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In 2004, I got my PhD on the subject 'Breeding against hip and elbow dysplasia in dogs'. My conclusion was that it is possible to breed against these traits and that not much has happened though. The reason was that no systematic selection has in practice been made against these defects. Now, 11 years later, I am glad to see that Finnish breeders have managed to achieve genetic as well as phenotypic gain. St Bernards have also increased their lifespan, as their health has been improving. The Finnish Kennel Club started to estimate breeding values (EBVs) for hip and elbow dysplasia in 2002 for 11 breeds, and during the years, new breeds have been included. At the moment somewhat 55-60 breeds have EBVs for hip dysplasia. It is possible to achieve genetic gain if the breeding dogs are systematically chosen from the better half of the population. There is no need to breed only from animals from the very best hips; just those that are better than the breed average. Progress will be slower, but doing it this way helps maintain genetic diversity.
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Review on ocular surface disorders in brachycephalic dogs
Katariina Mäki posted a blog entry in New Research
A review on ocular surface disorders in brachycephalic dogs has been published in December 2022. This review by Lionel Sebbag and Rick F. Sanchez "offers a summary of the physiological and anatomical features of brachycephalic ocular syndrome (BOS) that predispose brachycephalic dogs to develop ocular surface disease, followed by a concise description of common ocular diseases associated with BOS. It ends with an overview of evidence-based guidelines and animal welfare legislation that some in the veterinary community have already implemented but that requires a wider, international effort in order to reduce the prevalence of BOS-associated disorders and improve the ocular health of affected dogs." (a snippet from the abstract). The review includes also general recommendations - the authors reference breeding programs in the UK and Netherlands, and recommend regular ophthalmologic examinations, which chimes with many countries recommendations. The review is open access and can be read here: https://onlinelibrary.wiley.com/doi/full/10.1111/vop.13054 -
Linebreeding vs. Inbreeding – Let’s be perfectly clear.
Brenda Bonnett posted a blog entry in Brenda's Blog
Linebreeding vs. Inbreeding – Let’s be perfectly clear. Note: This topic was prompted partly by IPFD's participation in the Canine Health Summit put on by Embark Veterinary. See our Q&A article on breeding and genetics topics here. Inbreeding is the mating of related individuals – that is those who have one or more relatives in common. Linebreeding is not simply a form of inbreeding – it IS inbreeding. How close that inbreeding is depends on the selection of individuals within that line. Linebreeding/inbreeding - by definition - reduces genetic diversity. By how much depends on the closeness of mating pairs and the time/number of generations over which the process is repeated. It is scientifically proven and widely recognised that inbreeding/linebreeding in dogs has led to: An increase in the prevalence of inherited disorders A decrease in viability/ longevity A decrease in reproductive ability (reduced fecundity, decreased litter sizes, etc.) The loss of genetic diversity (i.e. decrease in genetic variation) Studies in various species have shown that inbreeding can also result in: developmental disruption, higher infant mortality a shorter life span and reduction of immune system function. And it is known that impaired immune function can lead to higher rates of cancer, and a myriad of other issues for skin, digestive, and other systems as well as resistance to infectious agents. Collectively, these effects of inbreeding/linebreeding are called inbreeding depression. Importantly, inbreeding depression increases as the extent of inbreeding/linebreeding increases. For example, see Inbreeding depression reduces litter sizes in golden retrievers. I was asked by a breeder at a lecture series, during a talk on breeding ethics, “What level of inbreeding is okay? Where is the cut-off for ‘too close’?” I asked the breeder, “Why do you want to do inbreeding/linebreeding? Do you think that will improve health and longevity?” Those at the seminar had previously stressed that their goal was to produce healthy, long-lived puppies. I suggested that inbreeding/linebreeding is generally done to fix certain characteristics in a line - ‘desirable’ characteristics. But what is desirable? Generally, linebreeding is on physical, conformational, or structural characteristics. Not necessarily, and perhaps rarely, primarily on characteristics associated with health and longevity. Therefore, the latter are unlikely to be achieved by inbreeding/linebreeding and will be reduced by the associated decrease in diversity. From the AKC article above: ”Want to add new things to improve the quality of your line? Outcross with a line that has those characteristics you want. Want to be sure to keep the great things