicious of a mild self-limiting colitis. The cohort was released following the horse’s full return to normothermia and results from the exotic disease testing.

[NOTE: Could this have been a case of equine coronavirus disease?]

BABESIA CABALLI EXCLUDED An AHL scientist contacted MPI to report a positive test for Babesia caballi in a healthy 4-year-old Thoroughbred gelding being prepared for export to Singapore. To meet access requirements, horses must return negative cELISA results for both B. caballi and Theileria equi. The horse had returned a low-titre positive result in the cELISA test for B. caballi. Repeat blood samples were collected from the gelding 3 weeks later and submitted for follow-up testing at the OIE Collaborating Centre for Surveillance and Control of Animal Protozoan Diseases at Obihiro University of Agriculture and Veterinary Medicine in Hokkaido, Japan. The horse was confirmed negative to B. caballi by IFAT, competitive ELISA and nested PCR testing methodologies carried out at the OIE reference laboratory, and subsequently was able to travel to Singapore. Equine piroplasmosis was excluded and the investigation was closed.

References McFadden AMJ et al. (2016). The first reported outbreak of equine herpesvirus myeloencephalopathy in New Zealand.

NZ Vet J 64(2), 125–134.

New Zealand Equine Health Association (2012) Biosecurity Code for the control of Equine Contagious Diseases. https:// www.nzeha.org.nz/. Accessed 15 Feb 2022 Nugent J et al. (2006). Analysis of equid herpesvirus 1 strain variation reveals a point mutation of the DNA polymerase strongly associated with neuropathogenic versus nonneuropathogenic disease outbreaks. J Virol 80(8), 40474060.

Oladunni FS, Horohov DW, Chambers TM (2019). EHV-1: A Constant Threat to the Horse Industry. Front Microbiol 10, 2668.

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EQUINE CLINICAL DIAGNOSTIC LABORATORY CASES Accessed and edited from Surveillance 2021; 48 (4): 24-33

IDEXX LABORATORIES Two Quarterhorse mares on a Queenstown-Lakes property presented with diarrhoea. Blood tests revealed low selenium levels in both, at 1,180 and 1,060 nmol/L (reference range 1,600–3,260 nmol/L).

60 Eq Vet Pract March 2022; 47(1)

A 4-year-old Thoroughbred filly in Kapiti presented with coughing. Cytological evaluation of a tracheal wash sample revealed a neutrophilia with moderate numbers of bacteria (coccobacilli), both extracellularly and intracellularly (within neutrophils). Cultures yielded a moderate growth of gramnegative rods that were identified by MALDI-TOF mass spectrometry as Raoultella terrigans. This soil bacterium is closely related to other genera of enterobacteria, particularly Klebsiella. It is a rarely reported medical and veterinary opportunistic pathogen. Reports in the medical literature speculate that it has a role in device-associated nosocomial opportunistic infections and is thus related to multi-drug resistance.

[NOTE: It is important to study neutrophil cytology in order to get a better handle on the significance of a positive TTW culture (Jocelyn et al. 2018)].

SVS LABORATORIES In early July, a mare from Bay of Plenty was examined for suspected chronic mud fever lesions on white parts of both the hind pasterns and fetlocks. The lesions were not improving and biopsies were taken. Histopathology revealed erosive and ulcerative dermatitis with a superficial dermal vasculopathy, suggestive of pastern leukocytoclastic vasculitis. The exact pathogenesis of this syndrome is not known, but the lesions may represent a common pathological response to a number of insults including immune dysregulation, superficial bacterial infections with such organisms as Staphylococcus spp., drug reactions, and photosensitivity, but can be idiopathic. In many cases the lesions involve only non-pigmented skin of distal extremities.

A 19-year-old Clydesdale gelding from Hawkes Bay presented with a quittor wound. A swab from the affected site yielded a moderate growth of Staphylococcus aureus and a light growth of E. coli. The S. aureus isolate was resistant to cefoxitin in vitro and therefore consistent with a methicillin-resistant Staphylococcus aureus (MRSA). This isolate was also resistant to tetracycline and gentamicin.

