Do spayed and neutered dogs get cancer more often?

[Note: this post was originally published at the lovely Julie Hecht's Dog Spies blog at Scientific American.]

Where I live, in America, it’s taken for granted that responsible owners spay or neuter their dogs. The population of homeless animals is still large enough that risking an unwanted litter is, to many owners, unthinkable. And spay/neuter is just what people do. But two papers were published, in 2013 and 2014, suggesting that these widely accepted surgical procedures may lead to increased long-term risk of certain kinds of cancers. These studies ignited a debate which had been smouldering for years: are there unwanted health consequences associated with altering a dog’s levels of estrogen or testosterone?

The 2013 paper looked at Golden Retrievers. The authors reviewed data from veterinary hospitals, comparing Goldens who were diagnosed with various diseases, those who were not, and the spay/neuter status of each group; they found a correlation between spaying or neutering and cancers such as osteosarcoma, hemangiosarcoma, and mast cell cancer. The 2014 paper used a voluntary Internet-based survey to perform a similar investigation in the Vizsla breed. They also found correlations between spay/neuter status and mast cell cancer, hemangiosarcoma, and lymphoma.

These are scary results, but I caution that studying the causes of multi-factorial diseases like cancer is incredibly challenging. Take the Golden Retriever study, a retrospective study using data from a veterinary referral hospital. This study was limited to dogs whose owners chose to bring them to a relatively expensive referral hospital. This is the kind of place where you take your pet when he has cancer and you are willing to spend a fair amount of money to help him. As a result, this hospital’s records probably provide a great source of data on companion animals living with concerned owners, particularly owners who have provided excellent medical care for much or all of the animal’s life. However, this hospital’s records are less likely to provide data on animals whose owners have provided sub-optimal care. This kind of bias in sample selection can have a significant effect on the findings drawn from the data.

The Vizsla study used an Internet-based survey instead of hospital records. Like the Golden Retriever study, this study could have found itself with a biased sample of very committed dog owners, in this case owners who engaged in dog-focused communities online and who had enough concern about the health of the breed to fill out a survey. This study additionally suffered from a lack of verified data; owners were asked to give medical details about their dogs and may have misremembered or misinterpreted a past diagnosis.

Don’t get me wrong – these were both important studies, and they did their best with the available resources. I applaud both sets of authors for putting this information out there. But the studies both have their limitations, which makes their findings difficult to trust or generalize to other populations of dogs.

Meanwhile, another 2013 study presented some other interesting results. This study drew data from multiple referral hospitals to determine the causes of death in spayed or neutered versus intact dogs – and they found that spayed and neutered dogs, on average, lived longer than intact dogs. Intact dogs were more likely to die of infectious disease or trauma, while spayed or neutered dogs were more likely to die of immune-mediated diseases or (again) cancer. In other words, while spayed or neutered dogs did get cancer, it didn’t seem to shorten their lifespans.

This study shed a new light on the cancer question. It suggested that perhaps spayed or neutered animals might be more likely to get cancer simply because they were living long enough to get it. Intact animals were more likely to die younger, perhaps simply not aging into the time of life when the risk of cancer rises.

So where does that leave us? Is there a causal link between spaying/neutering and cancer? I think the question is still wide open. What we really need is a study that follows animals forward throughout their lifetimes instead of using retrospective records or surveys to get the data – and, thanks to Morris Animal Foundation’s groundbreaking Golden Retriever Lifetime Study, we are getting just that. This study is enrolling Goldens as puppies and following their health over the course of their lives. It will be years before the study gives us answers, but it provides hope for more solid data. (Of course, it still can’t address the issue of bias, in that owners who enroll their puppies in this study could be highly responsible dog owners who provide excellent medical care!)

We can, however, do something about cancer in dogs without waiting for the results of that study. It is no coincidence that two of the studies discussed here investigated Golden Retrievers. Sixty percent of Golden Retrievers will die of cancer. That is indisputably a problem with the genetics of the breed, and other breeds suffer from similar problems. We should be attacking cancer on all fronts, and this is a front we don’t have to study first. Golden Retriever breeders are between a rock and a hard place, trying to breed for health in a gene pool which doesn’t have enough genetic diversity to support it. The solution is to bring in new blood from gene pools with much lower risk of cancer, breeding dogs who don’t look like purebred Goldens for a few generations to revitalize the breed as a whole. Genetics contribute far more to risk of cancer than whether an animal is spayed or neutered. We clearly have a strong desire as a society to reduce the incidence of cancer in Golden Retrievers and other breeds. While we’re studying risk from spaying and neutering, let’s address the genetics question that we know we can fix.


