Thursday, March 19, 2009

ABC's NIGHTLINE: Best of Breed? Pedigree Dogs Face Disease

It's pretty obvious that Nightline didn't bother to sniff out any legitimate sources of information when "researching" the feature piece Best of Breed? Pedigree Dog Face Disease.

First of all, why were there no interviews with people having real credentials in Canine Genetics?

(1) Jemima Harrison claims she did two years of "research" much of which apparently involved reading a Canine Genetics email list online. Just imagine if a layperson decided to follow an email list intended for doctors for two years, would anyone want to be medically treated by that person? Of course not! Jemima Harrison is not formerly trained in genetics, she is not working in an area of genetics, she is not a dog breeder, and she is not a veterinarian. She has basically just taken some one-sided opinions expressed on an email list, found a handful of like-minded people, and a few sick purebred dogs (which may or may not have been bred by show breeders) and put them all on film.

(2) Terrierman lurks on the same Canine Genetics email list and also harvests information of interest which he then puts on his blog in a one sided way. He censures all comments to his blog and will not post any remarks that are contrary to his own. Terrierman called Caroline Kisko, Secretary of The Kennel Club (UK), a liar on his blog and then he ridiculed and twisted her response in a follow-up blog. He has also publically poked fun at overweight dog show exhibitors. Is this the behavior of a credible authority on purebred dog breeding? A review of the "voracious" blogging reveals a great deal of vulgar and bigoted content and there is not a single dissenting comment to be found. Of course not, afterall, Terrierman doesn't publish any comment contrary to the not-original-from-him blog entries. Censureship is also an ideal way to prevent disgruntled comments appearing on the blog from folk unhappy about having their ideas plagerized. Hmmm, no credentials in genetics or veterinary medicine, no actual involvement with breeding show dogs, and merely parroting the ideas of others that he has read on canine genetics lists. Does blogging the stolen ideas of others make a person an expert? Just why did Nightline interview him?

(3) Dr. Serpell B.Sc. (Zoology) Ph.D. is the Director of the Center for the Interaction of Animals and Society. The Center for the Interaction of Animals and Society focuses on the behavior and welfare of companion animals; development of human attitudes to animals; history of human-animal interactions; measurement of behavioral phenotypes in dogs and cats; ontogenesis of behavioral problems in companion and working dogs; and animal-assisted therapeutic interventions. I am sure Dr. Serpell is super great at his job but he is NOT a geneticist.

Inbreeding and Linebreeding

Dr. Serpell stated "if they didn't do all this inbreeding and line-breeding to begin with, there wouldn't be all these genetic problems". This statement minimizes the complexities of breeding and inheritance. Defective genes date back to prehistoric times. Inbreeding and linebreeding DO NOT create defective genes but they can help to bring the existence of defective genes quickly to the surface, thereby alerting a breeder to the possibility that a particular problem may be genetic in nature. There is an advantage to being aware of potential genetic problems, breeders can then take steps to breed away from the problem and remove the defective gene(s) from the line or population. DNA tests can help in this respect as well.

Inbreeding (very close breedings of parent to offspring or littermate to littermate) is actually extremely rare in the breeding of dogs and comprises less than 1% of all dogs registered with kennel clubs. So all this fuss on Pedigree Dogs Exposed, Terrierman's Blog, and Nightline over a tiny fraction of the purebred dog population! Both programs compared dog breeding to the practise of eugenics and incest.

I love my dogs but at the same time I realize that dogs are not the equals of human beings. Selective breeding of dogs is in no way similar to the ethical considerations involved with the practise of eugenics with human beings in the past.

Nor are inbred puppies comparable to children resulting from an incestuous relationship. There are moral and ethical issues with regard to human incestuous relationships that do not apply to dogs.

There are examples of children resulting from human incestuous relationships who have genetic disorders, but there is a huge difference between inbreeding/ linebreeding dogs and the intermarriage of closely related communities and/or incestuous relationships.

The difference is the use of selection which is acceptable in the breeding of animals, but morally reprehensible to human beings, harkening back to the dark days of eugenics. Selecting for health, temperament, structure, and appearance in dogs is intended to improve and preserve health and breed characteristics.

