Alex Gough MA VetMB CertSAM CertVC PGCert MRCVS

Head of Medicine Referrals, Bath Veterinary Referrals

Alex graduated from Cambridge University Vet School in 1996 and achieved RCVS certificates in Small Animal Medicine and Veterinary Cardiology, as well as a human Postgraduate Certificate in Neuroimaging for Research from Edinburgh University. He worked in mixed, mainly small animal practice for six years, then in referral practice, seeing referrals in medicine, cardiology and neurology, with a particular interest in medical neurology. He is the author of Differential Diagnosis in Small Animal Medicine (2007), has written a column summarizing the latest research for the Veterinary Times since 2003 as well as chapters on neurology and clinical genetics in two BSAVA manuals, and sits on the advisory clinical board of a large veterinary group. In his spare time, he writes historical fiction novels and plays guitar.

Alison Thomas BVSc, Cert SAM, MRCVS

Senior Veterinary Surgeon, Victoria Hospital, Blue Cross

Clinical Leadership Team, Blue Cross

Alison graduated from Liverpool University in 1987 and has spent most of her career working in charity small animal practice. After two years in private practice in Aylesbury, she moved to Asia, spending two years in private practice in Singapore, followed by seven years at the SPCA in Hong Kong. Since 1998 she has worked at Blue Cross in Victoria, London, becoming Senior Veterinary Surgeon in 2007 and joining the newly formed Clinical Leadership Team of Blue Cross in 2016. She gained the RCVS Certificate in Small Animal Medicine in 2001, and was awarded Advanced Practitioner Status in Small Animal Medicine in 2017. In her spare time she enjoys hiking, travelling and reading.

Dan O’Neill MVB BSc(hons) GPCert(SAP) GPCert(FelP) GPCert(Derm) GPCert(B&PS) MSc(VetEpi) PhD MRCVS

Senior Lecturer, Companion Animal Epidemiology, Royal Veterinary College

After graduating from Dublin Vet School in 1987, Dan worked in industry and general practice for 22 years, latterly running his own companion animal practice in Petts Wood, Kent, for 12 years. During these years, he was awarded additional qualifications in pharmacology, general practice, dermatology, feline practice and business management. In 2009 he undertook an MSc supported by BBSRC and then a PhD supported by the RSPCA in veterinary epidemiology at the RVC to develop the VetCompass programme of primary‐care veterinary clinical research. After postdoctoral posts supported by Dogs Trust and Kennel Club Charitable Trust, Dan was appointed as Senior Lecturer in Companion Animal Epidemiology at the RVC in 2017. As well as teaching and publishing, Dan focuses on expanding VetCompass internationally, with particular emphasis on breed‐related health. In his spare time, he is a keen ITF taekwondo enthusiast and currently holds a 2nd Dan black belt.

For anyone interested in the health and welfare of dogs and cats, there are few topics that engender such emotional energy, diverse opinion and heated debate as the potential negative impacts of selective breeding on canine and feline disease occurrence, and the optimal ways to manage and/or eliminate such impacts. But energy, opinion and debate can only bring true positive change when they are based on good evidence. In this respect, the third edition of Breed Predispositions to Disease in Dogs and Cats is hugely timely. The book comes not only at a time of increasing awareness of the impacts that breed characteristics may have on health, but also when there is growing appreciation of the glaring underuse of objective data to support traditional perceptions and opinions which have become accepted as ‘fact’ in breeding folklore and veterinary science. This book aims to remove the roles of speculation, opinion and anecdote from the discussion on breed health issues and instead to refocus and underpin these discussions based on solid evidence‐based principles.

