Line breeding!!!!!!!

[Bellasophia]

Inbreeding versus line breeding..

http://bowlingsite.mcf.com/genetics/inbreeding.html

Inbreeding increases the probability of defective( recessive) genes being paired up and thus expressed.Normally out crosses will cover these recessive genes ,since the offspring wil be carriers rather than double carriers of the unwanted trait.
SOme examples quoted,such as rearing birds in captivity successfully ,heavily inbred,simply don't produce a large enough population for the results to be significant.If these captive birds were repeatedly bred,generation after generation then I believe any genetic defects they carried would eventually become more apparent( i.e. Expressed) and the line would detriorate.

 

[ycbm]

This is like the argument as to whether two off pring of a mare are a half brother and sister.

Within dog breeding, people consider line breeding and in breeding to be completely separate. But the fact is that line breeding is a form of in breeding at the lesser end of the scale.

 

[Patchworkpony]

But the fact is that line breeding is a form of in breeding at the lesser end of the scale.

Exactly! If you translate these principles into human form then so called line breeding becomes dangerous to our species - so why is it acceptable in animals?

 

[ycbm]

Exactly! If you translate these principles into human form then so called line breeding becomes dangerous to our species - so why is it acceptable in animals?

Because we knock the obviously bad ones on the head at birth.

 

[ycbm]

Inbreeding increases the probability of defective( recessive) genes being paired up and thus expressed.Normally out crosses will cover these recessive genes ,since the offspring wil be carriers rather than double carriers of the unwanted trait.

This is true but you are completely ignoring the point that in breeding increases the risk of NEW mutations.

These recessive genes all started in a copying mistake somewhere, and in breeding increases the risk of both new recessive problems, like HWSS in Connemaras, or ones which require only one copy like HYPP from the Quarter horse Impressive, who was himself inbred and is the known source of every case of this dreadful disease.

 

[Bellasophia]

I've not found any evidence to say inbreeding causes the gene to mutate...rather the increased incidence of the recessive gene recurring in an inbred pedigree is going to increase the chances of two recessive genes being paired up ,and thus expressed in the offspring produced from these crosses..

Can you post a link that shows the Inbreeding actually causes mutation?

 

[Alec Swan]

Alec, do me a favour and take a good look at the movement, hips and forelimb conformation of the spaniels at the next test or trial you're at. Some of them are quite frankly shocking …….. .

I've been 'watching' spaniels in general for 40 years, and whilst the change has been slow, and almost imperceptible, so we only have to look back say 20 years and see that now a stylish and free moving dog is hard to find. I do agree with you though that there's still a 'head in the sand' attitude to dogs which are clearly wrong in their movement and way of going. It's right that all breeds of working dog should evolve, but the simple fact is that this evolvement is now all too often, a form of regression, in my view.

One interesting observation is that back in the 1970s, Springers with cabriolet fronts were a common occurrence, but now they seem to have straightened up, in the main.

Cockers though are still being bred form which have 'shot' jaws, with many of the top trial people accepting it. I went to buy pups last year and from two very well known trial men-breeders, and all that were left of the litters had poor bites. I pointed out the flaws to both and was met with a shrug of the shoulders.

It's also obvious with Cockers that there has been an outside influence in the breeding of them, with judging by the style and movement of some, there is a clear influence of other breeds of dog being used. Whether this is a bad thing or not, time will tell.

I'm not prepared to comment on Rytex!

Alec.

 

[Dry Rot]

Completely agree with Bellasophia.

How many racing greyhounds have hip problems?

 

[satinbaze]

If you are interested in in breeding coefficient then go into the kennel club website and you can enter registered name of sire and dam and it will calculate the % of inbreeding using all known dogs in the pedigree from the beginning of registration. The only draw back is where dogs are not KC registered or imports which can lead to a "false" low coefficient

 

[Alec Swan]

……..

How many racing greyhounds have hip problems?

Not one that I've ever known. Infact, never have I known any greyhound to have any form of skeletal problems which would be likely to be genetic by origin. Perhaps they exist, but as I say, never witnessed by me.

Alec.

 

[Bellasophia]

Completely agree with Bellasophia.

How many racing greyhounds have hip problems?

