Line breeding and outcrossing -a paper

[Eceni]

The occasional accident isn't the point (look at the Ptolemies, they survived 3 generations before they began to degenerate) the point is that when it's sustained, so that the CoI of a dog is routinely over 25%, then you begin to store up trouble - if for no other reason than the fact that the dog's immunity depends on its genetic diversity. I can dig out the basics on Major Histocompatibility Complexes if you want, it makes sobering reading - the essence is that the diversity of MHCs is directly related to genetic diversity. High CoI == low genetic diversity == reduced numbers of MHCs == reduced ability to withstand infection.  If you take it to its logical limits, you get the lab mouse which has to live in a sterile environment, or at least be protected from known antigens to which it no longer has the immunity that was a given in the wild type.

short term accidents are not a disaster, just unfortunate.  Long term, protracted reduction of genetic diversity is just plain daft.

e

[Cob-Web]

the point is that when it's sustained, so that the CoI of a dog is routinely over 25%, then you begin to store up trouble -

I agree with this - but how many dogs do you actually know with a CoI this high?   

I would hazard an educated guess that the type of breeder who produces puppies with this level in inbreeding are the type that COL advises people to avoid for all sorts of other reasons - commercial breeders, puppy farms and backyard breeders, not knowledgable breeders who research and plan their breeding programme.

I have two "line bred" dogs - their pedigrees would probably make you shudder - but their CoI are nowhere near as high as you suggest 

[Eceni]

In the last breed I was looking at seriously - and to which I had good access to a lot of pedigrees - a friend who's a geneticist did a bunch of CoIs for me

none were less than 15%, several were in the 40s - and actually, this is a diverse breed, not over-bred with performance/working strain and show strain like the cockers.  If I had access to cocker pedigrees up to 10 generations (less than that's largely irrelevant), we could get the CoIs done but I don't have the software. If you look at a 5 gen pedigree, and there are more than 2 or 3 repeats, then you're looking at a CoI of nearing 20%.

e

[Helen]

that's really interesting -  I'd say even without looking at the peds on the board that more than 2 or 3 repeats is very common...

[Roslyn McConnell]

It is so sad that the very people who need to read these comments (i.e. the 'bad' breeders) are exactly the type of people who would not be interested in loggin on to these sites! 

I just really wish that breeders needed a licence and could be vetted and then maybe we would hear less of the heartbreaking horror stories resulting from cash orientated breeders. I also wish that breed standards could be relaxed alittle and a limit put on littler numbers per dog to avoid the temptation for  inbreeding amongst the overly ambitions show kennels.

Wolf packs have an alpha male and female....and only this couple will mate in a given season, subordinate females don't even come into season and as said before the males usually join another pack on maturity so they effectively prevent the whole pack from inbreeding. It has been said that dogs are wolfs that never grow up, we have been breeding in desirable juvenile behavioural traits in the domestic dog for thousands and thousands of years, resulting in an animal which is similar in temperament to a wolf puppy, so selective breeding it's necessary the problem, it's the inbreeding which is..............

>90% of unique genetic variants are lost over six generations with inbreeding (Calboli et al. Genetics Journal 2008 179(1):593-606)

Increasing the inbreeding co-efficient of puppies by just 1% led to 0.06% increase of still birth in dachshund puppies (which is actually very large for just 1%) (Gresky et al. Berl Munch Tierztl Wochensch 5005 118(3-4) 134-9.)

Pedigree dogs are so homozygous that they are now been used as genetic models for autoimmune diseases such as Addison's disease in the Portuguese water dogs ( Chase et al. International Journal of Immunogenetics. 2006 33(3): 179-84)

I think we have been really lucky with the cocker's so far, partly though responsible breeding and partly due to their large population numbers.....I shudder to think what health problems await certain over breed lap dogs in 50 years!

But I would urge anyone not to breed/buy puppies from this 'inbreeding' practice, yes I know there have been many puppies which seem to be unaffected by this buy how many of their littler mates weren't so lucky and why would you knowingly want to take such a  high risk? That fancy pedigree might get awfully expensive in vet bills!!!!