Image: Rob Kleine, Golden Retriever, Flickr Creative Commons License.

References

Torres de la Riva G, Hart BL, Farver TB, et al. Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers. PLoS ONE 2013. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055937

Zink MC, Farhoody P, Elser SE, et al. Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas. Journal of the American Veterinary Medical Association 2014;244:309–319. http://avmajournals.avma.org/doi/full/10.2460/javma.244.3.309 [Paywalled]

Hoffman JM, Creevy KE, Promislow DEL. Reproductive Capability Is Associated with Lifespan and Cause of Death in Companion Dogs. PLoS ONE 2013. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0061082
 

The history of dog breeds: Victorians, genetics, and the importance of diversity

Note: there is an interview with me at the Huffington Post about this story.

Dog breeds are amazing creations. I can own a series of Golden Retrievers and predict with fair accuracy how each of them will look and act. (Look more than act, but the incredible variety of dog personalities is a story for another day.) Unfortunately, I can also predict with fair accuracy what diseases each of those dogs will have, because with the Golden looks and personality come the Golden genetic disorders. As a new dog owner years ago, I thought of these genetic problems as part of the package I was handed when I got a purebred dog: you choose the looks and personality, and you choose the diseases at the same time. But there’s a lot more to the story of how dog breeds came to be saddled with particular genetic disorders than just happenstance: we made choices when we created breeds and we continue to make choices about their health today.

Figure from: Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication Nature, Vol. 464, No. 7290. (17 March 2010), pp. 898-902, doi:10.1038/nature08837 by Bridgett M. vonHoldt, John P. Pollinger, Kirk E. Lohmueller, et al.

The beginning of dog breeds
Humans have been breeding dogs for thousands of years, but for most of our history with them, function was more important than appearance. Dogs were bred to work, and beauty was a side effect: long coats were for keeping warm, small size was for chasing tunneling vermin, long legs were for speed.

During the Victorian era, things changed, with the spectacular growth of dog fancy. Suddenly people were breeding and showing dogs for how they looked, not how they worked. Breeds were no longer loose groups of dogs who looked kind of similar and did a particular job; now for the first time purebred dogs had carefully maintained pedigrees. This was the era when the breed books closed, meaning that breeds were suddenly defined as the set of dogs whose ancestors belonged to a select list. If you wanted to make more Golden Retrievers, you could only breed dogs descended from that original list. If you bred in dogs with unknown ancestry, their offspring were considered mutts and could not be competitively shown, even if they looked just like purebreds.

What happens when you take a relatively small set of dogs and use them to breed a much larger number of dogs? It’s like this small set of dogs is marooned on a desert island with no way to bring in new genetic diversity, and their pedigrees are what marooned them. Their descendants will look like them and act like them – and have their genetic diseases. The genetics from those few founders are all that's available to the descendants. When this reduced genetic diversity is severe, it can be a big problem.

Basenjis and Fanconi syndrome
Reduced genetic diversity is severe in the Basenji breed. This breed originated in Africa, but only the Basenjis descended from a small number of dogs imported to Europe in the 1930s are considered purebred. The diversity in this breed was so low in Basenjis in the Western world that in 1990, one in ten Basenjis suffered from exactly the same genetic disorder, a kidney disease called Fanconi syndrome. One or a few of the founding dogs must have had this disease, and it was passed on to their descendants until a large percentage of Basenjis suffered from it.

The solution: bring in new Basenjis from Africa, breed them to the Western Basenjis, and declare that their offspring may be considered purebred, despite a lack of pedigree.  This was done in 1990 and again in 2013, and the effects are still spreading through the Western Basenji population over several generations. (You can read about the trip to the Congo to acquire African Basenjis.)

Dalmatians and urinary tract stones
But what if there isn't an ancestral population waiting to be harvested? Dalmatians also suffer from a genetic kidney disease, in their case stones in their urinary tract caused by high levels of uric acid. It's a painful disease and there was no way to breed out of it: at one point, every single Dalmatian in existence had uric acid levels above normal canine values.

