Death of the Bulldog

It's not a good day for Bulldog breeders and owners - but it might just be a good day for Bulldogs.  A new paper in Canine Genetics and Epidemiology from a team at UC Davis documents the eye-watering lack of genetic diversity in the Bulldog - or English Bulldog as the breed is known globally.

The conclusion? The Bulldog is in big trouble because it does not have enough genetic diversity to allow breeders to breed away from the health problems known to plague the breed.

The story is all over the media here in the UK and internationally - with the above headline in the Independent particularly blunt.

The Indy piece also contains this very strong quote from lead author Professor Niels Pedersen.

“The English bulldog has reached the point where popularity can no longer excuse the health problems that the average bulldog endures in its often brief lifetime."

I think it's fair to say that there has been some small improvements in health, at least in the UK, in recent years. But big problems persist - include breathing issues, an inability to cool themselves, skin, eye and joint problems and an inability, often, to mate or whelp naturally.

Bulldogs are also dead, typically, by the age of six (KC 2014 health survey).

The researchers' aim was to assess if the breed retains enough genetic diversity to correct the genotypic and phenotypic abnormalities associated with its poor health.  The answer? Probably not.

To put it very simply: even if there was a will to breed only from the very healthiest, most moderate dogs (and I'm afraid there isn't because, mostly, people like their Bulldogs just the way they are), you'd only wreck the breed further because it would result in even less of the genetic diversity needed to ensure a healthy life. 

The study found many sections of the Bulldog genome that were identical in every dog they looked at. In particular, they found very little variation in the parts of the genome that code for immune function - very likely the reason the breed suffers a number of immune-mediated issues.

Where does the breed go from here given the increasing pressure on breeders to do more to tackle health problems in the breed

The quickest and simplest option is to outcross - and indeed there are now several varieties of outcrossed Bulldogs (none recognised by the Kennel Club) that can boast a more moderate phenotype and improved health (notably the Leavitt Bulldog which sets a particularly high bar health-wise).

Leavitt Bulldogs     ©Jessica Gilmour/Lonsdale Bulldogs

But of course traditional breeders would rather stick pins in their eyes than cross-breed - and the two dogs above would be considered mongrels by many; no matter that they can run and breathe freely.

Another option could be to... nope, can't think of one. If there isn't enough genetic variety within the breed, outcrossing is actually the only solution.

Leading brachycephalic researcher Dr Rowena Packer (Royal Veterinary College) says the study is a game-changer.

"Our previous research at RVC found that several morphological traits that are actively selected for in this and other breeds, including short muzzles and wrinkled skin, are associated with quality of life limiting health conditions. These problems include lifelong respiratory difficulties and painful corneal ulcers.


"We recommended that breeders should move away from extreme body shapes, and instead select for 'moderate' dogs (with longer muzzles, smaller eyes and less wrinkled skin) within their own breed to avoid associated breathing, skin, eye, reproductive and dental problems.


"However, this recommendation was with the proviso that there was sufficient phenotypic and genetic diversity in the breed, that these new selective pressures would not lead to more problems. This study has demonstrated that the required genetic diversity is unfortunately not present, and thus to obtain healthier body shapes we should strongly consider outcrossing with another, less extreme breed.


"These reforms could allow the Bulldog to see, breathe, eat, birth and move freely, uninhibited by the body shape that we have chosen for them. We need to put health before looks or breed 'purity' to protect the welfare of these dogs. Members of the public who are particularly interested in buying a Bulldog should consider the health problems associated with this breed in its current form, and explore other less extreme breeds with fewer health problems."

I fear, however, that Bulldog breeders will stick their heels in, claiming that their beloved breed is sacrosanct and that everyone is ganging up on them. The researchers will be accused of being secretly funded by PETA; any Kennel Club that acts will be deemed overtaken by animal rights activists and any vet that joins in the cry for reform will be an unreasonable militant who has "got it in for Bulldogs". BVA President Sean Wensley, who appeared on BBC Breakfast this morning highlighting the issues is being widely slated on one Bulldog Facebook group. "He is an ill-informed moron" wrote one commenter. "He needs a good slap" wrote another.