There is no doubt that the Bateson Report on pedigree dog health and its far‐reaching recommendations (Bateson, 2010), the creation of the Royal College of Veterinary Surgeons’ RCVS Knowledge initiative to promote the generation and application of veterinary clinical evidence (RCVS Knowledge, 2017) and a general increase in commitment to evidence based veterinary medicine over the past decade have resulted in a greater appreciation of the need for reliable evidence on the health impacts of breed characteristics in dogs and cats. Fortunately, this awareness of the need for valid evidence has coincided with the development of exciting new tools which allow us to collect and interpret large volumes of relevant data from primary and referral veterinary practices and to analyse these in robust and less biased ways. As a result, for the first time, we are increasingly able to provide some reliable real‐world context to the likely impact of breed characteristics on animal health and welfare. The development and international adoption of standardized systems of nomenclature such as the VeNom initiative (VeNom Coding Group, 2017) and ground‐breaking research tools such as the Royal Veterinary College’s VetCompass Programme (VetCompass, 2017) allow researchers to explore vast amounts of clinical data from first‐opinion and referral veterinary practices. These developments have transformed how we can investigate companion animal diseases and their impact on animals, their owners and their breeders. The era of ‘Big Data’ for companion animals and its impact on animal health and welfare is now truly upon us.

Realization of the powers from developments such as these means that this new edition of Breed Predispositions to Disease in Dogs and Cats really does herald a new and more valid perspective in our understanding of the types of disorders and their likely impact on different dog and cat breeds. The new edition has been completely rewritten using ‘evidence‐based veterinary medicine’ criteria that are applied to international data and consequently provides an accurate reference resource on disease predispositions that is relevant to breeds from all corners of the world. The information is comprehensive and detailed but presented in a readily understandable and searchable format. Prevalence, odds and risk ratio values, as well as study design details, are provided so that the more motivated reader can go beyond an awareness that a predisposition has been reported and start to examine the context and strength of the reported associations. This book truly is a cornucopia of breed health information.

This third edition will become an invaluable and constant resource for students, vets, breeders, owners, scientists and indeed anyone interested in companion animal welfare. We are privileged to live at a pivotal tipping point in the generation and application of evidence for better decision‐making in companion animal health. This book will play a key role in centralizing our current knowledge into a single resource, and is thereby a torch‐bearer that will finally enable us to move beyond endless circular discussion to positive action that will benefit the welfare of our cats and dogs.

It is widely accepted that almost all dog and cat breeds have specific diseases to which they are particularly prone (i.e. predisposed). Indeed, many textbooks and published research papers include lists of breed predispositions as a standard feature when describing specific disease conditions. To extend this focus, the first edition of Breed Predispositions to Disease in Dogs and Cats, published in 2004, aimed to provide a single reference resource for breed predispositions that would better illuminate our understanding of breed health (Gough & Thomas, 2004). The concept for the first edition was born during discussions between the two original authors (Alex Gough and Alison Thomas) while preparing for their RCVS Certificate in Small Animal Medicine exams in 2001. This book was the first of its kind to focus purely on breed‐specific predispositions and was widely welcomed by academics, veterinarians, breeders and owners. That original edition was compiled mainly from secondary sources of evidence such as textbooks, reviews and conference proceedings and did not provide detailed reference citations for all the breed–disease combinations reported. The second edition, published in 2010, redressed many of these shortcomings and was updated with more recent publications while also ensuring that every cited disease had at least one supporting reference. However, much of the disease information still came from secondary sources such as textbooks, review articles and conference proceedings. The implication of this was that the second edition was substantially reliant on expert opinion. At that time, almost a decade ago, this approach may have been acceptable, but as we progress into the modern age of evidence‐based veterinary medicine (EBVM), expert opinion is now generally considered to be weak evidence, and reliance should instead be placed on the results of original research (Holmes & Ramey, 2007).

In consequence, preparations began for a third edition that would have a strong emphasis on improved academic rigour, better compliance with the modern principles of EBVM and a sound epidemiological infrastructure. To meet these lofty aspirations, Alex and Alison enlisted Dr Dan O’Neill to join as a third co‐author, to ensure high epidemiological standards and also to reduce the individual workload for each author. Dan is an epidemiologist working on the VetCompass Programme at the Royal Veterinary College (VetCompass, 2017), but with that rare academic attribute of essentially still being a general veterinary practitioner. We are confident that this third edition has achieved our academic goals – but we must also sadly report that we failed in our aspiration to reduce the workload. Indeed, it was quite the reverse, as the new perspectives introduced by Dan entailed a complete rewrite. Ah well, you can’t win them all – but we do hope that you enjoy the end result of our combined labours.