In early September a 3-week-old foal from Waikato presented with respiratory signs. Consolidated lung tissue was seen on ultrasound, and purulent material was present in a tracheal wash. Cytology of a tracheal wash sample revealed suppurative inflammation with intracellular and extracellular cocci and short rods. On culture there was a heavy growth of Rhodococcus equi.

GRIBBLES VETERINARY PATHOLOGY An 8-year-old Miniature horse mare in Waikato had a mass on the flank that was 4 x 3 cm, subcutaneous, and attached to underlying muscle but with the overlying skin freely mobile. Histopathological examination of a biopsy revealed fibrous connective tissue and muscle disrupted by numerous eosinophils and scattered pockets of neoplastic mast cells, consistent with a mast-cell tumour.

Mast-cell tumours are uncommon in horses and when they do occur, they are typically low-grade and tend to expand locally but only rarely metastasise.

examination. All three of the smears examined contained hundreds of live and dead mites in various stages of maturity.

The morphology of the mites was consistent with a Chorioptes species, most likely Chorioptes bovis (formerly C. equi), consistent with a diagnosis of chorioptic mange. This is the most common cause of mange in horses and occurs in all breeds, but draught horses are predisposed. Lesions are pruritic and most commonly affect the distal limbs. Initially, papules develop, followed by alopecia, crusting and, in chronic cases, a moist dermatitis.

A fixed sample of third eyelid from a 13-year-old Quarterhorse cross gelding from Auckland was submitted for histopathological examination. One area of the conjunctiva was expanded by broad anastomosing cords and sheets of dysplastic epithelial cells. The cells were pleomorphic, displaying nuclei of variable size and shape, and there was keratinisation and necrosis of individual cells. These findings were consistent with ocular squamous cell carcinoma in situ. The third eyelid and limbic bulbar conjunctiva are common locations for squamous cell carcinoma in horses and, as in other species, ultraviolet light is thought to play a role in their development. It is thought that there may also be genetic risk factors in certain breeds. Often pre-cancerous lesions are present in both eyes. These progress to squamous cell carcinoma in situ and then become locally invasive.

Metastasis is uncommon and may be restricted to the local lymph nodes but can be seen a long time after treatment of the initial lesion.

A subcutaneous mass adjacent to the carpus of a 10-yearold horse from Westland was excised and submitted for histopathological examination. It consisted of an infiltrate of neoplastic mast cells with many eosinophils and scattered foci of necrotic eosinophils. Although only infrequently seen, mast-cell tumour is nevertheless one of the more common skin tumours of horses.

-------------------------------------------------------------------References Jocelyn NA, Wylie CE, Lean M, Barrelet A, Foote AK. Association of neutrophil morphology with bacterial isolates in equine tracheal wash samples. Equine Vet J. 2018; 50(6): 752-758. doi: 10.1111/ evj.12837.

A 10-year-old Gypsy x Welsh Cob gelding from Canterbury had longstanding skin inflammation of the pastern regions.

Skin scrapings were submitted to the laboratory for cytological

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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

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See the latest NZERF BULLETIN HERE

62 Eq Vet Pract March 2022; 47(1)

NEWS AND VIEWS NZVA AWARDS

CELEBRATING VETERINARY EXCELLENCE Adapted from VetScript October/November 2021; 34(5): 13 Each year the NZVA recognises significant accomplishments, exemplary leadership, and tireless commitment to the veterinary profession through its awards. For 2021 Joe Mayhew was recipient of the NZVA President Award.

Joe Mayhew was one of the first veterinarians to graduate from Massey University in 1968. According to Brian Goulden, who taught him at the time, he was an exceptional and memorable student. Always curious, with a mind like no other. Joe is now recognised by veterinarians in New Zealand and around the world as a legend in equine neurology and large animal medicine.

