Friday, 15 August 2008

Pedigree Dogs Exposed

Don't know if you've seen this announcement from Imperial College issued today. But it is deeply disturbing.

We all know that inbreeding - mating close relatives together - is obviously a very dangerous game. Nothing new here. But Professor David Balding used the Kennel Club's database of pedigees to analyse just how closely related dogs in several breeds actually are.

The researchers' analysis showed that, for example, Boxer dogs were so closely related to one another and had such little genetic variation between them that genetically, 20,000 dogs looked like a population of about 70. In the Rough Collie breed, 12,000 dogs looked in genetic terms like a population of about 50.

Professor Balding was quoted as saying: "The idea that inbreeding causes health problems in particular dog breeds is not a new one, but we believe ours is the first scientific study to explore this issue and analyse the extent of inbreeding in a systematic way, across many breeds. We hope that following our work, dog breeders will make it a high priority to increase the genetic diversity within different breeds. Otherwise, we will see growing numbers of dogs born with serious genetically inherited health problems."

The report says: "Such small effective population sizes mean that the chances of a dog breeding with a close relative, resulting in birth defects and genetically inherited health problems, are high. The researchers argue that those involved in breeding dogs should encourage breeding from a larger pool of potential mates in order to create greater genetic variation and lessen dogs' chances of inheriting genetic disorders. They suggest measures such as limiting how many times a popular dog can father litters; encouraging mating across national and continental boundaries; and relaxing breed rules to permit breeding outside the pedigree."

Surely the KC will find it very hard to allege bias if the whole scientific community are saying "panic".

But the KC is trying to convince themselves that everything is still okay - they've got it all under control. That the only people who say otherwise are very bad biased people with issues.


I have to say some of the behaviour on the dog show forums where the BBC1 documentary has been discussed has been really quite shocking. Some of the pack are obviously very scared of this programme and some of them are getting nasty, calling the producers of this documentary "evil" just for asking them difficult questions about health issues in the usually safe enclave of their own dog shows and forums.

I know there are free-thinking breeders who question the status quo and worry about the future of their breeds who will watch the programme with an open mind and a heavy heart. Hopefully they will be brave in the coming days and their voices will be heard, too - and not just these short-sighted luddites who are an embarrassment to the pedigree dog world.

The brilliant blogger Terrierman has already had a good read of the report and here is his summary....

  1. The study is based on a 10-breed sample of 2.1 million dogs in the Kennel Club's electronic pedigree data base. The Kennel Club's database contained records of a total of 5.7 million dogs from 207 breeds as of the end of 2006. The Kennel Club's electronic data base was begun in 1970.


  2. This is the first systematic attempt to study Kennel Club population structure using The Kennel Club's own pedigree database.

  3. The 10 breeds examined were: the Rough Collie, the Golden Retriever, the Boxer, the English Bulldog, the Chow Chow, the Greyhound, the German Shepherd Dog, the Labrador Retriever, the English Springer Spaniel, and the Akita Inu.

  4. The researchers note that inbreeding condenses and exacerbates genetic disorders with a population:

    "Dog breeds are required to conform to a breed standard, the pursuit of which often involves intensive inbreeding .... This has adverse consequences in terms of loss of genetic variability and high prevalence of recessive genetic disorders. These features make purebred dogs attractive for the study of genetic disorders, but raise concerns about canine welfare."

  5. The researchers note that many dog breeds are associated with specific genetic disorders that have been magnified by inbreeding:

    "Many diseases affecting dogs have high prevalence in one or a few breeds, such as Addison’s disease, common in Portuguese Water Dogs (Chase et al., 2006), interstitial lung disease in West Highland White terriers (Norris et al., 2005), and dermoid sinus in Ridgeback dogs (Salmon Hillbertz et al., 2007)."

  6. The authors found disturbingly high levels of inbreeding within most Kennel Club breeds they looked at:

    "We find extremely inbred dogs in each breed except the Greyhound, and estimate an inbreeding effective population size between 40 and 80 for all but two breeds. For all but three breeds, more than 90% of unique genetic variants are lost over six generations, indicating a dramatic effect of reeding patterns on genetic diversity."

  7. The number of generations studied ranged by breed from 5.9 in Greyhounds to 9.0 in the German Shepherds, with an average over the ten breeds of 8.0 generations of dogs analyzed.

