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Genetics, Health And Breeding?

This is all very interesting and certainly a lot of food for thought. Ive been breeding dogs for thirty years and its true you never stop learning and nor should you and ofcourse in aperfect world breeders would happily turn their pedigree's over for examination and information that would help "them", us, avoid health pitfalls . That however is not going to happen so for the time being we have to rely on each others honesty.

Nicky
 
UKUSA said:
This is all very interesting and certainly a lot of food for thought. Ive been breeding dogs for thirty  years and its true you never stop learning and nor should you and ofcourse in aperfect world breeders would happily turn their pedigree's over for examination and information that would help "them", us, avoid health pitfalls . That however is not going to happen so for the time being we have to rely on each others honesty.Nicky

Click to expand...

Ok, I do know nothing at all about the politics of dog breeding, but I have been browsing happily on the Whippet Archive for the past few days...

if the pedigrees are on there, are they not in the public domain? Is there a secret stash of whippet pedigrees somewhere? (Or all other breed pedigrees?)??

confused now

not that it matters - it would take a concerted will by the overwhelming majority of breeders to change the system before something could be done...

but I really would like a whippet. I've had a lurcher and she was lovely... but whippets seem like a step forward, not back. Just that I want one that'll be healthy (and guaranteed to win at agility, of course... :)

m
 
My parents were complete outcrosses. My mother's family produces diabetes ,which is an inherited disease, no matter who they are coupled with. If diseases are recessive genes, how do you explain this? My father's family and the families who my mother's siblings married into had no diabetic history. Maybe they were carriers, but all nine families? I don't think so. After all, it happens with humans and our gene pool is a whole lot more diverse. So are we sure that outcrosses don't bring problems into our lines?
 
clayelem said:
My parents were complete outcrosses.  My mother's family produces diabetes ,which is an inherited disease, no matter who they are coupled with.  If diseases are recessive genes, how do you explain this?  My father's family and the families who my mother's siblings married into had no diabetic history.  Maybe they were carriers, but all nine families?  I don't think so.    After all, it happens with humans and our gene pool is a whole lot more diverse.  So are we sure that outcrosses don't bring problems into our lines?
Click to expand...

not all diseases are recessive. If your mother's family produces diabetes regardless of the outcross, then that form of diabetes is dominant by definition

but if your mother were a whippet, you wouldn't breed from her

we're assuming responsible breeding, which means you're not breeding with obviously affected animals, so by definition, the diseases that arise are recessive.

to put it more simply (I am trying, honest), if you cross your whippet with a GSD, you'll get a dog with a degree of hip dysplasia - which is why you wouldn't do that.

conversely, if you cross your whippet with an apparently normal border collie which carries Collie Eye Anomaly as a recessive, the offspring my carry the gene. You won't see it until several line-bred generations (it could easily take 9 - all these things are a roll of a dice) until you see CAE in this 'line.

numbers are complicated. There's a brilliant book on horse genetics where the author had a mare she thought was homozygous for non-bay (she was a chestnut but bay is a modifier). It took 10 matings of this horse to the same black stallion to get a bay colt proving she was a carrier of the bay modifier gene. This is a gene that's a simple autosomal - so each foal had a 50% chance of it being bay. SO the odds were long, but not too long

that's why test matings of stallions are so much easier than mares. At least bitches have multiple litters...

make sense?

m
 
Eceni said:
clayelem said:
My parents were complete outcrosses.  My mother's family produces diabetes ,which is an inherited disease, no matter who they are coupled with.  If diseases are recessive genes, how do you explain this?  My father's family and the families who my mother's siblings married into had no diabetic history.  Maybe they were carriers, but all nine families?  I don't think so.    After all, it happens with humans and our gene pool is a whole lot more diverse.  So are we sure that outcrosses don't bring problems into our lines?
Click to expand...
not all diseases are recessive. If your mother's family produces diabetes regardless of the outcross, then that form of diabetes is dominant by definition
Click to expand...
That has been the pattern with thyroiditis / early onset Type 1 diabetes in my family, and I have spent a lot of time looking at articles on the pattern of inheritance in humans. However, since I became affected and started researching, other relatives on the sides we thought unaffected have subsequently developed thyroiditis later on in life, so maybe they just have a different pattern of developing the same disease for some reason. In fact the genes may have been present on both sides of the family, and some individuals were lucky and didn't encounter the environmental triggers. As has been said, some conditions may involve an unknown number of genes and have a more complex pattern of inheritance.
 