He is a Diplomate of the ACVIM and board certified in both large animal internal veterinary medicine and neurology. He is also a Fellow of the Royal College of Veterinary Surgeons and a Diplomate of the European College of Veterinary Neurology.

Currently Joe a Professor Emeritus in the Massey School of Veterinary Science and has been awarded a Massey University Doctor of Science for his exceptional published work in equine medicine and neurology. He has also published extensively in veterinary neurology, equine medicine, and comparative neuropathology. Joe has contributed prolifically to research and education and has held influential roles at several veterinary schools around the world. In the UK he served on the Council of

the Royal College of Veterinary Surgeons disciplinary, specialisation and education committees and acted as an RCVS external examiner. He was president of the European Society of Veterinary Neurology for two years and served on its management committee and as an examiner.

Joe has been a passionate supporter of and contributor to the New Zealand Equine Veterinary Association throughout his career. He took on the role of editor of the NZEVA Equine Veterinary Practitioner with enthusiasm, brilliantly navigating its transition to an online publication that not only meets and exceeds the needs of equine veterinarians in New Zealand but is also a fun and enjoyable read.

In 2015 Joe was inducted into the University of Kentucky Equine Research Hall of Fame for his contribution to equine medicine and neurology. Inductees are selected by an international committee after nominations by peers, and selection is a rare honour. In addition, he now is a life member of the NZEVA and the British Equine Veterinary Association and in 2021 was awarded The ACVIM Robert W. Kirk Award for Professional Excellence.

Joe’s contribution to veterinary education in New Zealand and internationally, plus his clinical and research studies, has had a major impact on neurology and equine health and welfare worldwide.

THE CLINICAL COMPANION OF THE DONKEY 2nd edition This book is available FREE to download by registering HERE or at: https://www.thedonkeysanctuary.org.uk/what-we-do/for-professionals/ resources/clinical-companion

Eq Vet Pract March 2022; 47(1) 63

JOCKEY CLUB FACT BOOK RELEASED The US Jockey Club has released its 2021 Edition of the Fact Book.

The online Fact Book is a statistical and informational guide to Thoroughbred breeding, racing and auction sales in North America that also features a directory of international organizations including NZ Thoroughbred Racing.

Of some note is that import/export and sales trends have been affected by the COVID-19 pandemic. When compared to 2019, the 2020 imports decreased 23%, exports decreased 36%, and mean yearling price decreased 20%.

NEWS RELEASE THE JOCKEY CLUB NEWS SERVICE

8 JAN 2022

aravit@jockeyclub.com

LEADING US INDIVIDUAL & PARTNERSHIP BREEDERS FOR 2021 RANKED BY TOTAL PURSE EARNINGS Name Godolphin Calumet Farm Stonestreet Thoroughbred LLC WinStar Farm, LLC Ramsey Kenneth L. Ramsey Sarah K. Hertrich Fred W. III Jones Brereton C. Gary & Mary West Stables Inc. Juddmonte Farms Inc

Starters 275 560 163 326 262 262 202 230 161 79

Starts 1285 3532 897 2021 1711 1711 1105 1411 1009 416

Wins 195 472 160 331 237 237 164 189 155 84

Seconds 183 470 142 262 243 243 139 207 153 74

Thirds 186 510 116 272 226 226 149 209 144 63

Earnings-US$ 20,654,816 16,105,109 13,351,710 12,027,208 7,376,432 7,376,432 7,282,297 6,943,733 6,787,244 6,428,413

US THOROUGHBRED RACING ECONOMIC INDICATORS JANUARY 2022 VERSES JANUARY 2021 SARS-CoV-2 caused US TB racing prize money and number of race days to slump in 2020, but wagering has bounced back for first half of 2021 when compared to figures from 2019, pre-CoViD-19..