you have? Breed closely to get a very consistent litter. When you know what you want, then you can plan to attempt to create the result you desire.” Maybe it is time to be transparent and honest. ‘What you see’ in any pedigree breed – appearance, health, length of life – is ‘what you got’ – a reflection of what was selected for – and what was not selected against – by those who bred them. If your primary goal is to produce healthy, long lived puppies – and that includes all the puppies in all litters – then you would first and foremost mate only from dogs that are themselves healthy, who come from a long line of relatives that are healthy and long-lived; from a long line of dogs that have not exhibited the deleterious conditions listed above as arising from inbreeding/linebreeding or any other conditions of significance in your breed. And you would want to be sure there was a history of great temperaments and breed-appropriate abilities. You would make sure that all the dogs in your line can see, and breath, and move without impediment, and are able to exhibit natural dog behaviours. This is not only the art and science, but the common sense of dog breeding. Once prioritized on those aspects, eliminate from breeding dogs with genetic or other screening results that indicate that they are likely to pass on detrimental traits. After that, only after that, you might do some selection on specific physical attributes. Is all that easy to achieve? No, but who ever said that manipulating the development and genetics of a species should be easy? And, unfortunately, within the breeding populations for many breeds, there may be rather few individuals who are as acceptable as is described above. If what you want is, however, consistency based on physical characteristics, then linebreeding and inbreeding may well give it to you. But, as history has proven, eventually, at a breed level it will often result in the increase in other characteristics, challenges, and issues - not likely to be primarily health and longevity. There are many questions about how to measure genetic diversity, how to determine it – really what is genetic diversity and how do we achieve it? There are no simple answers to those questions. There are major challenges in some breeds where characteristics associated with health and welfare problems are ‘fixed’ and can not be bred away from within a closed population. Here are some facts about genetic diversity: Genetic diversity cannot be achieved by selecting for conformity and consistency in appearance or specific physical traits – i.e. for a lack of diversity in appearance and physical characteristics. In other words, a lack of diversity in observable characteristics reflects a lack of genetic diversity. Eliminating from breeding dogs with variations in ‘minor’ characteristics that are not associated with poor health or function, e.g. many coat colour varieties that are simply deemed as undesirable, will reduce genetic diversity. (Recognizing that a few coat characteristics reflect deleterious mutations or fads. Interested in challenges around coat colours? See Ian Seaths' blog: Systems Thinking and Non-standard Breed Colours.) Diversity will always be reduced by inbreeding and linebreeding – the closer the mating pairs, the longer the linebreeding/inbreeding is followed, the bigger the effect. The ability to increase genetic diversity by breeding only within a closed population is limited, However, calculated measures of diversity may be inaccurate within a registry if only a small proportion of the available population is bred or included in calculations. Pedigree-based calculations of Coefficients of Inbreeding (COIs) – especially on a limited number of generations – underestimate inbreeding compared to genomic based COIs as they are based on average/ predicted inheritance of genetic material from ancestors, rather than the actual case for an individual dog. Measures of genetic diversity are one more tool to inform breeding for the ‘Big Picture’. (See my blog: The Big Picture - in the Dog World as a Whole and for your next Breeding Decision.) What can be done for your breed? There are increasing numbers of breed-specific research studies on genetic diversity. The whole picture for a breed cannot be understood by one calculation or measure done on a limited group of dogs. For an example of a broad-based, global picture, read, e.g.: Genomic diversity and population structure of the Leonberger dog breed. You do not need to focus on the details of the technology and methodology to get the main messages from this paper. For example: "Conclusions: The increasing size of the Leonberger population has been accompanied by a considerable loss of genetic diversity after the bottleneck that occurred in the 1940s due to the intensive use of popular sires resulting in high levels of inbreeding." and "The breed has predispositions to neurodegenerative disorders and cancer, which is likely due in large part to limited genetic diversity." Aaron Sams, expert in genetic diversity at Embark, was responding to a question on the summit that again, was someone knowing how much inbreeding was okay, what level was okay in a breed. And among other sage advice he said that ultimately the breeders and breed club must determine what they can 'tolerate'. And I would add that goes for all aspects of health and lack of it, and longevity issues. Bottom line – you get that for which you select, not that for which you wish. Let’s all be perfectly clear. Other resources on DogWellNet.com: 1. Genetics Vocabulary - Glossary of Terms 2. Relationships between genetics, breeding practices and health in dogs - Grégoire Leroy (France) -