( Thankyou dry rot.)
Apparently very few greyhounds have problems with hip dysplasia
However they so have a high incidence of osteosarcoma..the guru vet of greyhounds in USA ,dr couto,discusses osteosarcoma here ..
is it genetic or a result of environmental issues...eg repeatedly pounding excercise trauma from the circular track they run?
http://www.coutovetconsultants.com/blog/osteosarcoma-of-the-hip-in.html

 

[Dry Rot]

( Thankyou dry rot.)
Apparently very few greyhounds have problems with hip dysplasia
However they so have a high incidence of osteosarcoma..the guru vet of greyhounds in USA ,dr couto,discusses osteosarcoma here ..
is it genetic or a result of environmental issues...eg repeatedly pounding excercise trauma from the circular track they run?
http://www.coutovetconsultants.com/blog/osteosarcoma-of-the-hip-in.html

Well, a geneticist would say the PROPENSITY for the breed to get this defect is obviously genetic! But do breeders of racing greyhounds really select for dogs which live a long life?

 

[Cinnamontoast]

I'm pretty sure I read somewhere recently that inbreeding increases genetic issues (or propensity to them) by 8% compared to the more usual potential of 3%. I'm also pretty sure that this was in the Daily Fail article about the mother who met the son she'd had adopted many years ago and is now having a relationship with, so I could just be talking nonsense. :eek3:

Maybe inbreeding or line breeding is to blame for the persistent issue of undershot jaws I see in all the poo crosses I see at the local groomer's.

One of my springers has hip dysplasia. I don't breed, so we didn't send the plates to the BVA, but they ain't pretty

 

[Alec Swan]

I'm pretty sure I read somewhere recently that inbreeding increases genetic issues (or propensity to them) by 8% compared to the more usual potential of 3%. ……..

I often wonder if the figures that we see quoted haven't been simply plucked out of the air! Of course, if we breed from two dogs which share an identical flaw, we run a high risk of replicating the problem. Few would deny that, but the main theme, it seems to me, is that there are those who lay the 'responsibly' for the flaw or problem, at the door of 'line-breeding', and though obviously breeding from unhealthy dogs is the reason for the ongoing problems, careful and considered line-breeding from healthy parents would be unlikely to re-kindle a problem, or would it? I'm not a geneticist so I don't know.

Purely for my own convenience, I do see a distinction between line and in-breeding though it may not be accepted by others. In-breeding, for me anyway, would be immediate parent to child or siblings to each other. Line-breeding would have dogs related but with other influences. Line-breeding also (or should), have a purpose to it. Simply applying the principles of the practice without any thought as to what we're trying to achieve, is pointless.

Alec.

 

[ycbm]

I've not found any evidence to say inbreeding causes the gene to mutate...rather the increased incidence of the recessive gene recurring in an inbred pedigree is going to increase the chances of two recessive genes being paired up ,and thus expressed in the offspring produced from these crosses..

Can you post a link that shows the Inbreeding actually causes mutation?

You are right, I am wrong about this. The inbreeding risk is believed to come only from matching pre-existing recessive genes. In trying to find the information I thought I could find, and couldn't, I came across the statistic that there are over 3,500 known recessive genes in humans. These account for high rates of disability in cultures where it is normal for cousins to marry.

Apologies everyone for my error.

 

[Dobermonkey]

do breed clubs have their own hip score register or is it just bva?

Given it is such an issue I would have thought it in everyone's interest (by that I mean the health of the breed) to try and fathom out what is causing it. someone mentioned they didn't send off their X-rays as they could see they were bad and removed the dog from the breeding pool but surely it would be some how beneficial to others to be able to review scores for offspring before making a decision on puppy purchase / repeating a mating. I have no intention of breeding my boy but sent heart related blood test results to the breed health people to go on their register and was invited to take part in the 'research' that was being conducted at the time and paid the £150 contribution. I just felt for the love of his breed it was the right thing to do.

 

[Bellasophia]

I often wonder if the figures that we see quoted haven't been simply plucked out of the air! Of course, if we breed from two dogs which share an identical flaw, we run a high risk of replicating the problem. Few would deny that, but the main theme, it seems to me, is that there are those who lay the 'responsibly' for the flaw or problem, at the door of 'line-breeding', and though obviously breeding from unhealthy dogs is the reason for the ongoing problems, careful and considered line-breeding from healthy parents would be unlikely to re-kindle a problem, or would it? I'm not a geneticist so I don't know.