Indicator Wagering on U.S. Races* U.S. Purses U.S. Race Days U.S. Races U.S. Starts Average Field Size Average Wagering Per Race Day Average Purses Per Race Day

64 Eq Vet Pract March 2022; 47(1)

January 2022 $942,654,762 $82,103,062 259 2,186 16,949 7.75 $3,639,594 $317,000

January 2021 $960,160,298 $71,098,677 255 2,211 17,879 8.09 $3,765,335 $278,818

% Change -1.82 +15.48 +1.57 -1.13 -5.20 -4.12 -3.34 +13.69

ELECTRONIC COPIES OF E-EVP 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

McInturff, C et al. An Alternate Radiographic Guided Technique for Injection of the Equine Navicular Bursa Using a 40 mm (1.5-inch) 20-Gauge Needle: A Pilot Study. J Eq Sci 2022; 108: 103775. https://doi.org/10.1016/j.jevs.2021.103775 The aim of this study was to describe an alternate radiographic guided technique for injection of the equine navicular bursa using a 40 mm (1.5-inch) 20-gauge needle and compare the success rate, needle redirection rate, and rate of inadvertent synovial penetration between operators with 1 year, 8 years, or >30 years of experience in equine veterinary medicine. There was no significant difference in success rate between operators regardless of level of experience or hoof configuration, and inadvertent penetration of other synovial structures was highly unlikely.

Fig 2(b), McInturff et al. 2022

Falomo, ME et al. Behavioral and hormonal effects of 2 weaning methods in trotter mares. J Vet Behav Clin Appl Res 2020; 36: 47-53 https://doi.org/10.1016/j.jveb.2019.10.005 In stud 1 (S1) with 10 mares, weaning was performed around 5 months post-partum, two foals/week, and mares put to paddock after separation. In stud 2 (S2) with 12 mares, weaning was performed around 7 months post-partum, all foals on the same day, and mares put into indoor individual stalls for two days after separation. Behavioral observations and saliva and hair sampling for RIA cortisol assay were taken on day minus-7, day 0 (weaning day), day 7, and day 30. Mares in both studs ate the least on day 0 (P < 0.001). On day 0, vocalizations and locomotion were higher than in any other day (P = 0.003 and P = 0.045, respectively) and higher than in the other stud (both P < 0.001) in S1 and S2, respectively. Saliva cortisol concentrations showed weak, but significant, correlations with eating, stall pacing, pawing, and vocalizing. Results suggest that artificial weaning could be a stressor for mares in both groups. Mares whose foals were weaned earlier did not show more stress-associated changes in behavioral or endocrine parameters than those whose foals were weaned later but housed more restrictively for two days after weaning.

NOTE: Results in a sister paper from this group looked at the effect of two different weaning systems (https://doi.org/10.1016/j. jveb.2021.10.008), suggesting that being weaned two at a time at 5 months of age could be more stressful for foals than being weaned all together at 7 months of age. There are many uncontrolled variables and biases in such uncontrolled studies.

Shaffer, SK et al. In vitro motions of the medial and lateral proximal sesamoid bones under mid-stance load conditions are consistent with racehorse fracture configurations. J Biomechan 2022; 130: 110888. https://doi.org/10.1016/j.jbiomech.2021.110888 To address whether in three-dimensions, proximal sesamoid bone (PSB) motions relative to the opposing metacarpal condyle during simulated mid-stance loads contributed to PSB fractures, 7 equine cadaveric forelimbs were axially loaded to simulate standing and mid-stance walk, trot, and gallop load conditions (1.8-10.5 kN). Joint angles were determined by tracking the positions of bone-fixed kinematic markers. Internal-external rotation, abduction-adduction, and flexion-extension of each PSB relative to the third metacarpal condyle were compared between loads and between PSBs. The medial PSB rotated externally and the lateral PSB apex abducted during limb loading. Medial PSB external rotation was significantly greater at the gallop than at the walk or trot load conditions. The medial and lateral PSB motions observed in this study are consistent with location of fatigue damage and fracture configurations frequently seen in medial and lateral PSBs from TB racehorses. More specifically, medial PSB external rotation is consistent with the development of an abaxial subchondral medial PSB lesion that is reported in association with medial PSB transverse fracture, whereas lateral PSB abduction is consistent with axial longitudinal fracture of the lateral PSB.