It is interesting that the Amish Jews were brought up, I remember attending an ethics seminar as there is an extremely high incidence of Tay Sachs diseases amongst this group, marrages are arranged and the marrage maker wanted the results of everyones genetic tests so as to not match two carriers together. In human terms this disease manifested itself very quickly compared to the level of 'inbreeding', it's all to do with 'penetrance' and a huge complicated issue of allele selection, which means a little inbreeding could be enough to see BIG problems . So while I think the cocker spaniel population isn't going to shrivel up and die tomorrow I think it would be wise not to get complacent.

It is good to do whats best for the breed but better to do whats best for the individual dogs. But then I think everyone here already does, otherwise they wouldn't log on...........just wanted to get all that all my chest really! 

[Cob-Web]

If you look at a 5 gen pedigree, and there are more than 2 or 3 repeats, then you're looking at a CoI of nearing 20%.

that's really interesting -  I'd say even without looking at the peds on the board that more than 2 or 3 repeats is very common...

.....interesting, but not always the case - in his 5 gen pedigree, Molo has one bitch that appears 4 times and another four ancestors (2 males, two females) which appear twice each - but his calculated CoI is not even close to 20% 

This is why, as Roselyn says, it is not productive to generalise like this, and to look at individual breeders practice and the background to the individual litters.   It would be a shame if prospective owners ignore reputable breeders because a litter is linebred in favour of a litter from a less informed BYB who has mated their bitch with the dog down the road with no consideration give to compatibility or health 

The academic ideals are fine on paper, but the realities are very different, and with the calls for a ban on all breeding on one end of the scale, and illegal commercial mills churning out puppies at the other end, I think that these issues around the CoI pale into insignificance 

If I had access to cocker pedigrees up to 10 generations (less than that's largely irrelevant), we could get the CoIs done but I don't have the software. If you look at a 5 gen pedigree, and there are more than 2 or 3 repeats, then you're looking at a CoI of nearing 20%.

Well, as it happens, we might be able to help you out there......

http://www.tenset.co.uk/downloaddemo.html

http://www.cockersonline.co.uk/discuss/index.php?topic=11772.0

[tiamaria]

"But I would urge anyone not to breed/buy puppies from this 'inbreeding' practice, yes I know there have been many puppies which seem to be unaffected by this buy how many of their littler mates weren't so lucky and why would you knowingly want to take such a  high risk? That fancy pedigree might get awfully expensive in vet bills!!!!"

How would the average person know this kind of information when looking a buy a puppy?

[Jane S]

I just really wish that breeders needed a licence and could be vetted and then maybe we would hear less of the heartbreaking horror stories resulting from cash orientated breeders.

There already is a licensing system for breeders who have more than 4 litters a year but as with any legislation, it's enforcement that's the issue. Local councils are responsible for licensing breeders but councils don't always have the resources or the will to ensure all breeders that should be licensed are licensed (hence the number of unlicensed puppy farms that seem to flourish in certain rural areas). If you propose that ALL breeders should be licensed, then as usual it will be the small minority of responsible breeders who will voluntarily comply and the other type will just carry on as normal & use every loophole available to avoid getting caught.

I also wish that breed standards could be relaxed alittle and a limit put on littler numbers per dog to avoid the temptation for  inbreeding amongst the overly ambitions show kennels

There already is a limit in place for KC registered litters (too many in my opinion but that's another issue) but huge numbers of litters are either not registered or are registered with other commercial registries who have no limits. I'm not sure why you have decided that it's the show breeders who need limiting to avoid the temptation to have too many inbred litters when the fact is show breeders make up a small percentage of the breeders out there. Any study of litter registrations reveals many, many commercial breeders who produce large numbers of litters ,all sired by one or two resident stud dogs and they will keep doing this time after time,year after year. It gets a bit galling for show breeders to be continually labelled as the bad guys - of course some are but people need to realise that the vast majority of puppies bred (in Cockers anyway) do not come from show breeders.

