Joined
·
8,689 Posts
The Secrecy of Defects In Dogs
By: George A. Padgett, DVM
Professor in the Department of Pathology, College of Veterinary Medicine at Michigan State University The first and major hindrance to recognizing the significance and cost of genetic disease is that most breeders believe that the MAJORITY OF DOGS ARE GENETICALLY NORMAL. This is not the case at all. Aside from what is likely to be the case, if you believe most dogs are genetically normal and you find out your dog carries a defect, whether it's cataracts or something else, you do not want to talk about it because you believe your dog is different (less worthwhile) than MOST dogs.
The average for genetic defects in any breed is about 14.
This belief causes a person to be secretive about a trait, to deny that it occurs, and, as a result, to fail to
address the defective gene as a problem which can be solved.
It is difficult to convince breeders that ALL dogs carry defective genes because people tend to hide problems and thus they are not an obvious part of the productivity of a dog or a kennel. However, the elite of the breed, the superior dogs, those that contribute a disproportionately high number of genes to the gene pool of the breed, allow us to get a better look at the problem for two major reasons.
• The first is that a good stud is used on bitches outside the control of the owner of the stud and thus the offspring of the stud are observed by multiple people and with multiple people it's hard to keep a secret. As a result, GOSSIP occurs. It may be true (also may not) but it's treated as gossip and sort of whispered rather than being openly discussed. Alternatively, a stud of lesser quality and not as well used, producing, say, two litters, may well have expressed the identical gene but the gossip is controlled (only two breeders are involved).
• The second reason relates directly to the first. For a genetic disease to exist in a breed, there must be affected dogs, carrier dogs (those having one gene for the trait), and dogs normal for both genes existing within the populations. Obviously, a dog bred more widely has a better chance to contact a carrier bitch and thus give the trait a better chance to express itself than a dog that produces one or two litters, even though both dogs are themselves carriers [controlled test matings may be the only way to establish who's who].
As a result of these two major features of genetic diseases and dog breeders (odds of producing a defect and gossip), you cannot name a single major dog in my breed that has produced 200 puppies or better (40 litters, 5 per litter) that has not produced some defect (try it, see if you can think of one). Further, once you know the dog has produced a recessive defect, then you know that each of his puppies has a 50:50 chance of being a carrier for that defect whether the puppy was born before the stud produced the defect or after he produced it.
What breeders most often forget, however, is that the reason you know a superior dog has a defect is that the dog is in fact superior. He is used more often than dogs of lesser status because he produces winning offspring. He adds quality to the breed or he would not have been allowed to produce so many puppies (remember, this is controlled by the owners of the bitches, not the owner of the stud). WE now have 200 puppies on the ground, many of which are already champions (or you wouldn't have 200 puppies on the ground!), half of which are carriers. The owners of these dogs have already made a large investment in them and now they do not want to talk about any defects involving their dogs. What I call "THE CODE OF SILENCE" is imposed; it is unethical to talk about defects, owners that talk about defects are thought of as abhorrent. Breeders that admit their dogs have or carry a defect are hounded by others no matter what quality the dog nor how healthy the dog. The stage is set for what breeders do best to one another: THEY LIE TO EACH OTHER or they evade or they do not involve themselves in "useless" discussions or they fib or they do anything they can to avoid the fact that THEIR dog carries a gene for a given defect or may in fact have the defect (if it cannot be observed without special techniques).
This is the dilemma that dog breeders face no matter what the breed, no matter how famous the dog. ALL DOGS HAVE DEFECTIVE GENES LIKE ALL PEOPLE HAVE DEFECTIVE GENES. The question now becomes what should you do about it and what can you do about it?
Dog breeders in general ... cause defective genes to spread within a breed by failing to approach genetic defects in an open manner. They control the matings of their dogs, but somehow they end up expecting "nature" to correct defects in the same manner natural selection works in a wild population. If "nature" bred their dogs there might be some basis for the belief that a disease such as cataracts might be corrected over a period of one or two hundred years by natural selection. The fact that none of the breeders (having the belief that natural selection is protecting them) would be alive when it happened doesn't seem to faze them.
TRAIT'S WILL NOT DISAPPEAR BY THEMSELVES. NATURE WILL NOT SAVE YOU BECAUSE NATURAL SELECTION HAS NOTHING TO DO WITH DOG BREEDING.
Dog breeders in general need to face genetic defects as a realistic part of the problems encountered in the process of producing good sound animals. We need to quit whispering about defects and gossiping about defects and instead set up a sound program that allows the standard selection procedures to go on so that we breed good dogs and avoid major defects.
A decision needs to be made so that you can control what you have, breed it out or spread it.
Disclaimer: The NRTA is posting this article for information purposes only. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~
Solving the Problems and the Painful Truths
There is no easy answer to get rid of defects in dogs. Remember most dogs carry 14 disease/defective traits that may come up in your breeding program at some point.
Most defects are recessive in nature meaning that both parents are carrying the gene and will produce the problem. Some however are not recessive in nature and only one parent needs to be carrying the gene in order to produce it. Lastly some defects are a combination of environmental issues and nutritional issues alone where neither of the parents are responsible for the defect. Unfortunately a lot of diseases have not been studied in dogs to be sure what exactly the genetic inheritance of the particular problem is.
Here are some examples.
Hip Dysplasia is one of them. Some experts say its genetic while others say it's due to early injury and still others theorize that it's a combination of nutrition and environmental factors.
The general consensus on Patella Luxation and Legge Perthes has been assumed that it is recessive in nature and that in order to produce a pup with the problem both parents must be carrying it.
Demodectic Mange is a great one under controversy. Since all dogs have the mites on them from birth it can be rather hard to determine if the pup breaks out because of stressful conditions or if there immune system has not fully matured yet or if its strictly genetic.