  8. Popular sires are part of the problem, but not all of the problem.

    "Popular sires (defined here as > 100 recorded offspring) are evident in all breeds except Greyhound. Golden Retrievers have the largest proportion of popular sires (10%), and conversely the lowest proportion (5%) of male dogs that are sires. . . . Highly-prolific dams (> 40 offspring) are concentrated in three breeds: German Shepherd, Golden Retriever and Labrador Retriever. Most dams have just one litter recorded."

  9. A closed registry system is the core of the problem.

    "Dog registration rules have only been rigidly enforced for about 50 years, prior to that occasional outcrossing was still possible."

  10. The Kennel Club needs to change the way it does business.

    "We have found that the loss of genetic diversity is very high, with many breeds losing over 90% of singleton variants in just six generations. On the basis of these results, we concur with Leroy et al. (2006) that remedial action to maintain or increase genetic diversity should now be a high priority in the interests of the health of purebred dogs. Possible remedial action includes limits on the use of popular sires, encouragement of matings across national and continental boundaries, and even the relaxation of breed rules to permit controlled outcrossing."
Please also have a look at the last post - also on Pedigree Dogs Exposed...

11 comments:

Jontus said...

Great post, thanks for forwarding this info Beverly.
To be honest I followed your comments the other day about Sweden with interest ---as I'm based in Stockholm and breed bassets.

Here in Sweden we've got a very worrying case of one or two breeders really dominating and I'm highly cognisant that this could damage the breed in just a generation, given that the population is so small.

We had a programme on Swedish TV last year similar to the one you're talking about in Britain and it prompted the judges to hold a conference and outline new guidlines to stop overtyped dogs being rewarded in the ring.

It seems we're both accutely aware of the problems but at the same time breed clubs aren't doing enough to be open about the problems.

Mina said...

I know show Greyhounds are different from racing Greyhounds, but this bit did make me nearly choke.

"Popular sires (defined here as > 100 recorded offspring) are evident in all breeds except Greyhound."

My Greyhound (ex-racing) has over 7000 siblings.

Beverley Cuddy said...

Hi Mina

The research is from the KC database I believe - I guess the racing world has their own registry? But still it seems odd as i would have thought there were very few greyhounds bred within the show system so a small gene pool!

My god - 7,000 siblings - a terrifying level of breeding.

Cheers
Beverley

alfmcmalf said...

Beverley

One of the co Authors of this report is none other than Jeff Sampson.

Beverley Cuddy said...

The irony wasn't entirely lost on me! It is indeed the KC's own geneticist.

I gather he just provided the data, although it's hard for them to claim this report is biased isn't it!

L said...

Your blog is excellent! It's good to know there are dog breeders looking toward the long term health of purebreds. Horses are going through many of the same issues. Are there any breeds of domestic animals not being deformed by fad following owners?

Janeway69 said...

I wish I could get this documentary in America, but I don't get BBC One. As much as I fall for many breeds as much as any person, I do feel that many of them are freaks. ANd when some scientist was quoted as saying this would be criminal if we bred people this way, I find myself agreeing; I have had these very thoughts myself, esp when looking at bulldogs and dachshunds.

Talk-Pets said...

I was disgusted with the programme Pedigree Dogs Exposed - some claims that it attacks the entire showworld, others that it attacks all breeders. I didnt see it that way but I saw some valid points being raised that we need to take seriosly and pref soon.

jenny said...

A related blog post by a UK vet discusses some of these same issues - I think your readers may be interested in what she has to say about the BBC programme and about pedigree dog breeding in this country!

Cait said...

I saw some valid points, I saw a lot of stuff I didn't like, too, though- I've posted about this over on Pet Connection and don't feel like restating it all here.

One thing I'm curious about though, is what adding the smooth collies back into the Rough Collie population would do for their count. They're separate in the UK, but not here in the US.

I'm disgusted by the portrayel of breeders that the show gave, but it's not really a surprise to anyone, I think, that bad breeders exist in the show fancy just like anywhere else. (I'm SERIOUSLY annoyed though, that people are reading this as NORMAL for people who show- because in my experience, it's not, at ALL.) Overall, though, it raised more questions for me, which I guess is the point- but I don't know how they're going to ehlp anything.

Anonymous said...

For another viewpoint of the Imperial study:

http://blogforshowdogs.blogspot.com/2009/04/are-genes-really-lost-forever-with.html