The solution? The Dalmatian Backcross Project, which began in 1973 with the breeding of a Dalmatian to a Pointer. The project husbanded along a line of Low Uric Acid (LUA) Dalmatians, also known as Normal Uric Acid Dalmatians, because what's low in a Dalmatian is normal in any other breed. Puppies from this original Dalmatian/Pointer cross were tested for uric acid levels, and those with normal levels were bred to purebred Dalmatians. This continued generation after generation until a line of Dalmatians had been bred which looked like Dalmatians, not Pointers, but had normal uric acid levels. As of 2011, LUA Dalmatians have been registered with the American Kennel Club and are now considered purebred Dalmatians. It remains to be seen how long the problem of high uric acid levels will remain common in this breed, but at least now there’s a solution in sight.

What we're doing about genetic health in dog breeds
With these success stories, you’d think the problem would be solved. But these are the only two breeds so far to open their breed books to bring in new genetic diversity. [ETA: readers note that a few other breeds have opened their books, including Border collies, Chinooks, Salukis, and Azawakh in the US, and several breeds in Europe. Fantastic!] Both the Dalmatian and the Basenji had easy to diagnose, easy to understand health problems that were also easy to identify with genetic testing: problems controlled by a single gene. Such diseases are relatively unusual. Take the case of the Golden Retriever, who is prone to developing cancer at greatly accelerated rates compared to most other breeds. Cancer is controlled by a lot of genes and is very hard to genetically test for – and therefore hard to breed away from.

While introducing new genetics into Golden Retrievers is very likely to improve the health of the breed, it’s hard to convince breeders to take the leap. As was the case with the Dalmatian Backcross Project, such an undertaking would mean producing dogs that didn't look like Goldens for a few generations. They could still make great pets, but they couldn’t be shown and they probably couldn't be sold for as much money as a purebred. And there’s no guarantee that their descendants could ever be registered as purebreds – the fight to get LUA Dalmatians accepted was long and hard. I use Goldens as an example because I live with one, but many of the breeds we love suffer from low genetic diversity and associated genetic health concerns.

I believe we need as a society to get past our obsession with historical breeds. We can breed for appearance, but that has to take a back seat to breeding for health. We have a model with the Dalmatian Backcross Project. All we need is the will to improve the genetic health of more breeds.

Jack the Pumpkin King, my 14 year old Golden Retriever. He has so far only developed a small tumor, which was easily removed. However, he suffers from skin allergies and epilepsy, both genetic disorders.

What breed is my shelter dog?

I am weekly asked the question “so what kinds of dogs do you have?” People don’t ask this about cats. But it is the first question they ask about a dog. We use a dog’s breed as shorthand to tell us the dog’s size, color, build, and to make predictions about its temperament and energy level.

I usually describe my dogs as a “golden” (one word) and a “32 pound something or other, probably a border collie/retriever mix“ (11 words, and I didn’t even get her color in there). Some dogs, like my golden, can easily be pointed to and called a purebred, even if they aren’t registered (which is the technical definition of a purebred). But once you start mixing purebreds, it rapidly becomes surprisingly difficult to predict the heritage of the puppies. Traits that you think of as the defining characteristic of a particular breed, like that rich golden color, are often recessive and disappear in the first generation of mixed breed puppies. Look at pictures of puppies of known mixed breed heritage and you’ll be surprised again and again at how impossible it is to guess the parents’ breeds.

Now, I do make guesses about breed heritage when I describe my little mutt. But is she really a mix of breeds? Is it possible that there are a lot of dogs out there that owe more of their heritage to a pool of dogs that never got sucked into the closed breeding groups of registered breeds, and were always just something or others?

So why do I persist in making up breeds for her? Because it is shorthand. People understand it. It gives them a handle to use in building their imaginary picture of this dog I’m describing: her general size and shape and, of course, temperament. Of course, what a dog looks like does not predict very much about its temperament (except maybe that little dogs often have Napolean complexes — and that is nurture, not nature!).

As for the rest of it, we don’t have to say that a dog is a breed. We can say that it is a type. This is really what we are doing in a shelter when we guess the breed of a dog to write on its adoption card. No one really thinks that all those “lab mixes” definitely have Labrador Retriever in them, but it lets potential adopters browsing on the internet to know what to expect and to make a decision about whether to come in to the shelter meet the dog.