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Not all genes which are deleterious in duplicate are recessive.

For example, in Collies and shelties, the Merle gene M is a dominant color gene which is benign in the heterozygous state, giving simply the blue merle coat coloration which is fancied by many. But breeding two Merles together gives 25% MM 50% Mm and 25% mm (not merle).

MM is what is known as lethal in the since that double Merles are usually deaf with significant eye abnormalities Merle Ocular Dysgenesis which also make them blind. By lethal, breeders don't mean it makes them die, but these defects would certainly give them little chance of survival in the wild state.

But most deleterious genes are recessive if they are "simple", IOW, if the deleterious trait is the result of a single gene pair.

In my case, I do know of a recessive genetic issue that affected a portion of my line. I nailed down the exact ancestor who introduced it to my line, and I did this by pedigree analysis and tight crosses. It was not a happy time for me as a breeder. A lot of my fellow breeders strongly disapproved and felt I should just walk away from 15 years of mostly successful work and go buy new dogs who weren't "tainted" by my public admission of having uncovered a health problem. This problem, btw, was one which could be easily found in puppies before they left me. And it was one that was neither painful nor expensive to treat.

However, if I had never linebred onto that ancestor, I would not have ever seen the problem in all likelihood. But as a successful breeder, some of my buyers undoubtedly would have doubled up on him and they would have seen it (and a few of them did). So, the linebreeding didn't create the problem, it just allowed the problem to surface and be identified. This is a very common situation in purebred animals. If a DNA marker exists for it, then you can eliminate it in two generations. If one does not, it's a bit trickier, but still manageable.

But now I know what not to double up on. If I do not double up on that particular ancestor, then I have not seen a recurrence of that problem. But I am also dependent on other breeders to be honest with me if it is also a problem they have seen, because if it is present in other portions of the North American gene pool, then I may run into again by accident. Working within lines I know well, and with breeders I trust, I can avoid it. Each outcross is to some extent a risk. I do more outcrossing now, but I also do not fear to linebreed so long as I avoid that problem lineage. There's 7/8th's of the rest of the pedigree to choose from.

So, for me, in terms of not seeing that one simple recessive defect again, working within my line is as safe as outcrossing, and perhaps safer if I feel I cannot rely on the honesty of other breeders OR if that breeder has just done outcrossing and therefore would not know if they carried the problem through some portion of their lineage or not. I have come to find out I was very far from the first person and certainly not the last to see this defect, but so far, I'm one of the very few who has admitted to it. Without the gossip pipeline helping me on the Q/T know who to avoid, I'd feel completely hung out to dry.

With polygenetic problems (those caused by the combined action of more than one gene pair), it's a lot harder. Those genes may be spread throughout the breed. I think that most of the problems we are talking about with regard to things like AI and cardiac issues are polygenetic. It's much easier to couch everything in terms of simple recessives, but not all genetic defects are the result of a simple recessive.

I feel linebreeding introduces more of a risk of concentrating genes which are deleterious in multiples. You are increasing your probability that all the genes needed to produce a predisposition to a problem will occur in a given individual in your litter. This is what I feel has happened with cardiac in the US. The original carriers of a proportion of these genes did not sire a ton of heart problems in their original litters. Their litters were really good, which is why they became cornerstone producers. If they had thrown a ton of problems, they'd not have been used and crossed back onto so much. It was only through concentrating the genes via repeated tight crosses that the bulk of the necessary polygenetic factors required to manifest a mitral valve condition at an early age were made present in our show gene pool at an greatly increased probabilities. Genetics is mostly a matter of statistics and probabilities. Your probability of being dealt a Royal Straight is greater if you increase the number of face cards in your deck relative to non-face cards.

This is just my personal opinion, too, based on experience and observation. But I do have a leg up on a lot of my fellow breeders in that I hold a degree in Zoology, with a minor in statistics.

Coefficients of Inbreeding are, to me, not nearly as helpful as a candid conversation with an honest breeder who has worked a given line for several generations, and done some tight breedings with it, and seen what genetic skeletons are lurking. I don't believe there's any such thing as a totally clean line. Everyone has something lurking in their pedigrees--they just may not have done the right cross yet to become aware of it.

Right now, with cardiac, I am trying to find pedigrees where no close-up ancestors have shown evidence of mitral valve murmurs before the age of 10. Whether that pedigree is a linebreeding or an outcross for me is less important. Outcrossing to a line with similar heart defects doesn't help me avoid heart defects very much. My pedigrees are less tight than they used to be, but I would still class many of my dogs as linebred.