Used appropriately, careful selection for positive and useful attributes can be beneficial in the breeding of dogs (although those who consider dogs to be "children in fur", with the same rights as human beings, will probably never agree).

The occasional use of inbreeding is not going to create unhealthy dogs unless both parents carry for the same defective recessive genes or one parent passes on an unexpressed defective dominant gene (one having incomplete penetrance). The same would be true of a breeding of two mixed breed dogs if they both carried for the same defective genes, or if one parent carried an unexpressed defective dominant gene. The same applies for line-breeding and outcrossing. It's not the breeding method that is used that matters, it is whether the two dogs that are being bred carry the same defective genes or one carries for an unexpressed dominant gene. It's about gene combinations and gene expression not breeding methods.*

[*Please note: The above paragraph assumes that unaffacted carriers are being used. There is a very important difference between unaffected carriers and affected carriers. While both are carriers of defective genes and can pass them on, unaffected carriers never develop the genetic disorder, whereas affected carriers are obviously affected by the genetic disorder. Affected carriers are not normally used in breeding programs except under the most exceptional of circumstances, taking into consideration the severity of the disorder. Unaffected carriers can be bred to dogs free of the defective gene and never produce the genetic disorder. The same is not true for affected carriers.]

Some will try to convince you that inbreeding and line-breeding increase the probability of genetic defects "on average" within a population, but there is nothing average about purebred dog populations. Show breeders comprise about 20% of all the purebred dogs that are registered (AKC June 2007 Delegate's report: "today only about 20% of dog registrations originate from the Fancy"), the other estimated 80% come from commercial breeders, and puppy mills, backyard/one-time/accidental breeders. All of these groups and the individuals within these groups are NOT all equally concerned about producing healthy dogs.

Pedigree Dogs Face Disease?

Show breeders are highly concerned with producing healthy puppies for themselves and puppy buyers. A dog cannot be successful as a show dog if it does not appear healthy, well-structured, and well conditioned. Show breeders, for the most part, make use of screening tests to check for hip dysplasia, eye problems, blood disorders, heart problems, etc.

This same claim cannot be made for the others who are producing the estimated 80% of purebred dogs that are registered.

When looking at purebred populations as a whole, the lack of testing by the breeders producing 80% of registered dogs pretty much wipes out the positive efforts of the 20% who do try to breed for healthy dogs. So much for those average probabilities someone tried to convince you about.

What is needed are health studies of each of the subgroups within breeds and comparisons between the subgroups and then each subgroup with other breeds. Meaningful findings CANNOT be gleaned from breed averages calculated from unrepresentative samples - that's just basic knowledge to anyone with a background in statistics.

Purebred dogs are also further segmented by purpose. Some breeders breed just for pets for the pet buying public, others for show and pet buyers, others for work/function (and presumably for pet buyers looking for high drive puppies), others breed for dogs capable of show and work/function, and some purebred dogs are just unwanted accidents that were not bred for any purpose at all.

What matters is not what the dog is bred for but how healthy the dog is. Dr. Jerrold Bell DVM, Tufts University School of Veterinary Medicine recommends using healthy dogs for breeding. Healthy dogs tend to produce healthy offspring. He has written numerous articles for dog breeders, many of which can be found online and in dog-related publications. Why was Dr. Bell not interviewed for this piece?

Where Was the Input From Recognized Authorities on Canine Genetics and Dog Breeding?

Glaring omissions in both Nightline's Best of Breed footage and Pedigree Dogs Exposed:

No input from Geneticist Dr. Malcolm B. Willis B. Sc. PhD., Animal Breeding and Genetics, Faculty of Agriculture and Biological Sciences, The University, Newcastle upon Tyne, who is the author of the book, The Genetics of the Dog, and numerous papers that can be found online and in dog publications including The basic tool kit for responsible breeders and Inbreeding and Pedigree Dog Breeds.

No input from Dr. Jerrold Bell DVM, Tufts University School of Veterinary Medicine, who has spoken to breeders at many conferences and who has written numerous papers on genetics and dog breeding which can be found online and in dog publications including Pedigree Analysis, and How Breeding Decisions Affect Genes.