For this new edition, we have consulted and referenced primary sources of evidence almost exclusively (i.e. the original published papers that reported the primary research) and have restricted inclusion to just those diseases where primary research identified sufficient evidence for the existence of a breed predisposition. As might be expected, this new approach led to some challenges and several discussions between the authors on the optimal threshold of evidence for disease inclusion. During our rewrite, we became painfully aware of just how little evidence actually exists for much of what we may ‘believe’ to be true about companion animal health. When we examined the literature closely, many of the predispositions commonly reported as ‘knowns’ in textbooks and introductions to peer‐reviewed publications had very little, if any, reliable supporting evidence. This realization reinforced our determination that the new edition should follow rigorous evidence‐based principles, but it also meant that the new book would entail a total rewrite, with substantial work required to freshly identify those diseases with and without a solid evidence base. We found ourselves painfully deleting many conditions that had been included in the previous book based on expert opinion but which lacked adequate evidence. ‘Believing in a predisposition’ and ‘having evidence for a predisposition’ are not always the same thing. The positive side of our new EBVM approach, however, was a refreshing discovery that our new detailed trawl of the primary literature led us to identify many new breed–disease combinations that had not made it into the previous two editions. This may have been because the predisposition was first reported after the second edition was published or because our previous reliance on expert opinion had failed to uncover the association.

Our new search methods and inclusion criteria are described more fully in the Methods section. We hope that these changes support a more robust and defensible evidential and scientific body of information in this third edition, which also includes additional supporting information for breed predispositions where possible. Such additional information may describe the population studied in the original papers – such as geographical location, referral or general practice population (many academic papers are based on referral populations, and their results do not necessarily generalize well to the populations of patients commonly seen in general practice) – while the date of the referenced papers may assist with a perspective on the temporal relevance of the results. Information is also provided on the comparator populations used in the studies (e.g. crossbreds or all study dogs) and the numerical results, which show the strength of the reported predisposition (e.g. odds ratio or prevalence). Taken together, these new segments of information should help the reader to piece together the likelihood of the reported predispositions being real and relevant in relation to his or her own personal animals and interests. In the first and second editions, the research was divided between the authors by body system. For this third edition, we have instead divided the research alphabetically by breed. Consequently, some differences in writing style and emphasis may be apparent between the authors’ sections. However, by sticking to pre‐agreed methods, we hope to have maintained a satisfactory level of consistency across the work. We have also updated the genetics section as well as adding new explanatory sections on methods, longevity and epidemiology. We hope that these will give the interested reader some useful background on these topics as well as suggestions on where to find further information as required.

Companion animals are often bred according to the whims and needs of mankind rather than following the harsh survival rules of natural selection, and therefore breed‐related disease has become an important anthropogenic welfare issue. In consequence, it behoves everyone with an interest in companion animals to strive to reduce these animal welfare costs. A critical first step in this process is the need to define which breed–disease combinations (i.e. predispositions) have strong supporting evidence. We hope that the third edition of our book meets this need and provides a solid evidence base from which other companion animal stakeholders can develop effective strategies to improve animal welfare. Breeders and breeding organizations can use this book to identify priorities when considering the genetic health of their breeds. The show community, both those showing and those judging, may use this book to refine their opinions on optimal conformations and temperaments within individual breeds. The strong evidence‐based approach of the book can help veterinary students and veterinarians with diagnosis and when advising prospective and current owners on breed‐specific disease proclivities. Owners may find the book useful when deciding on breed selection or considering on how best to care for their current or prospective dog or cat. Ultimately, this book aims to enhance the welfare of current and future generations of cats and dogs by increasing our awareness of those diseases which commonly affect individual breeds and which may therefore be prevented or diagnosed earlier. Good evidence on breed predispositions empowers us all to combat disease occurrence and should lead to improvements in the lives of our dogs and cats.

We have thoroughly enjoyed writing this book: it became a labour of love for the three of us and consumed our lives for over a year, but we are very proud of the final product. There will obviously be some parts that we will re‐read later and decide we could have done better, and we welcome the reader letting us know about these. There will also be some opportunities that were missed in this edition, and we will be glad to receive suggestions. However, we hope you will forgive these shortcomings for now and simply accept this third edition for what it is: an evidence‐based blueprint for the current state of knowledge on breed predispositions to disease in dogs and cats. We hope you enjoy reading this book.