Finnish Kennel Club -- Approaches to Improving Health
Ann Milligan posted a article in Hip Dysplasia
The Finnish Kennel Club News Blog at http://dogwellnet.com/blogs/blog/16-finnish-kennel-club-news/ contains posts which offer information on health management for breeds. -
The Big Picture - in the Dog World as a Whole and for your next Breeding Decision Note: This topic was prompted partly by IPFD's participation in the Canine Health Summit (videos available) put on by Embark Veterinary. See our Q&A article on breeding and genetics topics here. My last blog in 2020 was on the Big Picture in the dog world - it was about Reframing Discussions, globally. Based on our document...the blog describes a webinar and links to presentations discussing all the stakeholders in dog health and welfare and their individual and collective responsibilities. IPFD's great friend and collaborator, Ian Seath has started 2021 also looking at the Big Picture - and the consequences of ignoring it. 2021: Time to see the bigger picture – my January “Best of Health” article - please, read it! Ian gives great examples from the world of dogs and parallels with the Covid situation. I'd like to focus on his comments on health testing, i.e. that a narrow focus on available DNA tests without careful consideration of other health concerns in the breed or line, getting hung up on one mutation and overusing 'clear' sires, and falling in with the marketing ploy that doing all sort of tests is evidence that you are a 'good breeder' are not best practices for breeders. I have just published another blog entitled 'Inbreeding vs. Linebreeding: Let's be Perfectly Clear' where I discuss that topic in the context of the 'art and science' of dog breeding. I worry that not only have many people strayed from an adequate focus on the Big Picture, they may have also dropped common sense as a key component of decision making. Why do people struggle with really embracing the Big Picture or bringing the broader context into decision-making? Do people shut down when presented with complex problems? Can they just not be bothered to think that hard? Are they pressed for time? Maybe it is 'yes' to all of these. But sometimes it is because they just want to do what they want to do and not be faced with a wider responsibility. For example, when legislators come out with dramatic regulations that do not take into account the full situation and are therefore unlikely to fix the real problem and/or likely to have unintended consequences - was it really an oversight or an accident? Or are they mainly focused on an immediate impact and not concerned with long term effectiveness? Do they admit this - at least to themselves? When breeders focus on simple solutions - does that reflect a lack of understanding or is it wishful thinking? For example, wouldn't it be great if just doing DNA tests would discharge their responsibility as a 'good breeder'? Everyone seems to be looking for a silver bullet, simple instructions, black and white do's and don'ts when, in fact, we all know that health, reproduction, mating of dogs, long-term breeding strategies, etc. involve many aspects of humans, animals, biology, genetics...and the one thing it is not and never will be is SIMPLE! And when things go wrong, it hurts people, dogs, and the dog world. One of the issues raised in the webinar on Reframing Discussions is that even within stakeholder groups there is a wide spectrum of individuals and attitudes, beliefs and actions. And that variability is magnified across countries and cultures. It is often difficult for those with a passionate commitment to their own hobby, lifestyle, and relationship with animals to understand and accept the views of others. Consciously or unconsciously. And this leads to judgmental behaviour and rifts. Although it is often a challenge, I try hard to be non-judgmental. It is very clear to me that how dogs and dog breeding is approached, embraced, and regulated even within the show world is very different across regions, e.g., the USA vs. Sweden. I can understand and accept that some have a passionate commitment that dogs are sentient beings with rights (almost) equal to humans while at the same time there are others who 'love dogs' and yet see them as property. That is just the way it is. There is not - and never will be - one ideal for dog breeding; no one definition of best practices. What frustrates me most, however, is when people say one thing, and do something different. Particularly, when their action or inaction leads to suffering - theirs, that of those who buy their puppies, and especially of