No mention of the late Dr. George A. Padgett DVM , who was a professor, veterinary pathologist, author of the book, Control of Canine Genetic Diseases, and founder of the Genetic Disease Control Institute.

No mention of the Orthopedic Foundation for Animals (OFA)) which has been reading xrays and recording orthopedic reports for dogs for over 40 years. OFA has recently expanded to maintaining records for other health matters beyond orthopedics and many of the databases founded by Dr. Padgett and purebred dog clubs have been incorporated into the OFA online database.

No mention of the The Canine Health Information Center (CHIC) which in conjunction with OFA encourages breeders to perform essential breed specific health tests and also allows breeders to store DNA samples of their dogs for DNA research purposes.

The way of the future is open canine health databases and DNA tests. More information on both can be found at Genetic Disease Control Institute and from A. N. Meyer-Wallen's Ethics and genetic selection in purebred dogs.

All Doom and Gloom?
There was not a single solution generated in the highly sensationalized footage of Nightline's Best of Breed or BBC's Pedigree Dog's Exposed, nor did either focus on the collective efforts of dog breeders, purebred dog clubs, veterinary researchers, and the OFA to improve the genetic health of dogs.

Dr. Serpell condemned with faint praise when he said "to be fair to the kennel club, they are doing quite a lot to try and fix the problems that are there, but for me that's a bit like closing the gate after the horse has bolted". If he was really being fair he would have noted that DNA research and the development of DNA tests to screen for defective genes has only been around for about 20 years and to date there have only been a limited number of DNA tests developed.

However, while only a small number of DNA tests have been developed so far, breeders have made very good use of the ones that are currently available. One example is the DNA test for PRA in Irish Setters which was developed in 1995. Between the new DNA test and the test-mating programs breeders had been using before the test, PRA has been virtually eliminated in the breed worldwide. The Irish Setter Genetic Registry for PRA clear Irish Setters was recently merged into the OFA online database.

Research is ongoing into many of the genetic disease which can be found in (all) dogs, and in time more and more tests are likely to become available. We are basically on the cusp of a genetic revolution in dogs. The record keeping capacity is in place (OFA) and the recording of the results of the screening tests that are currently available continues. Most breeders anxiously await the development of more DNA tests to help them identify carriers of genetic diseases in their respective breeds. No, Dr. Serpell, the horse has not bolted, we are only at the beginning stages of being able to use DNA information to avoid producing genetic disorders. All is not lost, in fact the gate-way is wide open.

Nightline, you got this wrong too!

A statement made in the Nightline program that was incorrect is that "breeders are supposed to stop breeding dogs that carry genetic mutations". Nothing could be further from the truth. From a genetic diversity perspective, dog breeders would not want to eliminate all carriers from the gene pool of a breed.

Carriers of defective recessive genes (once identified through DNA testing) can be safely and responsibly bred to a dog that has been shown through DNA testing to not carry the defective gene. Carefully breeding unaffected carrier dog to clear dog will NEVER EVER produce a dog with that particular genetic disorder (please refer to earlier note concerning unaffacted and affected carriers) .

Finally, Dr. Serpell recommends cross-breeding to "fix" purebred dogs. Currently, purebred breeds have health issues which tend to be unique to the breed, not the myriad of problems that are found in the mixed breed population. It's a lot easier to deal with a few problems than many, and DNA tests are going to come in fast and furious in the next decade or so, and purebred dog breeders will be able to work around many of the problems that affect their respective breeds. Structural problems can be dealt with within breed populations by breeding to individuals that have the desired structural feature. There is no need to cross-breed in order to make corrections to most breeds of purebred dogs (unless the problem absolutely cannot be solved within the breed*) and in fact doing so will likely bring in other genetic problems previously unknown to that particular breed.