For the most part, this scheme seems to be working. I have greatly reduced my incidence of Whippets who are showing up with heart murmurs at under the age of 10. I am hoping the research will provide further help. Cathie is right--heart disease at earlier ages is very devastating for the owner. Nobody wants to breed dogs who have heart problems.

Repeated inbreeding isn't good breeding practice, but I'll go back to what I said before...if the dog isn't able to win well at something, nobody cares about its COI, they aren't going to use it regardless. Breeders do look at phenotype, and the goal of doing some linebreeding is to insure that the phenotype that attracts other breeders to your dog or line is also the result of a genotype that will be consistently produced. Eceni--your positions are very orthodox veterinary positions but they do not take into account the "on the ground" realities that breeders face. We have to try to produce healthy stock. But we also have to maintain breed type and doing some tighter crosses to reinforce type characteristics are among the tools in a breeder's tool kit. Not all outcrosses turn out well enough to be useful, and not all tight breedings are callous or done without thought of genetic health.

A certain number of genetic defects are the price purebred dog/cat/sheep/fancy guppy breeders for working with a closed gene pool. Importing has been a very good way to increase heterozygousity at the genetic health level in the first generation or two, but crossing back onto imports has not been any more successful in producing no defects than crossing back into our own problem pools.

That being said, I wouldn't mind a cap on the number of litters a stud dog can sire in his lifetime. Surely after 10-15 litters, a good sire will have some sons worth using. We CAN do more. We CAN choose not to overuse certain popular sires. We CAN be more honest with each other and help new breeders not make crosses we feel based on our experience increase genetic risk (although some new breeders are mighty stubborn....I know when I was new I was! :- " )
 
If you are saying that not all diseases are recessive, then you could bring a disease into your line by outcrossing. That is the point that I was trying to make, that your line did not necessarily have a recessive gene for a health problem to develop. I do agree with Cathie that there definitely comes a time when you are line breeding that you need to go out. However, I do not think that the demon here is just line breeding. You can have a healthy breeding program if you are staying within your line whilst breeding only from stock that are known (or as far as you can know) to be healthy. Face it, any breeding is taking a chance at what you will produce.

Again, as many have said, HONESTY is the way forward. With this honesty, we all have to not blame other people's dogs or bitches for producing problems. As long as any of us do, we can't expect people to be open about the situation. It would take a very courageous person to set oneself up for the ridicule.
 
Eceni said:
clayelem said:
My parents were complete outcrosses.  My mother's family produces diabetes ,which is an inherited disease, no matter who they are coupled with.  If diseases are recessive genes, how do you explain this?  My father's family and the families who my mother's siblings married into had no diabetic history.  Maybe they were carriers, but all nine families?  I don't think so.    After all, it happens with humans and our gene pool is a whole lot more diverse.  So are we sure that outcrosses don't bring problems into our lines?
Click to expand...

not all diseases are recessive. If your mother's family produces diabetes regardless of the outcross, then that form of diabetes is dominant by definition

but if your mother were a whippet, you wouldn't breed from her

we're assuming responsible breeding, which means you're not breeding with obviously affected animals, so by definition, the diseases that arise are recessive.

to put it more simply (I am trying, honest), if you cross your whippet with a GSD, you'll get a dog with a degree of hip dysplasia - which is why you wouldn't do that.

conversely, if you cross your whippet with an apparently normal border collie which carries Collie Eye Anomaly as a recessive, the offspring my carry the gene. You won't see it until several line-bred generations (it could easily take 9 - all these things are a roll of a dice) until you see CAE in this 'line.

numbers are complicated. There's a brilliant book on horse genetics where the author had a mare she thought was homozygous for non-bay (she was a chestnut but bay is a modifier). It took 10 matings of this horse to the same black stallion to get a bay colt proving she was a carrier of the bay modifier gene. This is a gene that's a simple autosomal - so each foal had a 50% chance of it being bay. SO the odds were long, but not too long

that's why test matings of stallions are so much easier than mares. At least bitches have multiple litters...

make sense?

m

Click to expand...

I am shocked! to me 10 foalings is bit much for any mare, I would never cover any of my mares that much in their lifetimes.
 
dragonfly said:
Here is another inherited condition that is becoming more common and is extremely disabling although not life threatening. It is a terrible blow to anyone who has a pet and can no longer enjoy a daily walk.
The condition is.....Corns

It may seem a small thing, until you have it. I was speaking to somebody the other day who was in despair over the condition of her dogs health.