So what is my little mutt? Maybe next time I will say she is a “collie type” dog. As for the rest of it, describing her exact color and personality always makes for a fun conversation.

Land of eyeballs: ophthalmology rotation

I was really surprised at how interesting I found my ophthalmology rotation. Two weeks of eyeballs should have been mostly boring and creepy, right? But it turned out to be rife with my favorite kind of veterinary ethical issue: how we breed dogs.

Take the several bulldogs we saw who had so many facial wrinkles that their skin was folded over their eyes and rubbed against their eyeballs. (They also had yeast infections in the depths of their wrinkles, but that was a problem for a different department.) These dogs required surgical intervention to cut off the worst of the wrinkles. If they did not receive the surgery, they would be extremely uncomfortable (they all came in with red, squinty eyes), and would eventually get corneal ulcers which would proceed to infections and possible removal of the eye in question.

We also saw a raft of brachycephalic (flat-faced) dogs whose faces were so flattened that their eyes bulged out. Some of them could not completely close their eyelids. Their eyes were at risk for damage just due to being so out there in the world and unprotected. In the opinion of the ophthalmologists, pug owners all need to be given special eye care instructions when they acquire their new dog.

I asked the owner of one of the dogs that required surgery about where he had gotten the dog. He replied that the dog came from a breeder. I suggested that he get in touch with the breeder to let her know about the necessary surgery, so that she could use that information to help her choose wisely which dogs to breed in the future, and try to avoid producing more puppies with the problem. He replied in surprise, “I thought this was just a breed-related problem.”

Yes, these are breed-related problems. But breed-related isn’t synonymous with inevitable. It doesn’t mean we can’t try to avoid them as we create more dogs of that breed. Veterinarians can and should be more clear with their clients about this. They don’t have to be confrontational to do it! They don’t have to imply that the client made a mistake by purchasing the dog. They can instead look to the future: here’s what we can do to make the breed better.

The ethics of dog breeding: to breed or not to breed?

It’s challenging to breed purebred dogs well. You have to balance appearance, health, and temperament, and of course by “health” I actually mean “2598237 different possible inherited diseases.” You breed or buy the best animal you can (no small task in itself), you compete with it to prove its ability and conformance to the breed standard, and then when it is an adult the time comes to breed it. Before you breed, you have to make sure the animal is physically healthy. You perform perhaps thousands of dollars worth of tests towards this goal. If your star fails any one of them, you should consider not breeding it, even if it is otherwise a great breeding prospect. If it fails a really important test — like the assessment of the likelihood of developing hip dysplasia in a breed that is notorious for its hip problems, like the golden retriever — then you really shouldn’t breed the animal.

Time was, dog breeders had big kennels, with dozens of dogs. If one of them turned out to have an inheritable health problem, it was fairly easy to just remove that animal from the breeding program. After all, if you have 50 dogs and can only breed 49 of them, what’s the big deal? These days, people have less land, and dog breeders tend to have smaller numbers of dogs. So what happens if you are the owner of a single, beloved pet and you really want to try to improve the breed by having a litter from this pet? You show, you compete, you have health tests, and the animal fails the test for healthy hips. Now it’s not just a question of not breeding a single animal. Instead, it’s a question of not being able to breed at all, unless you get another dog and start over. What if that one has a health problem too, and you really don’t want to have three dogs in your house?

It’s a tangled issue. Personally, I think dogs do better in homes than in kennels, generally speaking (although I recognize that there are some private kennels out there containing some very happy dogs). But I also think that if we are going to be selecting dogs for beauty, as we do with show dogs, we have a responsibility to not let health fall by the wayside. Making the breeding of healthy dogs easier is a good thing. It’s sad to think that the fact that more dogs are living inside as pets makes breeding responsibly more difficult.

The art of dog breeding: Puppy has two daddies

Not just every puppy has two daddies. How would it happen?

It’s a long story, so stick with me. Let’s say you’re deeply involved in the dog world, and love a particular breed of dog. You breed to improve that breed. You have a young bitch that you are considering breeding. You start out by taking this bitch to dog shows, doing that circuit until the bitch has earned her championship after a number of wins at different shows. This shows that the bitch is conformationally excellent enough to be worth breeding. You may also work with the bitch in some other area, like competition obedience, tracking, or agility.