Eq Vet Pract March 2022; 47(1) 65

DRUG POSER See how you respond to our clinical poser involving this formulation of an antimicrobial compound. https://www.sciencebuddies.org/

DEPOT (LONG-ACTING) PENICILLIN-G Stephanie Brooks | equine@matamatavets.co.nz Regarding the long-acting penicillin-G formulations for systemic use in horses: What are the usual constituents of depot-penicillin-G combination drugs?

Aqueous solution containing 150,000 IU procaine penicillin-G and 150,000 IU benzathine penicillin-G per mL What class of drug is penicillin-G? A first-generation beta-lactam, naturally occurring antibiotic that is inhibited by acid when given PO. What is the main spectrum of activity of this combination of penicillins?

Penicillins have excellent activity against most gram-positive bacteria (notably ß-haemolytic streptococci) and most anaerobic organisms with the notable exception of Bacteroides fragilis.

Some gram-negative bacteria such as Actinobacillus spp. and many Pasteurella spp. are also susceptible to penicillin-G. What is the manufacturer-recommended dose regimen?

Total dose of 12-22mg/kg IM SID or BID. Administration IM into neck, pectoral, or gluteal muscles. Penicillin is a time-dependent antibiotic so a dosing interval of 12h for IM use is normally recommended for optimal bactericidal effect.

What are the manufacturer-recommended indications for its use?

Infections of deep wounds, lower respiratory, urinary tract and uterine infections; can be used by local infusion for latter.

Preferred antimicrobial for treatment of tetanus and strangles (if treatment required). Drug of choice for all ß-haemolytic streptococcal infections.

From page 27

Is long-acting penicillin combination drug an effective substitute for procaine penicillin-G use in horses?

Long-acting penicillin contains procaine penicillin G and longacting benzathine penicillin. During the first 12 hours these can reach the MIC concentration required, after this however the long-acting benzathine penicillin does not reach required MIC. Therefore long-acting penicillins are generally not appropriate for use in horses.

What are the most frequently encounted adverse reactions?

Penicillin allergy: This is a hypersensitivity reaction to the penicillin molecule, which is in both procaine penicillin G and benzathine penicillin. This manifests as urticaria, angioedema and anaphylaxis including systemic hypotension and circulatory collapse, with varying degrees of bronchoconstriction leading to dyspnoea. This usually occurs 10-30 minutes after administration.

These horses should not be treated with penicillin in future.

Procaine toxicity: CNS-related locomotor and behavioural changes which occur during or immediately after the injection due to intravascular absorption of procaine. These horses can be administered procaine penicillin in future. Care must be taken in all horses to ensure the procaine penicillin is not being administered intravascularly. Administration immediately post-exercise or when the horse is stressed can increase vascular absorption and likelihood of inadvertent intravascular absorption, therefore is not recommended.

Colitis: Like most common antibiotics, penicillin use can cause antimicrobial-associated colitis. This risk is furthered with oral administration due to poor oral absorption resulting in penicillin concentrating in the intestinal lumen, changing the normal gastrointestinal flora.

VETLOGIC PUZZLE - ANSWER BAND

ALBUM TITLE

TRACKS

Rangitikei Rongeurs

Haemorrhaging

12

Southland Swabs

Anastomuzacs

13

Rocking Rectal

10

Bloody Nuisance

11

Hamilton Haemostats Canterbury Clamps

66 Eq Vet Pract March 2022; 47(1)

See page 29 for puzzle

THERIOGENOLOGY CLINICAL POSER

Babiche Heil | babiche@matavet.co.nz From page 27 While examining the fetal membranes of a mare after a normal foaling you notice the structures pointed out by the white arrows on the chorioallantois in figures A and B. The structures are ~2 cm long.