Cathie

Click to expand...
Hi Cathie, my Blue Magpie had corns, I had them removed and tested, they are a form of wart, a virus, I would never put a dog through that again. He was in so much pain poor dog. Fred Hancock from St Austell had Spyanfly Stroller, he developed on on his front foot, a daughter of Blue Magpie got one, but apart from them, I know of no one else from then with the problem.

My vet said as they were caused by a virus curing them was very difficult. I don't think it has anything to do with autoimmune mediated problems. Greyhounds get them too, I think it is just bad luck.
 
I think it does, my Fiona she has Auto Inmune, and very 'corned' feet. She is on steroids which reduces it, but when you lower the dosage the corns come back worse !
 
Eceni said:
UKUSA said:
This is all very interesting and certainly a lot of food for thought. Ive been breeding dogs for thirty  years and its true you never stop learning and nor should you and ofcourse in aperfect world breeders would happily turn their pedigree's over for examination and information that would help "them", us, avoid health pitfalls . That however is not going to happen so for the time being we have to rely on each others honesty.Nicky

Click to expand...

Ok, I do know nothing at all about the politics of dog breeding, but I have been browsing happily on the Whippet Archive for the past few days...

if the pedigrees are on there, are they not in the public domain? Is there a secret stash of whippet pedigrees somewhere? (Or all other breed pedigrees?)??

confused now

not that it matters - it would take a concerted will by the overwhelming majority of breeders to change the system before something could be done...

but I really would like a whippet. I've had a lurcher and she was lovely... but whippets seem like a step forward, not back. Just that I want one that'll be healthy (and guaranteed to win at agility, of course... :)

m

Click to expand...
I am sure that someone will correct me if I am wrong but I was under the impression that the pedigrees published on the Whippet Archives have been published without owners permission or is that another site?

Nicky
 
All whippets are already related because they all have Ch Wingedfoot Marksman

or Laguna Ligonier on there pedigree and most of them will have both :)
 
I am shocked! to me 10 foalings is bit much for any mare, I would never cover any of my mares that much in their lifetimes.
Click to expand...

Don't ever come to Newmarket....

m
 
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UKUSA said:
Eceni said:
UKUSA said:
This is all very interesting and certainly a lot of food for thought. Ive been breeding dogs for thirty  years and its true you never stop learning and nor should you and ofcourse in aperfect world breeders would happily turn their pedigree's over for examination and information that would help "them", us, avoid health pitfalls . That however is not going to happen so for the time being we have to rely on each others honesty.Nicky

Click to expand...

Ok, I do know nothing at all about the politics of dog breeding, but I have been browsing happily on the Whippet Archive for the past few days...

if the pedigrees are on there, are they not in the public domain? Is there a secret stash of whippet pedigrees somewhere? (Or all other breed pedigrees?)??

confused now

not that it matters - it would take a concerted will by the overwhelming majority of breeders to change the system before something could be done...

but I really would like a whippet. I've had a lurcher and she was lovely... but whippets seem like a step forward, not back. Just that I want one that'll be healthy (and guaranteed to win at agility, of course... :)

m

Click to expand...
I am sure that someone will correct me if I am wrong but I was under the impression that the pedigrees published on the Whippet Archives have been published without owners permission or is that another site?

Nicky

Click to expand...
Nicky, you are right. Anyone can add your dogs to the site without permission :thumbsup:
 
seaspot_run said:
That being said, I wouldn't mind a cap on the number of litters a stud dog can sire in his lifetime.  Surely after 10-15 litters, a good sire will have some sons worth using.  We CAN do more.  We CAN choose not to overuse certain popular sires.  We CAN be more honest with each other and help new breeders not make crosses we feel based on our experience increase genetic risk (although some new breeders are mighty stubborn....I know when I was new I was! :- " )
Click to expand...
You wouldn't like to move to the UK, I suppose? That's the most lucid, intelligent, believable response I've ever had to why people line breed... and if it's done like this, then I would entirely support it - I want beautiful, elegant whippets with neat ears as much as anyone else... I just also want to know I can make a friend for life and not spend half of that life treating inherited diseases.

thank you....

so now can we do what you said?

sounds perfect to me

m
 
A very interesting and difficult topic... For me - extremely interesting, as I am a genetisist and applying population genetics to dog breeding is one of my main interests.