When the time comes to breed, there is more work to do. You have to make sure the bitch is genetically good material. You know what problems are common in the breed, so you test for those. There are some problems (like hip dysplasia) which are so common that breeders test for them in almost every breed; there are some that are more rare. Some tests are genetic tests done on DNA samples. Some are just the sorts of tests any vet might do to see if the levels of different chemicals in the blood are within normal ranges, or if they are suggestive of certain conditions. All these tests have to be done on both sire and dam.

Who’s the sire? You should pick out a sire that complements this bitch well. No animal is perfect. If the bitch’s biggest failing is her less than perfect hip conformation, then the sire should have really exceptional hip conformation, to balance that problem out. They should not be too closely related, either.

The right sire may live across the country or across the world from the bitch. If he’s far away, artificial insemination will be necessary (although some animals get transported quite a distance for sexual liaisons, and some bitches are artificially inseminated even though the dog is in the next room). When exactly should this occur? If the dog is prime breeding material, his semen will be very expensive, not to mention the fees for implanting it (more on that later). So you want to do it as few times as possible.

It’s also important to know as precisely as possible when the bitch ovulated, because this helps predict when she will give birth. So ovulation prediction is an important part of this process. It involves blood tests over multiple days, done by a veterinarian.

Once you know what the bitch’s three fertile days will be, how will you get the semen in? You can choose natural service (the old fashioned method), artificial insemination into the vagina, or intra-uterine insemination (surgical insemination directly into the uterus). This last approach is the most reliable, although of course it is also the most invasive and expensive.

If you don’t choose natural service, you may be getting either fresh semen (from the dog in the next room), fresh chilled and shipped overnight (from somewhere on your continent, collected the previous day), or frozen (from anywhere in the world, and possibly as venerable as twenty years old). Why would you artificially inseminate fresh semen, if the dog is right there? Some bitches can be cranky if they don’t approve of the dog on offer, and there can be violence. The owner of an expensive (or well loved!) stud dog might not wish to risk his injury.

Now it comes down to it. Many breeders will have spent thousands of dollars to get to this point. Some will have spent tens of thousands. They really, really want to have a successful impregnation. The fresher the semen, the more reliable it is. If the best possible sire is only providing frozen semen for whatever reason, the chances are significant that the bitch will not get knocked up. So what do you do?

On the bitch’s first fertile day, you use the frozen semen from the preferred sire. You hope that all her eggs get fertilized by this semen, but if some are left over, you call in the backup sire, someone local who can provide fresh semen. Hopefully any eggs that failed to get fertilized by the first sire will get handled by the second. You may well end up with puppies from each sire in the litter, but that’s fine; you can DNA test them to know who’s sired by whom. And that is how a puppy can have two daddies, or, at least, a litter can.

(Note: I skipped over the numerous ethical issues brought up in this story. For today, I just wanted to share with you some of the surprising tools available to dog breeders today.)

The Purebred Paradox, part four: What can be done?

(Continued from part three.)

Below are my musings on some of the talks at the recent conference, The Purebred Paradox: on the health and welfare of purebred dogs. Specifically, these talks delve deeper into ways some of the speakers thought we could move forward.

Professor Sir Patrick Bateson: “Problems of dog-breeding and what to do about them”

In his keynote address, Professor Bateson called for for “a public awareness and education campaign.” In his talk and in later discussions, the question of whom to educate was raised. Three interest groups were identified: dog owners, dog breeders, and judges of dog conformation competitions. Again and again, speakers at the conference returned with frustration to the question of how to educate dog owners. Once the bulldog has been purchased and the new puppy brought to the veterinarian for its wellness exam, it is too late. How do you educate people about healthy breeds before they bring home and bond with a new dog?

Patricia Haines, DVM: “Canine Genetics, Behavior and the role of the parent club”

Dr. Haines, a veterinarian and breeder of pointers, talked about parent breed clubs. Both the American Kennel Club (the AKC, the largest registering body of American purebred dogs) and the Kennel Club (the KC, the AKC’s British counterpart) are made up not of direct members but of member clubs, or “parent clubs.” These clubs mostly (but not entirely) represent breed specific clubs, such as the Golden Retriever Club of America.