the dogs themselves. As the popular saying goes, paraphrased, you cannot keep doing things the same way and expect a different outcome. You cannot do linebreeding and increase genetic diversity. It is extremely unlikely that you can make breeding decisions to maximize the likelihood of a win in the show ring and achieve optimal health and longevity in all your dogs, or the breed. You cannot breed dogs with extreme conformation and think their health and welfare will not be affected. As I talk about in the blog on inbreeding, what I hope for is for people to be perfectly clear. It is obvious that individuals and groups, to varying levels across and within countries or within breeds, have come to accept the impacts - for better and worse - that have happened due to selective breeding. Perhaps most feel that the good outweighs the harm, driven by their underlying attitudes and beliefs. Regardless, they accept the situation, they live with it, they may celebrate the good and lament the not so good. Some do not accept it and drop out of breeding or showing. Others may come in to the sport simply accepting the way it is, that challenges are 'normal for the breed'. When I ask breeders to be 'perfectly clear' I am asking them to look at the Big Picture, and really evaluate where they are in it. To be aware of how they function, how they make decisions, and be realistic about the outcomes. Accept that, in the main, barring unfortunate accidents, what you see in your breeds is what people wanted/prioritized in breeding. If you and your club say you want longer-lived dogs with less cancer and that is not happening - it likely means people are not truly prioritizing those goals. Just to be clear. And of course, this is directed at breeders mainly associated with the dog exhibition world. And we are increasingly aware that in many countries, that group produces a minority of the dogs that end up in pet homes. However, challenges in that regard do not release anyone in the 'Fancy' or show world from their responsibility to their dogs, their breeds and dogs in general. Leadership is needed - to benefit all dogs everywhere. There are not simply either good or bad breeders - there are multiple ways to classify those who produce and sell dogs. But for this and some other issues in dog health and welfare we will be more effective at implementing change if we accept that even if we cannot perfectly define 'best' we can probably identify better vs. questionable, and especially some unacceptable practices, attitudes, or characteristics. Then we can eliminate the latter, and promote the positives.
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The increasing availability of genetic screening tests, DNA tests, and now multiplex test panels also requires an understanding of what the tests tell you. Jerold Bell, DVM discusses the practical applications for using the results of these tests to improve the health of dogs, the dangers for the inappropriate use of genetic tests to dog health, and the roles of the breeder, dog owner and veterinarian in utilizing genetic tests. Also see: Essentials of Health Screening and DNA Testing in Dogs - Anita Oberbauer
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Making Assessments of Dogs' Respiration has been produced by the Swedish Kennel Club as part of the work in improving health in pedigree dogs. The film illustrates the causes and background to dogs' respiratory problems and the difficulties to adjust the body temperature. The film discusses the signs of affected breathing that a judge may observe. (English subtitled) Making Assessments of Dogs' Respiration is a complement to the Breed-Specific Instructions for Judges, BSI. Also see: The Breed-Specific Instructions Initiative for Judges (BSI) The Swedish Kennel Club's Breed Specific Instructions (BSI) Programme
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Practical Application of Genetic Testing
IPFD DWN Editor1 posted a article in Tests | Breeding Decisions
Practical application of genetic testing for dogs; test results inform breeding decisions. -
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USA BMD StatisticsRegistrations and Health by Pat Long, May 2019 This file contains statistics for Bernese Mountain Dogs tested for vWD, DM and Antegene's Histio PreTest. Also see the xls... AKC BMD registrations statistics 1937-current.xlsx -
The increasing availability of genetic screening tests, DNA tests, and now multiplex test panels also requires an understanding of what the tests tell you. View this presentation and learn: - The practical applications for using the results of these tests to improve the health of dogs - The dangers for the inappropriate use of genetic tests to dog health - The roles of the breeder, dog owner and veterinarian in utilizing genetic tests
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Maintaining and Improving Breeds Jerold S Bell DVM, Cummings School of Veterinary Medicine at Tufts University [email protected] (This article was published in the September 2016 Perspectives – AKC Delegates Newsletter. It can be reproduced with the permission of the author.)