(i),

What are these structures?

These structures are chorioallantoic pouches.

(ii),

What is their significance?

Chorioallantoic pouches are small, pedunculated outgrowths arranged in a circle on or near the umbilical cord attachment.

They hang as folds and represent invaginations into the allantoic cavity. Inspissated endometrial cup material and epithelial debris may accumulate in the pouches giving them a more round or cystic appearance (B). These pouches are normal findings when examining an equine placenta post-foaling.

Bozorgmanesh, R et al. Symmetric dimethylarginine concentrations in healthy neonatal foals and mares. J Vet Int Med 2021; 35(6): 2891-2896 Serum and EDTA whole blood samples were collected by ‘convenience sampling’ from 104 mares in their last month of pregnancy and then from mares and 125 foals at <12 hours and 2, 7 and 30 days postbirth. Upper limits for SDMA concentrations in foals were above the adult horse reference interval and decreased from 70 mu g/dL (range, 7-100 mu g/dL) to 18 mu g/dL (range, 6-27 mu g/dL) during the first few weeks of life.

NOTE: There does appear to be quite a wide biologic, breed and laboratory variability in results for SDMA testing (e.g. https://pubmed.ncbi.nlm.nih.gov/33524207/) so it would be unwise to rely solely on this measurement as evidence of renal GFR dysfunction in equids just yet. See conclusion in Gough and McGovern (2021) below.

Gough, RL and McGovern, KF. Serum symmetric dimethylarginine (SDMA) concentration in healthy neonatal Thoroughbred foals. Eq Vet J 2021; 35(6): 2891-2896. https://doi.org/10.1111/jvim.16295 Reference ranges are established in healthy adult horses (≤ 14 µg/dL) and concentrations are increased in horses with acute kidney injury (median 32 µg/dL; range 15-92). Blood samples were collected from 120 TB foals 1-34 hours old. Median value (95% CI) for SDMA concentration was 69.0 µg/dL (63.0, 75.0; range 35.0-376.0). A cut-off value of 168 µg/dL would include 95% of individuals and is therefore suggested. Serum SDMA concentration was correlated with age (R = -0.3, P = 0.003), creatinine concentration (R = 0.6, P ≤ 0.001) and urea concentration (R = 0.3, P = 0.002). Neonatal foal SDMA concentration is higher than in adult horses, than in older foals and then in adults with acute kidney injury. Therefore, currently SDMA cannot be used as a marker of renal dysfunction in this age group.

Further work is required to assess whether SDMA concentration is increased in neonates with renal disease and, if so, what cut-off should be used.

Eq Vet Pract March 2022; 47(1) 67

Pusterla, N et al. Investigation of Three Newly Identified Equine Parvoviruses in Blood and Nasal Fluid Samples of Clinically Healthy Horses and Horses with Acute Onset of Respiratory Disease. ANIMALS 2021; 11(10: 3006. https:// www.mdpi.com/2076-2615/11/10/3006 Three novel equine parvoviruses (equine parvovirus hepatitis (EqPV-H), equine parvovirus CSF (EqPV-CSF) and equine copivirus (Eqcopivirus)) have recently been discovered in horses with respiratory signs. Nasal fluid samples and blood from 667 equids with acute onset of fever and respiratory signs were analyzed for the presence of common equine respiratory pathogens as well as for the novel parvoviruses; 87 clinically healthy horses served as controls. Samples from 117/667 sick horses tested qPCR-positive for at least one of the three parvoviruses. Co-infections with common respiratory pathogens and parvoviruses were seen in 39/667 sick equids. All 87 clinically healthy horses tested qPCR-negative for all tested common respiratory pathogens, and 10/87 healthy horses tested qPCRpositive for one of the equine parvoviruses. It was suggested that the three novel equine parvoviruses did not contribute to the clinical picture of equids with respiratory disease in the sample population.