Dr. Haines made the point that work for change would be more effective with the parent breed clubs, rather than with AKC judges. In fact, she said, many breeders joke that the judges don’t really know their breed well. It is the parent clubs which are the guardians of the breed standards, and, perhaps more importantly, the interpreters of them.

Dr. Haines’ insight highlighted, in my opinion, the usefulness of working with members of the dog breeding community. That community is a complex one which can be difficult to fully understand from the outside.
 
Gail K. Smith, VMD, PhD: “Efficacy of hip dysplasia screening: An animal welfare imperative”

Dr. Smith is the veterinary surgeon who designed the PennHip screening system for hip dysplasia. The more traditional Orthopedic Foundation for Animals screening system involves subjective judgement of a dog’s hips as poor, fair, good, or excellent. PennHip, on the other hand, provides an objectively determined “distraction index,” a numerical measurement of the amount of hip laxity (where more laxity implies worse disease). Dr. Smith explained that his PennHip system is particularly useful for genetic studies of hip dysplasia because it is a better measurement of phenotype, for use in correlation to genotype. In other words, if you want to study what genes produce hip dysplasia, an objective numerical value describing the individual animal’s anatomy is more useful than a subjective value like “fair.”

Of course, the question arises: can other characteristics be measured using numerical scales? How do you measure the flatness of a bulldog’s face? There is work to be done in this area.

Steve Zawistowski, PhD, CAAB: closing remarks
PhD behaviorist Dr. Sawistowski explicitly identified a fissure between those who breed dogs and those who identify themselves as members of animal welfare organizations. He said, “We are going to have to heal that fissure before we can heal the dogs that we all know and love.” This conference did a great job of outlining this goal and the current situation and identifying priorities to be addressed.

The Purebred Paradox, part three: Analyses of the situation

(Continued from part two.)

Below are my musings on some of the talks at last week’s conference, The Purebred Paradox: on the health and welfare of purebred dogs. Specifically, these talks delve deeper into what some of the current health risks are for purebred dogs, and why.

Brenda Bonnett, BSc, DVM, PhD: “Breed risks for disease in purebred dogs”

Dr. Bonnett is an epidemiologist who worked with “12 years of [health] data from over 200,000 dogs yearly,” obtained form Agria Pet Insurance in Sweden. Her talk was fascinating; placed as the very first presentation, it was a great introduction to the conference. She showed a series of graphs comparing the risk of different diseases in different breeds. Using the pet health insurance data, she could identify some risks as part of the risk of “being a dog” (diseases equally likely to occur in any breed) versus the risk of, for example, “being a German shepherd” (hip dysplasia, much more likely to occur in that breed than in most others). These graphs made the case very clearly that many breeds have risks of particular diseases.

The graphs were also an excellent way of demonstrating which diseases should be prioritized in particular breeds. She talked specifically about Cavalier King Charles spaniels, a breed which is prone to a particularly painful brain disorder called syringomyelia. Syringomyelia in CKCS was publicized in Pedigree Dogs Exposed and has been receiving a great deal of attention as a result. But her data suggested that another breed problem, heart disease, is much more prevalent. Syringomyelia, a disease in which your brain is squeezed out of your skull because your head is too small, is certainly very sexy, but if a CKCS is much more likely to die of heart disease, perhaps the issue of the heart disease should be addressed first.

But we already knew that different breeds get different diseases, right? When you are picking the breed of your next puppy, if you’re doing your research, part of your decision is whether you can deal with the risks of that particular breed. Is it more likely to get hip dysplasia? Heart disease? Cancer? Dr. Bonnett made the point that people will accept some types of risk, and some levels of risk, but not others. Life has some risks that you can't avoid; playing with sticks can be risky for a dog (GI obstruction! cracked teeth! splinters migrating into the sinuses!) but people accept those risks because they are part of being a dog. However, owners also accept the risks which are part of being a particular breed. Should they?

Dr. Bonnett concluded her talk by telling the story of a Bernese Mountain Dog (berner) owner who had come up to her after a previous talk. This woman had said that she had known that berners suffered from an increased rate of cancer, but had had no idea quite how bad the situation was until she listened to Dr. Bonnett’s presentation. However, this woman said, she would keep owning berners, because they were her breed. One of the themes of the conference was certainly the deep loyalty people have to “their” breed. (I completely understand it, as I feel that way about golden retrievers.)

