Line Breeding...

[Delilahs Mommy]

I was doing some reading on the pedigree's and naturally I started with Delilah's. I noticed that she has the same great great grandfather on her mamas side, then the ggf appears as the great grandfather on her daddys side. Likewise the same great grandmother on mamas side is also the grandmother on her fathers side. Is this what is meant by line breeding? Is there a certain benefit to line breeding? I assuming to keep the "good gene pool".

[CloudClan]

I hadn't seen this when I posted in the other thread, but here is a copy of the Delilah's Pedigree: http://www.woodele.de/maltese/cgi-bin/gene...p;db=maltol.dbw

She is definately line-bred.

Yes, breeders linebreed to lock in certain genes they want to hold onto. Cadeau himself has an out-crossed pedigree. Dreamy was line bred on Fame. Delilah is linebred on Beth and Fame.

Beth is the closest ancestor as Cadeau's mom was Beth and Beth was also Dreamy's grandmom.


Beth's sire Fame also appears on both sides behind Beth, but also appears behind Dreamy's sire "Chase". So Fame is a key ancestor.

[vjw]

QUOTE (dixiepalooza @ Feb 15 2010, 08:52 PM)

I was doing some reading on the pedigree's and naturally I started with Delilah's. I noticed that she has the same great great grandfather on her mamas side, then the ggf appears as the great grandfather on her daddys side. Likewise the same great grandmother on mamas side is also the grandmother on her fathers side. Is this what is meant by line breeding? Is there a certain benefit to line breeding? I assuming to keep the "good gene pool".[/B]

Linebreeding/inbreeding REDUCES the gene pool, thus genetic variability is lost and there's an increased risk of heritable disorders with the practice.

When breeders double up on desired traits for physical conformation, they also double up on genes that can result in decreased fitness and increased disease.



Other countries are way ahead of the US as far as discussions about the health of purebred/pedigree dogs.

Here's a link to from other countries:

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Pedigree dog breeding in the UK: a major welfare concern?

Link to scientific report commissioned by UK's RSPCA


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University of Cambridge's Patrick Bateson wrote a report titled Independent Inquiry Into Dog Breeding:


Link to Patrick Bateson's report




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From the Canadian Veterinary Journal "A New Direction For Kennel Club Regulations and Breed Standards::

Link to "A New Direction For Kennel Club Regulations and Breed Standards




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[MaryH]

QUOTE (vjw @ Feb 16 2010, 02:09 PM)

Linebreeding/inbreeding REDUCES the gene pool, thus genetic variability is lost and there's an increased risk of heritable disorders with the practice.[/B]

Linebreeding helps to lock in genetic traits whether they be for looks or for health. Linebreeding does not automatically reduce a gene pool. Outcross breeding to a popular sire (known as the Popular Sire Syndrome) could reduce a gene pool as much if not more than linebreeding.

QUOTE

When breeders double up on desired traits for physical conformation, they also double up on genes that can result in decreased fitness and increased disease.[/B]

Linebreeding to lock in a good trait does not automatically mean that one or more bad traits are also getting locked in. Case in point -- linebreeding has helped to significantly reduce hip dysplasia.

QUOTE

Other countries are way ahead of the US as far as discussions about the health of purebred/pedigree dogs.[/B]

Here is a direct quote from the Canadian Veterinary Journal referenced above:

The AKC has actually advanced the movement of breeder education and continues to make significant contributions to the growing supply of information regarding canine inherited disease. The AKC Canine Health Foundation focuses on genetic research and veterinary outreach programs that seek to improve the relationship between veterinarians and breeders (27,28). Despite the rigid regulations on genetic variation that still exist, the AKC is beginning to move in an appropriate welfare direction by acknowledging and researching canine hereditary diseases.

I have not read the other articles yet but hope to later this evening. Quite a bit of the CVJ article focuses on new breeds and the importance of starting with a large gene pool and setting some guidelines for that. I think it is fair to say that if we knew 100 years ago what we know now, we'd have done some things differently. The same could be said about all walks of life, right? What disturbs me a bit about the CVJ article is that it has left some with the impression that breeders do know and don't care. That is so not true about the breeders I know and respect. In closing, the Maltese breed has been around for thousands of years, it is not newly created. Our standard has not changed in decades so as a breed club, we are not rewriting anything to go along with the latest fad. And we're not in a bad place overall when looking at the COI (coefficient of inbreeding) of most of the Maltese out there today.

MaryH

[miccomte]

You can easily compute the amount of inbreeding of your dog by reading its pedigree:
Inbreeding calculation

[lilygirl]

Originally Posted by miccomte

You can easily compute the amount of inbreeding of your dog by reading its pedigree:
Inbreeding calculation

That is awesome! I have been looking for one of these.

[miccomte]

Good that you appreciate that.

[CeeCee's Mom]

Originally Posted by CloudClan

I hadn't seen this when I posted in the other thread, but here is a copy of the Delilah's Pedigree: http://www.woodele.de/maltese/cgi-bin/gene...p;db=maltol.dbw

She is definately line-bred.

Yes, breeders linebreed to lock in certain genes they want to hold onto. Cadeau himself has an out-crossed pedigree. Dreamy was line bred on Fame. Delilah is linebred on Beth and Fame.

Beth is the closest ancestor as Cadeau's mom was Beth and Beth was also Dreamy's grandmom.


Beth's sire Fame also appears on both sides behind Beth, but also appears behind Dreamy's sire "Chase". So Fame is a key ancestor.

Fame is CeeCee sire (Father) I see Fame when I look at CeeCee

[k/c mom]

Originally Posted by miccomte

You can easily compute the amount of inbreeding of your dog by reading its pedigree:
Inbreeding calculation

Hi and welcome to SM!

The chart you linked to is great and really helps people like me who are clueless on this topic!

I have a question, though... how many generations do we need to look at?

[miccomte]

In fact, you should look as far as you can. The deeper the pedigree, the higher the inbreeding will be.
Only one thing should be kept in mind: when comparing two inbreeding coefficient (for example when a breeder wants to choose a sire suitable for his bitch), the two calculations should be done on the same pedigree depth.