Thread: inbreeding- what are your opinions ??

I have had a couple of enquiries about doing a stud on my dog who is a Fax vom Grenzganger grandson linebred on Fax and Fax's parents with other Fax linebred bitches. IMHO the linebreedings he produces over Fax line bitches are an abortion sometimes including up to 22 other dogs suffice to say that I politely rejected the matings given that many of these Fax lines are so heavily cluttered, bred and over bred, I would only consider using my dog on an outcross as I believe his linebreeding/inbreeding is already way out of hand diluting the traits that these great dogs once had?

Hi all, Inbreeding/Linebreeding/Crossing, does not create undesirable genes it simply increase the chance of the bad traits that are already present. its a recisve gene when the dog and bitch carry the unwated gene they will produce 25% normal pups that will not throw bad genes, 50% will look normal BUT will produce you unwated genes, 25% will be visable with the faults. JMHO

I am not a fan of it myself.Nothing wrong with linebreeding but dont see the need for inbreeding.Most of the times I hav seen it done is by novice breeders breeding show dogs from there own dogs and thinking they have something special.Unless you hav owned the same line of dogs over many years and you have culled out the weaknesses in them and no the history of parents grandparents greatgrand parents I dont think you have any place inbreeding for the sake of it.The only reason I can see for it is if you are working on a limited genepool or with rare animals and no option to obtain anything else.I believe what Jim says it sdoesnt automatically produce faults but it is the quickest way to bring them to the fore if they are there and have the opposite effect of what you want.
Dont really see a need for it I would rather breeed best to best on any given day.

The idea of line breeding is to reproduce the dog you are line breeding on. The close father daughter matings hope to fix certain genotypes. Whether these refer to desired physical features or behaviours doesnt matter. Show breeders want the physical and working breeders want the temperament.
Breeders who have done a good line breeding will have litters with very good uniformity as the genetic variation of the genes at specific locations is very close to zero. When you do an outcross the genetic variation is so great that you get lots of variation among the offspring. (Dogs within breeds in general don't have much genetic variation, thats why most breeds are identifiable).
As stated above you run into problems when a defect is a recessive gene. ie. The dog will carry one copy(allele) of the bad gene and one copy(allele) of the good gene(they get one allele from each parent) but the dog doesn't show any defect due to the good gene being dominant. When you breed two genetic similar dogs both carrying the defect gene you increase the chance of that hidden defect gene being passed on to the offspring with no dominant normal gene present.
It is fact that every dog carries genetic defects. If you were to breed it with a genetically identical mate you would have 25% of the puppies showing the defect. It sometimes amuses me that breeders will guarantee that the dog/pup is free from genetic defects as this is not possible as every living animal carries genetic defects on a DNA level. Free from visible (or expressed) defects is a more valid argument. This is attributed to the genetic heterozygosity of the animal. ie the dominant gene hiding the defective gene. Thats the beauty of sexual reproduction.
I would be happy to linebreed ( inbreed) on a perfect dog in the hope to recreate it. You just have to cull heavily to get rid of the visible genetic defects.
Inbreeding is the way we have produced chickens that lay incredible numbers of eggs, cows that produce tens of litres of milk and pigs that produce bacon fast
It is really about efficiency in the end.

Originally Posted by Jonathon Howard

The idea of line breeding is to reproduce the dog you are line breeding on.

I agree with the above statement Jonathon which is ideally correct, but when I was looking for a GSD pup there were several litters I came across said to be linebred on Fax vom Grenzganger who was a great dog which sounds good. However, every breeding except the one I ended up choosing were linebred on Fax but also linebred on up to 14 other dogs unrelated to Fax, sometimes linebred on 6 different dogs in the 3rd generation?.

In these examples, who is the litter really linebred on and what is the breeder trying to reproduce from the linebreeding in such a breeding?

You're working on the clear cut theoretical world of Autosomal inheritence. That is your black/white, two alleles of the one gene one good one bad. When you have two dogs that are carriers of a recessive trait (ie one copy of a dominant, and one of a recessive) the pups have a 25% chance of being homozygous recessive, not that a guarenteed quarter of your litter will be recessive. There is a greater chance that usually your pups will be homozygous dominant, or carriers of the recessive gene as a lot of homozygous recessive individuals (depending on what the gene does) usually do not form (especially metabolic faults). Nature culls for you.

In the scheme of canine genetics this is only a small proportion of inheritable traits that comply with this. Remember some genes have multiple alleles, some phenotypical characteristics are multi-gene mode of inheritance then there is also sex linked traits. Sometimes inbreeding and line breeding can be a wonderful thing, just like sometimes outcrossing lines can be shooting yourself in the foot with the crap your bitch is about to drop. If you want to reproduce what you have and you do it in a smart way (ie you know your lines and you know what limits you can go to with breeding) it can work a treat. I've seen some magic dogs come out of close matings. But I think really there is no service to the breed doing what that lab breeder has done, unless they were trying to really see what was in their lines as more an experimentation. I know a few people have done stupidly close matings to make the more recessive conditions pop out so they know what they have.

Hip and Elbow dysplaysia though ... now we see some absolute shockers pop out of crossbreed dogs, unrelated lines etc. There's so many genes that go into the formation of the dogs joint, then there is environmental elements that can contribute as well. Saying that inbreeding is the sole cause of that dogs skeletal problems may not be 100% true. But you probably could say it was a big contributor if the parents had some bad conformation carried in their lines.

Get on to pedigree database and search Sips ter Heide in the pedigree search, Malinois section.
In the old days they certainly didn't mind inbreeding.

Ann-Marie if you use the above site to track down the "14 dogs" pedigrees you may find that Fax and these dogs do share many common ancestor further back.

Originally Posted by Martin

Get on to pedigree database and search Sips ter Heide in the pedigree search, Malinois section.
In the old days they certainly didn't mind inbreeding.

Ann-Marie if you use the above site to track down the "14 dogs" pedigrees you may find that Fax and these dogs do share many common ancestor further back.

wow. Now thats inbreeding! Saying that have a good read of some of the de Jolimont Mals on there ... the pedigrees are all over the place and definitely wrong (pedigree for a dog born in the future?)