Ilana Reisner, DVM, PhD, DACVB: “Unintended consequences of breeding for conformation: Owner-directed aggression in English Springer Spaniels”

Dr. Reisner is a veterinary behaviorist who presented a case study of an owner-agressive English Springer spaniel. This breed is particularly known for what has been called “springer rage,” sudden fits of aggression to the owner. The subject of Dr. Reisner’s presentation, Pluto, had bitten every member of the household, including the 80 year old grandmother. Dr. Reisner joked, “It wasn't too bad, just a few amputations.” She made the point that, while the conference was focused on dog welfare, when people live with dogs who are suffering or who have behavior problems, human welfare is also affected.

Frances O. Smith, DVM, PhD: “The development of dog breeds: Why and how people breed dogs”

Dr. Smith was a veterinarian, Labrador retriever breeder, dog show judge, and theriogenologist. (A theriogenologist is a veterinary specialist who has advanced training and board certification in breeding and reproductive problems.) She was clearly an exemplary breeder. She talked about the best dog she ever bred, who was a conformation champion and a performance champion. Dr. Smith emphasized again the importance of breed specific traits in the hearts of owners and breeders. The breeds must stay unique and recognizable. Any other solution to the problem is going to be very hard for many dog lovers to accept.

Dr. Smith seemed to have been asked to speak as a representative of the breeder side of the debate. I wish that we could have heard from some breeders at the show who were not cherry-picked to be non-controversial, however. The Labrador is a sporting breed, and sporting dogs tend not to suffer from breeding for extreme characteristics, as they are often expected to still be able to do work. (To understand what is meant by “extreme characteristics,” enjoy this post by the producer of Pedigree Dogs Exposed about the Neapolitan mastiff.)

Frank McMillan, DVM, DACVIM: “The impact of puppy mills on the welfare of purebred dogs”

Dr. McMillan is an internal medicine specialist and employee of Best Friends animal shelter in Utah. He talked about the widely publicized problem of puppy mills (high-volume, commercial breeders, who I’d argue are irresponsible by definition). He showed a number of disturbing photos of adult breeding animals taken from filthy and unhealthy circumstances at various mills.

Dr. McMillan’s main point was that the psychological damage done by lack of socialization to adult breeding animals in high volume breeding facilities is severe and should not be overlooked. Even dogs maintained at sparkling clean facilities are not given the socialization time they need as puppies to function properly once they are taken out of the puppy mill as adults. He read accounts and showed photos of these adult rescues, and demonstrated their complete inability to bond with their new owners after months, some even unable to be housebroken as they could not be approached with a leash to be taken outside. He argued convincingly that many of these dogs should be considered victims of post-traumatic stress disorder. No amount of regulation or oversight by the USDA will change this fundamental lack of socialization of dogs kept in situations where they do not get a chance to experience the world outside of their kennel.

(To be continued.)

The Purebred Paradox, part two: What’s the problem?

(Continued from part one.)

I recently attended The Purebred Paradox: on the health and welfare of purebred dogs. These are my musings on a few of the talks at the conference, specifically those detailing what exactly the problem is with current methods of dog breeding.

David Sargan, PhD:  “The RSPCA report on purebred dog breeding: Conformational selection and inbreeding in dog breeds”

David Sargan summarized the 2008 RSPCA report on purebred dog breeding. Before the release of the Pedigree Dogs Exposed documentary, the RSPCA had not really focused on issues in purebred dog breeding. This report represents their initial attempt to grapple with how they were going to address these issues.

The report identifies two welfare issues: exaggerated anatomical features that reduce quality of life, and an increased prevalence of inherited disorders. It also discusses current screening practices. Standardized screening is available for eye and hip disorders, among others. These screens are used only by a self-selecting population, however, so are not useful for a description of the true prevalence of a particular disorder in the population. For example, dogs which are not intended to be bred — “pet quality” dogs — are less likely to be screened, though they may well have a genetic disorder. Dogs with unsubtle signs of disease may also not be screened, but simply treated. DNA tests are being developed for many diseases, but many diseases exist for which no DNA test has yet been developed. Of course, many diseases do not lend themselves to DNA tests, as they may be multifactorial in origin, due to many different genes, or to interactions between genetics and environment.