Eceni, you asked about COI levels in well established lines. I don't have any regular data, but most dogs I have analysed from the lines bred for 20 or 30 years, in UK have COI somewhere between 20 and 30%, and the higher COI I have found was ca 46%, which is almost equal to full siblings mating (it's interesting that finding a dog with such tight pedigrees is quite uncommon in any other part of the world, despite the fact, that it is in UK where the most different lines and families exist). However, the dogs with similiar COI at the level of ca 25% can have huge differences in the number of ancestors in 10 generation pedigree. Some have as few as 190 dogs in 10 generations, while a full pedigree consists of 2047 dogs, ie they have less than 10% of genetic variability they could have. The other, with COI at the same level can have nearly 400 dogs. Most dogs from outcrosses have about 700-800 ancestors in 10 generations, I have never found one with more than 900, which is considered "much diversity".

I'm talking about COI calculated for 10 generations because in a breed quite large in numbers one can easily find a dog with COI close to 0 when calculated for 5 generations, but still very few ancestors in previous generations.

The risk of intensive linebreeding isn't only about increasing chances for recessive diseases, but also about decreasing genetic diversity. And the later has very much to do with immune system and its reactions to infections. What is the worse - that if you loose some parts of the gene pool, you can do nothing to retrieve it. And that is something which not only affects any current litter, but which affects a breed as a whole, every future generation.

I think that's a good reason for looking for other males than all the others are using on their bitches, for using not so famous sisters and brothers of top dogs, if good enough to be bred from, for using forgotten studs in their veteran years (when most of the health problems had time to reveal) instead of current 2 y.o. top winner. Of course, I wholeheartly agree with Karen saying that the dogs must be good at something, and I am far from saying that this should be the only things to consider when choosing a breeding pair. But there are so many breeders, some of them even quite famous, who just use current top winner, without paying attention to anything else.
 
dolly said:
I think it does, my Fiona she has Auto Inmune, and very 'corned' feet. She is on steroids which reduces it, but when you lower the dosage the corns come back worse !
Click to expand...
Sorry to disagree, your bitch cannot have Auto Imune! She must have a auto immune mediated problem, Sadly it is too long ago for my vet to still have magpies records, the histology came back as plantar warts, similar to verrucas and virtually impossible to get rid of. I presume if your Fiona has a low immune system she will succumb to these things. :ermm:
 
Natalia said:
A very interesting and difficult topic... For me - extremely interesting, as I am a genetisist and applying population genetics to dog breeding is one of my main interests.

The risk of intensive linebreeding isn't only about increasing chances for recessive diseases, but also about decreasing genetic diversity. And the later has very much to do with immune system and its reactions to infections. What is the worse - that if you loose some parts of the gene pool, you can do nothing to retrieve it. And that is something which not only affects any current litter, but which affects a breed as a whole, every future generation.

I think that's a good reason for looking for other males than all the others are using on their bitches, for using not so famous sisters and brothers of top dogs, if good enough to be bred from, for using forgotten studs in their veteran years (when most of the health problems had time to reveal) instead of current 2 y.o. top winner. Of course, I wholeheartly agree with Karen saying that the dogs must be good at something, and I am far from saying that this should be the only things to consider when choosing a breeding pair. But there are so many breeders, some of them even quite famous, who just use current top winner, without paying attention to anything else.

Click to expand...
Thank you so very much. I can't begin to tell you what a relief it is to have a real geneticist with real figures at her finger tips and strong science in the background.

so perhaps now if we've established the need for genetic diversity, we can begin to establish how to do that?

thank you hugely. If there were a 'relieved and delighted' icon, I'd use it.

Manda Scott
 
Hi all

Karen, your last post was absolutely terrific. An explanation and reasoning that all of us can understand without having to be geneticists ourselves. Thank you so much.

Carol
 
Eceni said:
I am shocked! to me 10 foalings is bit much for any mare, I would never cover any of my mares that much in their lifetimes.

Click to expand...

Don't ever come to Newmarket....

m

Click to expand...
Sorry,I was assuming that you were talking about the "hobby" breeder & not the bloodstock breeder,I know all about the amount of times a mare is or can be covered when you are relating to racehorses...it is TB's that we breed too,but I can never get my head around taking that many foals out of one mare in her lifetime (especially with the poor sucess rate in breeding for racing),I know a lot of other bloodstock breeders have no problems with it but it is just my preference.

Sorry to digress from this very interesting ,though sometimes hard going thread.
 
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