A statement in response to the new study from the UK Kennel Club's Aimee Llewellyn-Zaidi is predictably within the box. First, she suggests that a bigger study is needed in order to get a true picture, saying:

“It would be very interesting to use genomic tools to investigate the bulldog breed on a global level, as it is well-established that breeds that have developed in isolation over time can be utilised to improve over-all genetic diversity and selection for positive characteristics, on a global level.

She goes on to suggest there might be sufficient genetic diversity in the breed in the UK:

"In 2015, a paper published in Canine Genetics and Epidemiology summarised the research undertaken using Kennel Club registered dogs, that estimated the rate of loss of genetic diversity within all 215 breeds of pedigree dog over a 35 year period, and provided information to guide a future sustainable breeding strategy. Latterly in the individual report for the Bulldog the rate of inbreeding declined, implying a slowdown in the rate of loss of diversity, and modest replenishment of genetic diversity which may be through the use of imported animals."

There's a problem with this. All the Bulldogs in the world descend from a small handful of UK founders - and not that long ago either. While it is true that different geographical populations, through a process known as genetic drift, can be a little different genetically it is unlikely to offer much hope in this case. Although most of the dogs sampled in the new study were American, the study did include a handful of dogs from elsewhere (Finland, Canada, Austria, Czechoslovakia, Hungary and Argentina) and found no significant genetic difference.

That said, I can see nothing to be lost by the Bulldog peeps in the UK getting together to donate blood to a further study to see if there is any more genetic diversity in the UK population. Perhaps this is something the KC could help fund?

Professor Pedersen is doubtful that there is much more diversity to be found - but says he would welcome such a move.

"We have done genetic diversity testing on a number of other breeds and have found in every instance that we could identify over 90% of the known diversity with as few as 50-150 dogs," he says. "The more genetically diverse a breed, the more individuals that have to be tested to encompass the existing diversity and the less diverse a breed, the fewer individuals that need to be tested. We are confident that we have identified most of the existing genetic diversity of the English bulldog, but welcome a much wider screening of dogs around the world to identify small bits of diversity that might remain to be discovered.

However, Professor Pedersen disputes the KC's claims that its research showed that Bulldog might be seeing a "modest replenishment of genetic diversity which may be through the use of imported animals"...

He says:

"The [2015 paper by Tom Lewis] confused inbreeding with genetic diversity. The author concluded that dog breeders in the UK have been doing less inbreeding over the last two decades than in the previous decades. The conclusion was that this caused an increase in genetic diversity, when all that it said was that breeders were being more careful in selecting sires and dams that were as unrelated as possible. You cannot increase genetic diversity across a breed by stopping inbreeding because the amount of genetic diversity in any breed is fixed at the time the registry is closed to outside dogs. Therefore, every breed starts with a known amount of diversity and that diversity will either be maintained or diminished by artificial genetic bottlenecks such as inbreeding to a popular show winning sire. You cannot increase diversity of a closed breed without outcrossing. [Prof Pedersen's emphasis] Therefore, dog breeders in the UK are doing a better job maintaining the genetic diversity that currently exists in their breed by avoiding inbreeding, but they are certainly not increasing genetic diversity."

Indeed. And if the KC data shows otherwise it's likely because it only records 3-5 generations of pedigree info for imports, giving a false impression of unrelatedness.

Tom Lewis is a geneticist working with the Kennel Club. He was interviewed today by the BBC's World Service and, encouragingly, did not dismiss outcrossing out of hand. Have a listen here.

Will add more info/statements/responses as I get them so please keep checking back.

In the meantime, here's a clip from the discussion on BBC breakfast in the UK this morning accompanied with an ever-growing number of angry comments from Bulldog breeders and owners defending their breed. Just posted there is this comment from Dr David Sargan and the "brachy" research team at Cambridge University.