Bookbinder, L and Schott, HC. Refeeding syndrome in a miniature donkey. J Vet Emerg Crit Care 2021; 31(5): 668673. https://pubmed.ncbi.nlm.nih.gov/34259376/ Refeeding syndrome developed in an aged miniature donkey gelding during treatment of suspected enterocolitis. Hypophosphatemia was seen as ileus and neuromuscular weakness despite a 3-day history of hyporexia, increased body condition (7/9), and adherence to nutritional recommendations for critically ill equids including nasogastric enteral feeding with a commercial equine diet. Hypophosphatemia of <0.16 to 0.3 mmol/L [reference 0.5–1.4 mmol/L] developed despite this enteral supplementation and was ultimately corrected by intravenous administration of sodium phosphate solution. It was suggested that risk factors for refeeding syndrome in equids may be broader than previously recognized and include critically ill equids at risk for insulin dysregulation that may have unique nutritional co-morbidities and requirements. Revised best-practice nutritional guidelines and improved supplementation products are required to improve equine critical care.

Magalhaes, HB and Canuto, LEF. Electrolytes and pH of Mammary Gland Secretions Assessments to Detect Impending Parturition and Associations with Placental and Neonate Features in Donkeys. J Eq Vet Sci 2021; 102: 103636. https://doi.org/10.1016/j.jevs.2021.103636 Each multiparous jenny (n = 37) had mammary secretion assays and gestational and parturition variables documented. Mammary secretion pH profiles assessed visually and classified as fast pH drop (1), slow pH drop (2), and alkaline pH (3) as previously described for horses. The overall gestation length was 374 ± 8.7 days [range 357 to 390 days]. There were no differences for gestation lengths for jennies delivering colts (374 ± 2.1, range 357-385 days), versus those delivering fillies (373 ± 2.3 range 358-390 days). The ratio of foal birthweight to dam bodyweight was 10%, and the ratio to fetal membrane weight was 11%. There was a significant reduction in Na+ and an increase in Ca2+, Mg2+, and K+ concentrations leading to foaling. The pH showed a 90% sensitivity for foaling within 24 hours, whereas the specificity was 70%, and the PPV and NPV values were 40% and 97%. Of interest, Ca2+ (>10 mmol/l) displayed a sensitivity and specificity of 71% and 85%, whereas the PPV and NPV were 72% and 84%. Also, 65% of the jennies displayed slow pH drop and foaled with a mean acidic pH of 6.4 ± 0.02. Conversely, 32% of the jennies showed a fast pH drop from day minus-1 (7.3 ± 0.2) to the day of foaling with an average pH of 6.6 ± 0.08. One jenny foaled with high pH = 7.5. There were weak and negative correlations between pH and Ca2+, Mg2+ and K+ (P<.05). In addition, Ca2+ displayed a weak but significant correlation with Mg2+, Na+ and K+. Thus, daily pH measurements of the mammary gland secretions can predict foaling in jennies, whereas Ca2+ was not as useful. Contrary to horses that most mares present a fast pH drop profile, most jennies showed a slow pH drop profile. The sex of foal did not affect the gestational length and fetal/maternal and fetal membrane proportions in donkeys.

Geurden T et al. Three-year study to evaluate an anthelmintic treatment regimen with reduced treatment frequency in horses on two study sites in Belgium. Vet Parasitol 2021; 298: 09538. https://doi.org/10.1016/j.vetpar.2021.109538 A reduced treatment frequency anthelmintic regimen was evaluated on 2 studs in Belgium over 3 seasons. Previously ivermectin (IVM) was used <4 times a year with moxidectin (MOX) used >6 times a year with reduced egg reappearance periods detected in some of the treated horses. In the present study, all horses were treated with IVM or MOX in the spring and in autumn. Faecal egg counts (FEC) were conducted every two weeks and when >250 epg that horse was treated with pyrantel embonate. No increase in parasitic disease over the three-year period was observed. A cyathostomin life-cycle model was used to evaluate long term effects of various treatment regimens and this indicated that the whole-herd treatment regimen with at least 4 macrocyclic lactone treatments annually led to 2–3 times faster development of resistance than any of the alternative treatment regimens [1 or 2 IVM or MOX, plus PYR for hi-shedders].