The report outlines possible ways forward. Among its many recommendations are more systematic data collection; an increase in genetic diversity, both by limiting inbreeding and by opening the kennel club stud books (allowing offspring of unregistered dogs to be registered as purebreds); and work to improve the screening tests available.

The report concludes: “the most important element is to ensure that all stakeholder groups buy into the process and fully support the action(s) they need to take. This is the challenge that lies ahead.”

Jemima Harrison: “Pedigree Dogs Exposed: The Aftermath”

The producer of the hugely influential Pedigree Dogs Exposed spoke on the aftermath of the film. Actually, she started by outlining the premath, noting that change has been called for in pedigree dog breeding for over 100 years, and including newspaper stories and other references. She wondered if her film had caused enough change to really get and keep the ball rolling — has the sea change happened? Or is there more work to do?

She wasn’t sure, but she did include a video of Fiona, “the first mongrel to be shown at Crufts.” Fiona is the first low uric acid Dalmation to be shown at the number one UK dog show. The LUA Dalmations are the product of a single outcross to a pointer, and subsequent selective breeding to remove the gene for a genetic predisposition to kidney stones whch is present in every Dalmation except for those with this pointer heritage.

(Continued in part three.)

The Purebred Paradox, part one: Background

In 2008, the BBC aired Pedigree Dogs Exposed, a documentary about breeding practices in purebred dogs. The documentary suggested that health problems are on the increase in purebred dogs, and that many of them are avoidable. Specifically, some problems are due to limited gene pools and unintentional fixing of traits such as predisposition to cancer; others are due to intentional breeding for extreme characteristics like flat faces or heavily wrinkled skin. This documentary triggered a strong reaction from the public, and the beginnings of some changes in how members of the UK breed clubs approach breeding dogs.

It also triggered a negative reaction from the British Kennel Club, and a great deal of controversy. The two sides of the debate are, in my own words:

• Dog breeds are part of our heritage and are important to us. Each breed has its defining characteristics (the unique color of the golden retriever’s coat, the size and shape of the Great Dane, the jowly face of the English bulldog). These characteristics are what make each breed unique, and should be celebrated and maintained. I’ll call the people on this side of the debate the dog breeders, at risk of a gross overgeneralization.
• The health of many purebred dogs is endangered both by consequences of inbreeding (such as overrepresentation of genes for cancer in Bernese Mountain dogs) or by breeding for extreme traits (such as the extremely flat face of the pug). We should start prioritizing the health of our purebred dogs over maintenance of breed purity. I’ll call the people on this side of the debate the advocates for change, although many dog breeders take this viewpoint as well.

Last week, I was privileged to attend a conference in Washington, D.C., called The Purebred Paradox: on the health and welfare of purebred dogs. This conference was intended to move the debate, which had begun in the UK, to this side of the ocean. By my estimates, however, more than a quarter of the speakers and attendees hailed from overseas.

One of the unstated goals of the conference seemed to be to get the two sides, breeders and advocates for change, to start a real discussion. In my opinion, the discussion was hampered from the start by the fact that the conference was not organized by breeders, and was by no means neutral ground. Representatives from the breeder camp were underrepresented, and seemed as well to have been selected to be not too controversial. Everyone was very civil, but I didn't feel like anyone’s mind was really changed.

That didn’t stop me from having two of the most enjoyable days I’ve spent in months or even years. About half of the speakers were veterinarians, and vets were very well represented at the conference overall, which surprised me. It has been my observation in veterinary school that veterinarians are as a general rule not greatly worked up by breeding practices — it’s part of the profession’s usual refusal to judge the husbandry decisions of an animal’s owner in public unless truly abusive. Apparently some vets are coming to see some breeding practices as crossing that line into abuse, and are interested in seeing change.

It shouldn’t need saying, but I will say it, just to be super clear: I have nothing against breeding purebred dogs in theory, and there are quite a few extremely responsible, ethical breeders out there — I met a lot of them at this conference. But there are breeders who do seem to be blind to the discomfort that breeding for extreme characteristics can cause dogs, and there are some breeds that I believe cannot be humanely bred under current practices, though could certainly be humanely bred with some conservative modifications to the breed standard (or to interpretations of it). I am not anti-breeder, but I am very much against certain breeding practices.

(To be continued.)