Purely for my own convenience, I do see a distinction between line and in-breeding though it may not be accepted by others. In-breeding, for me anyway, would be immediate parent to child or siblings to each other. Line-breeding would have dogs related but with other influences. Line-breeding also (or should), have a purpose to it. Simply applying the principles of the practice without any thought as to what we're trying to achieve, is pointless.

Alec.

Alec.as I see it the problem with using related dogs in a pedigree is ...
they may look healthy but obviously all will be carrying various recessive forms of a gene in their genetic makeup
If you repeatedly use the same dog ,as you will in in true line breeding( it is recommended to use the same dog on both sides of the pedigree more than once to set a trait)then these recessives will have a greater chance of being paired up.
Sometimes the expression of that recessive trait doesn't show up until two generations or more..
There are breed databases which record pedigrees,the various matings a dog has performed,the litters they produced and any health testing is recorded in these databases to allow future breeders to predict the risks of using certain dogs in their pedigrees.The database is only as good as its contributors make it.
recently I health tested my own dog for a condition that his litter brother was shown to be a carrier for..I found out my dog is also a carrier for this condition..we both informed the world famous kennel breeder of our results as she will be breeding their litter sister,to a line bred male( grandfather of the sire is also our dogs father) ...breeder refuses to test the sister of our dogs and will do the breeding regardless...I'm shocked as she has tested for every condition relating to our breed but does not accept the health condition we tested for is " in our breed" .
To me,this is kennel blindness at its best.

 

[Bellasophia]

do breed clubs have their own hip score register or is it just bva?

Given it is such an issue I would have thought it in everyone's interest (by that I mean the health of the breed) to try and fathom out what is causing it. someone mentioned they didn't send off their X-rays as they could see they were bad and removed the dog from the breeding pool but surely it would be some how beneficial to others to be able to review scores for offspring before making a decision on puppy purchase / repeating a mating. I have no intention of breeding my boy but sent heart related blood test results to the breed health people to go on their register and was invited to take part in the 'research' that was being conducted at the time and paid the £150 contribution. I just felt for the love of his breed it was the right thing to do.

I also am not a breeder,nor will I ever breed from my dogs..like you I tested thinking my results would be for the good of the breed..I was heartened by your post as you did the same as I and there are few who would spend money health testing with no intention of breeding.From my heart,well done!
I spoke to my vet recently,she said many test their dogs hips now and if the results are poor they don't register the results and breed anyway,just saying in their puppy ads that the parent is " HIp tested" .The unsuspecting buyer is the one to pay,in all senses.
I also would register a bad hip result as it builds a bigger picture of breed lines and trends within.i



Ybcm..no worries ..it's such a huge topic mistakes are easily made..I thought maybe I was behind the times and some new research was going to be revealed..
...interesting points re human genome.

 

[Alec Swan]

Bellasophia, that's interesting and you raise valid comments. I would say though, that I still believe that the problems which a pup is likely to inherit, will generally be in one parent, the other or both and should be obvious, or at least have the buyer of the pup asking questions, pre-purchase!

There's certainly a long held belief with working sheepdogs that what we're looking for will often 'skip a generation'. I've known of quite useless bitches, with first class sires (and possibly dams), and when bred with, have produced exactly what we want. Along the same lines, it's surprising just how many first class bitches fail to replicate themselves when bred with, no matter what they're put to.

I honestly don't know, and in truth I don't think that there are any clear answers. If there were, then we'd all be breeding the 'perfect' dog, wouldn't we?

Alec.

 

[Bellasophia]

The problem is with recessive alleles they don't show up ie ,the dog is a carrier..it's only when two carriers are bred that the recessive genes get a chance to express themselves.
So if the dogs Were carriers they will go unnoticed in a pedigree unless,as in line breeding they get a higher chance to be recombined with a similar recessive gene down the line.Also carriers will not usually express the illness.
The condition we tested for ( DM) is also not usually going to show up until the dog is about 8 yrs old,so probably will be many years before any affected progeny are registered as affected..
In my case we don't know whether one or both parents are carriers,as breeder refuses to listen to our findings.