Further lowering the treatment frequency or applying even more selective treatments enhanced the delay in resistance development, but to a lesser extent.

68 Eq Vet Pract March 2022; 47(1)

MINING FOR MUSIC THE AMAZING RHYTHM ACES

Dancing the Night Away

https://www.youtube.com/watch?v=gCQhP_KeQv4 to listen to Blue Moon Revisited while you read on.

Searching for great music is like mining for opals. You are in the dark for a long time and then a flash of brilliance illuminates your life. The light radiated for me in a Hereford street bar in Christchurch in 1983 watching Russell Smith and The Amazing Rhythm Aces live. The experience is still vivid after 40 years.

The Aces came together in Memphis Tennessee in 1972.

Joining lead vocalist and guitarist Russell Smith, were bassist Jeff "Stick" Davis, drummer Butch McDade, keyboardist Bill Earhart III, lead guitarist Kelvin Holly, multi-instrumentalist Barry Byrd Burton, and pianist James Hooker.

The beauty of this band is the way all these great musicians work together. No one tries to outdo the other and you get to experience the separate beauty of piano, keyboard, mandolin, fiddle and guitar all held together by subdued, beautiful drums and percussion. Each musician has space and time to play their part separately, with wonderful instrumental backing quietly coming through, all topped off by Russell Smith’s distinctive gravelly voice. They have something really special as a group. Somehow the restraint in the music from notes not played adds to the performance rather than detracting from it. They recorded many wonderful tracks, and the first I have picked is one of their lesser known numbers but it highlights the wonderful way they all worked together to produce really memorable music. When you watch the clip, you see how they are living a musical experience rather than just performing.

Sadly, Russell Smith died in 2019 but his legacy remains. If you think Country Music is lightweight have a wee listen and become enlightened. Before you turn up the volume settle into a fine aged Kentucky bourbon. I recommend the Labrot and Graham, Woodford Reserve (Distillers Select). This is triple distilled in copper pots and produced by the oldest bourbon distillery in the USA. Beautiful.

Try and stream this from your computer to your TV so you can get some real volume.

I have added here two extra tracks to give you an excuse to top up the bourbon:

•

Last letter home - Russell Smith with Walt Wilkins https://www.youtube.com/watch?v=aIgEj-tYRZE

•

Anger and Tears - Russell Smith https://www.youtube.com/watch?v=no04riWonJo

Dancing The Night Away - The Amazing Rhythm Aces

https://www.youtube.com/watch?v=gCQhP_KeQv4

James Brown & Russell Smith Standin' beside of the ocean Lookin' out across the water Everythin' is beautiful But I still don't feel like I oughta

Still I remember The way you held me And all the sweet things you used to say When we were two young lovers Dancin' the night away

Things we wanted, not so long ago I got 'em all now, babe But I ain't got you no more

Standin' beside of the ocean Lookin' out across the bay I should look for companionship But it just gets in my way

Still I remember The way you held me And all the sweet things you used to say When we were two young lovers Dancin' the night away

All the lights are flickerin' Out along the shore I see people dancin' there But I just don't dance no more

I remember everythin' Dresses you used to wear You were so light and graceful You seem to float right through the air

Still I remember The way you held me And all the sweet things you used to say When we were two young lovers Dancin' the night away

Me I looked so funny dancin' But you loved me anyhow Now I wish I could find somebody To love me like that now

Let me see you dance Let me see you dance Oh, babe, let me see you dance I can still see you dance I remember you dancin' Oh, babe, let me see you dance

BB Feb 2022

Eq Vet Pract March 2022; 47(1) 69

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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70 Eq Vet Pract March 2022; 47(1)