"My colleagues Jane Ladlow, Lajos Kalmar, Nai-chieh Liu, I myself, and others at the University of Cambridge have been working with breeders of UK bulldogs and other short faced breeds, doing both genetic and clinical analyses related to one specific problem, the respiratory distress that many of these dogs, (and dogs of other short-faced breeds) suffer from. Our findings agree with those published by Prof Pedersen and his colleagues in that there is little scope for breeding back to a less extreme skull shape whilst staying within the registered population. This is likely to be true of many other aspects of conformation and temperament as well, as we also find large regions without genetic variation in all dogs of the breed. We would agree that the extreme changes in the conformation and appearance (such as the excessive skin rolls in these breeds) do account for many of their disease problems. 

"Fortunately despite the similarities of appearance, not all dogs suffer from the respiratory disorder and although our studies are not yet complete we now have pretty strong evidence that there are still multiple genetic variations between those that do and those that don’t suffer from the disease. But we do not know whether this is also true for other aspects of conformation and appearance related diseases.  

"In summary, I believe that the swiftest way to remove these diseases would be to outbreed to a dog type that does not have to the same degree the conformational features that cause the health problems referred to in this programme. This would certainly be our group’s preferred option. But over the last few years there has been a lot of advice available directed at these health problems and attemting to reduce the popularity of these dogs. What there has not been is the expensive advertising campaign that could bring these problems to public notice. Without it the advice has not got through to the public. We are therefore looking at how we might reduce the problem more slowly by offering advice on how to breed for healthier dogs using the remaining genetic variation within the breed."

All well and good but the problem remains that brachycepahlia doesn't just result in respiratory problems.  There is a huge number of other consequences, including eye injuries, skin-fold issues and a mouth full of crowded, misaligned teeth that is a veterinary dentist's nightmare. Extremely unpleasant for the dogs, too. At the end of the day... we need dogs with longer muzzles.

• 14:30pm: strong press release from the British Veterinary Association.

Vets urge revision of breed standards to protect animal welfare

Following the release of new research data by Niels Pedersen from the Centre of Companion Animal Health, University of California, into breed health of the English bulldog, the British Veterinary Association (BVA) has issued the following statement:

Sean Wensley, President of the British Veterinary Association, said:

“The research released today reflects the seriousness of the health problems associated with English bulldogs that our members are seeing in practice. Revision of breed standards, to include evidence-based limits on physical features such as muzzle shortness, and full consideration of other approaches such as outcrossing, are now needed to ensure high risk breeds, such as the English bulldog, do not continue to suffer unnecessarily.

“Vets are reporting concerning trends in dog health and welfare linked to the rise in ownership of brachycephalic breeds, such as bulldogs, and we are unequivocal in the need for all those with roles to play – including vets, breeders, breed societies, the pet-buying public as well as others – to take action to combat the health problems that brachycephalic breeds experience due to extreme conformation. These issues include severe lifelong breathing difficulties, corneal ulcers, skin disease, a screw-shaped tail which is linked to painful spine abnormalities, and the inability to give birth naturally. As part of their pre-purchase research, prospective dog owners should consider the health harms perpetuated in dogs by purchasing brachycephalic breeds and choose a healthier alternative breed, or crossbreed, instead, and local veterinary practices are ideally placed to give this advice. Brachycephalic dogs should not be seen as cute or desirable, rather as dogs predisposed to a lifetime of poor health, and English bulldogs should not be hailed as a national symbol for the UK where animal welfare is strongly valued.

“Vets have a duty to always prioritise the best interests of their pet patients, which, for affected animals, can involve performing surgical procedures to correct conformational disorders.  They have a concurrent duty to be part of initiatives that aim to address the health and welfare of a breed beyond the individual affected animal. This is why BVA promotes the importance of vets submitting data on caesarean sections and conformation-altering surgery to the Kennel Club, to improve the future of dog health and welfare. We recognise and take seriously vets’ responsibility to develop and contribute to all such initiatives that aim to address the health and welfare of these animals and we will continue to work with all stakeholders who can positively influence and improve the health and welfare of brachycephalic breeds”