[*Please note: Some believe the Dalmatian breeders need to resort to cross-breeding to address the breed's tendency to high uric acid levels. According to the Dalmatian Club of America "Dalmatians, humans and apes are unique for the way in which they metabolize "purine-yielding foods." Not every human will form urinary stones and neither will every Dalmatian". Urine concentration appears to be a key factor in whether or not a Dalmatian will develop bladder stones and good management and unlimited access of water can prevent stone formation. There are some strong advocates for using the progeny of a cross-breeding of a Pointer and Dalmatian to introduce the normal gene into the Dalmatian population. These back-crossed dogs do not have the mutation in the SLC2A9 gene which is responsible for the elevated uric acid in the Dalmatians. The Dalmatian community has chosen not to include the progeny of the cross-breeding in the American Kennel Club (AKC) registry (though they can be registered with the United Kennel Club (UKC)). Now that the gene that causes the high uric acid excretion in Dalmatians has been discovered there is hope that high-tech gene splicing will eventually be able to introduce the normal SLC2A9 gene without resorting to crossbreeding and the risk of introducing health problems known in Pointers but not in Dalmatians.]

But mixed breeds are healthier than purebreds, right?

It is a myth that mixed breed dogs are healthier than purebred dogs:

Mixed breeds also carry defective genes and can develop genetic disorders.

Cross-breeding two purebreds can lead to the introduction of previously unknown problems for both breeds.

Designer (hybrid) dogs can be affected with genetic disorders.

Mixed breeds and hybrid "designer" dogs (mixed breeds with a disceptively fancy name) are NOT healthier than purebreds as veterinarian Pete Wedderburn points out in 101 Variations Part 1 and 101 Variations Part 2, as does Naomi Kane in Oodles of Doodles.

The one critical difference between healthy and unhealthy dogs is whether both parents carried for the same recessive defective genes and passed both to their offspring or one parent passed on a dominant defective gene.

All dogs and humans carry between 2 -5 lethal genes. Every population for every species on earth carry defective genes and always have. This is not unique to purebred dogs.

Single copies of recessive defective genes and unexpressed dominant genes never cause a problem unless the dog or person happens to have offspring with another carrier of the same defective gene or passes on the dominant gene which is expressed in the offspring. It's all about the combination and expression of genes.

While there are no studies available on the overall health of purebred dogs, it is estimated that 90% of purebred dogs are generally healthy and happy companions for their owners, although some may have minor issues. There are literally millions of purebred dogs in this world and if they were all sick, common-sense says there would not be enough veterinarians to care for them all. In general veterinarians see mostly dogs and other pets that have health problems. Healthy dogs are less likely to figure in veterinary clinic statistical studies because there is no need for them to be seen by a veterinarian, especially now that annual vaccinations are no longer recommended.

How can I increase my chances of finding a healthy purebred puppy?

Puppy buyers who are worried about getting a healthy puppy should contact national breed clubs to get leads to breeders who have signed statements to abide by the breed club's code of ethics.

Ask about the registered names of the dogs that are being bred and look them up on the OFA database ( to confirm that they have been cleared for certain basic testable health issues.

This is not an absolute guarantee that you will get a healthy puppy, because there are many genetic conditions for which health tests have not yet been developed, however confirming that the parents of the puppy have had some basic health screening does indicate that the breeder is concerned about producing healthy puppies and is making use of the currently available tests.

Try to see the parents so you can get a sense of their temperament and overall health and vitality. Ask about the health of the parents and the dogs in the pedigree and how long they lived. Long-time show breeders will know many of the dogs in the pedigree.

Research the breed-specific health issues known to occur within the breed you are interested in (there is plenty of information to be found online). Ask the breeder specifically about these issue in relation to their dogs and the pedigree ... bearing in mind that not every breeder will encounter these problems nor will every dog in that breed develop breed-specific genetic disorders - most will be healthy, long-lived dogs. A breeder who is honestly interested in the health of the breed will not become defensive or dismiss your concerns.

Avoid purchasing puppies produced by very young dogs if you can. Dogs over the age of three are more likely to have revealed any adult-onset problems.

Ask about health guarantees. Most breeders guarantee against genetic disorders for at least five years, others offer a life-time guarantee.

There you are, more practical, common-sense information in a few minutes reading than was offered in the entire Pedigree Dogs Exposed and Best of Breed programs combined.

Are these programs really trying to help to dogs and purebred dog owners or are they more concerned with "awfulizing" show dogs and their breeders for the sole purpose of shocking the general public?

There's plenty of information written here for you to think about. You be the judge!

1 comment:

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