[Eceni]

.....interesting, but not always the case - in his 5 gen pedigree, Molo has one bitch that appears 4 times and another four ancestors (2 males, two females) which appear twice each - but his calculated CoI is not even close to 20% 

Could you show the working for that?

e

[Eceni]

Well, as it happens, we might be able to help you out there......

http://www.tenset.co.uk/downloaddemo.html

http://www.cockersonline.co.uk/discuss/index.php?topic=11772.0

Thank you!   <dances>

e

edit - Rats     I have a Mac, won't open a .exe file... got any Mac downloads?

e

[Cob-Web]

.....interesting, but not always the case - in his 5 gen pedigree, Molo has one bitch that appears 4 times and another four ancestors (2 males, two females) which appear twice each - but his calculated CoI is not even close to 20% 

Could you show the working for that?

e

I could, but it might take me a while - I rely on the software to do it for me   When I have a spare few hours, I'll sit down and do it by hand and PM it to you 

[KellyS]

Any study of litter registrations reveals many, many commercial breeders who produce large numbers of litters

One particular copy of the breed supplements I have shows over 20+ litters in one quarter from one breeder

[Helen]

it's not just show breeders - at the moment a lot of working cockers are being bred and sold according to the amount of 'red' (FTCH) in their pedigrees.

It's not unusual in a 5 gen pedigree to see repetitions several times - I was offered a pup with an 'outstanding' pedigree, 45 ftch's in it's pedigree....1 dog appeared 5 times, 4 dogs were repeated 3 times, 8 dogs twice...

[Eceni]

it's not just show breeders - at the moment a lot of working cockers are being bred and sold according to the amount of 'red' (FTCH) in their pedigrees.

It's not unusual in a 5 gen pedigree to see repetitions several times - I was offered a pup with an 'outstanding' pedigree, 45 ftch's in it's pedigree....1 dog appeared 5 times, 4 dogs were repeated 3 times, 8 dogs twice...

This is the kind of thing that needs to be given a bad name... Cobweb's quite right, of course, some line breeding is intelligent and moves the breed forward, it's just that some who know nothing of genetics have got the idea that 'a little bit of shared blood is good,so lots must be very, very good' which isn't the case at all.   People who know next to nothing are breeding close cousins/siblings/parents because 'that's what the professionals do'.  Until and unless there's a concerted campaign to inform them - and the buying public - not to touch them with a bargepole, it'll carry on.

And the problem with that is that the KC is stuffed with people who will swear blind that line breeding IS a good thing - that the Swedish KC is mad not to allow close related breedings and that they've been doing it for 50 years so it must be OK.  The fact that they've been doing it for 50 years and this is exactly why it's NOT OK escapes them....

but small bits of facts get through and there are people in each breed now who are beginning to understand.  What we need is to work out a way forward that keeps the breed going without upsetting those who set the trends - who aren't the BYB or the puppy farmers.  I don't know what it is, though....

e

[Roslyn McConnell]

Jane S- I did not mean to label the show breeders as 'bad'.....far from it!!!! The point I was trying to make was that there are good and bad breeders in both those groups that show and those that do not, and the problems can range from those who know nothing of their dogs pedigrees and just use the nearest stud to those who know everything but still use an unsuitable stud because of his show merits. There are also very very good breeders out there from every walk of life so I did not want or mean to catergorise anyone......sorry if it seemed this way! I have heard about the licencing for kennels with large litter numbers, I suppose I very naive in thinking that if it was extended it would help solve the problem......I live in a world of rainbows and butterflies sometimes! 


Tiamaria- thats the question I would love to know the answer to as well! If you know nothing about breeding it can be very hard looking at the pedigrees plus a lot of dogs are sold without them.......and breeders could lie! Puppy farmers get very crafty with placing pups inside homes for viewings so as Jane said, Im sure they could find loopholes in any legalisation that was brought out.
It such a minefield for the new puppy owners and I think it is terrible that there are people out there just out for the money, yes a breeder has to cover their costs but I've seen a litter of 5 Samoyeds advertised for £1500 each!!!  Ive never raised a litter but surely £7500 is a bit excessive? There is just something about using puppies as an income that doesnt sit well with me, or am I being sentimental again?