Under or Over shot jaws can be caused by genetics or by breeding two dogs with dissimilar head shapes. Meaning one dog has a long muzzle and the other parent has a short muzzle. The upper and lower jaws grow at different rates so that if a puppy has a good bite when very young and suddenly goes over or under there is a chance that the bite will self correct once the jaws catch up with each other. That is not always the case though.
The list goes on and on with defects but two healthy dogs that have been bred several times without occurrence of problems can suddenly produce a defect that shows up.
If you breed a male and a female and come up with defects then you can not always be sure that both of the parents are carriers when they do not express the defect themselves because of the lack of information on genetic inheritance modes. Generally speaking though, if both parents are carrying a bad recessive trait, a quarter of there offspring will show the defect, half will be carriers and a quarter will be free of the problem. It is now impossible to say which offspring are carriers and which are free of the defect. The affected ones are obvious.
By: George A. Padgett, DVM
Professor in the Department of Pathology, College of Veterinary Medicine at Michigan State University The first and major hindrance to recognizing the significance and cost of genetic disease is that most breeders believe that the MAJORITY OF DOGS ARE GENETICALLY NORMAL. This is not the case at all. Aside from what is likely to be the case, if you believe most dogs are genetically normal and you find out your dog carries a defect, whether it's cataracts or something else, you do not want to talk about it because you believe your dog is different (less worthwhile) than MOST dogs.
The average for genetic defects in any breed is about 14.
This belief causes a person to be secretive about a trait, to deny that it occurs, and, as a result, to fail to
address the defective gene as a problem which can be solved.
It is difficult to convince breeders that ALL dogs carry defective genes because people tend to hide problems and thus they are not an obvious part of the productivity of a dog or a kennel. However, the elite of the breed, the superior dogs, those that contribute a disproportionately high number of genes to the gene pool of the breed, allow us to get a better look at the problem for two major reasons.
• The first is that a good stud is used on bitches outside the control of the owner of the stud and thus the offspring of the stud are observed by multiple people and with multiple people it's hard to keep a secret. As a result, GOSSIP occurs. It may be true (also may not) but it's treated as gossip and sort of whispered rather than being openly discussed. Alternatively, a stud of lesser quality and not as well used, producing, say, two litters, may well have expressed the identical gene but the gossip is controlled (only two breeders are involved).
• The second reason relates directly to the first. For a genetic disease to exist in a breed, there must be affected dogs, carrier dogs (those having one gene for the trait), and dogs normal for both genes existing within the populations. Obviously, a dog bred more widely has a better chance to contact a carrier bitch and thus give the trait a better chance to express itself than a dog that produces one or two litters, even though both dogs are themselves carriers [controlled test matings may be the only way to establish who's who].
As a result of these two major features of genetic diseases and dog breeders (odds of producing a defect and gossip), you cannot name a single major dog in my breed that has produced 200 puppies or better (40 litters, 5 per litter) that has not produced some defect (try it, see if you can think of one). Further, once you know the dog has produced a recessive defect, then you know that each of his puppies has a 50:50 chance of being a carrier for that defect whether the puppy was born before the stud produced the defect or after he produced it.
What breeders most often forget, however, is that the reason you know a superior dog has a defect is that the dog is in fact superior. He is used more often than dogs of lesser status because he produces winning offspring. He adds quality to the breed or he would not have been allowed to produce so many puppies (remember, this is controlled by the owners of the bitches, not the owner of the stud). WE now have 200 puppies on the ground, many of which are already champions (or you wouldn't have 200 puppies on the ground!), half of which are carriers. The owners of these dogs have already made a large investment in them and now they do not want to talk about any defects involving their dogs. What I call "THE CODE OF SILENCE" is imposed; it is unethical to talk about defects, owners that talk about defects are thought of as abhorrent. Breeders that admit their dogs have or carry a defect are hounded by others no matter what quality the dog nor how healthy the dog. The stage is set for what breeders do best to one another: THEY LIE TO EACH OTHER or they evade or they do not involve themselves in "useless" discussions or they fib or they do anything they can to avoid the fact that THEIR dog carries a gene for a given defect or may in fact have the defect (if it cannot be observed without special techniques).
This is the dilemma that dog breeders face no matter what the breed, no matter how famous the dog. ALL DOGS HAVE DEFECTIVE GENES LIKE ALL PEOPLE HAVE DEFECTIVE GENES. The question now becomes what should you do about it and what can you do about it?
Dog breeders in general ... cause defective genes to spread within a breed by failing to approach genetic defects in an open manner. They control the matings of their dogs, but somehow they end up expecting "nature" to correct defects in the same manner natural selection works in a wild population. If "nature" bred their dogs there might be some basis for the belief that a disease such as cataracts might be corrected over a period of one or two hundred years by natural selection. The fact that none of the breeders (having the belief that natural selection is protecting them) would be alive when it happened doesn't seem to faze them.
TRAIT'S WILL NOT DISAPPEAR BY THEMSELVES. NATURE WILL NOT SAVE YOU BECAUSE NATURAL SELECTION HAS NOTHING TO DO WITH DOG BREEDING.
Dog breeders in general need to face genetic defects as a realistic part of the problems encountered in the process of producing good sound animals. We need to quit whispering about defects and gossiping about defects and instead set up a sound program that allows the standard selection procedures to go on so that we breed good dogs and avoid major defects.
A decision needs to be made so that you can control what you have, breed it out or spread it.
Disclaimer: The NRTA is posting this article for information purposes only. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~
Solving the Problems and the Painful Truths
There is no easy answer to get rid of defects in dogs. Remember most dogs carry 14 disease/defective traits that may come up in your breeding program at some point.
Most defects are recessive in nature meaning that both parents are carrying the gene and will produce the problem. Some however are not recessive in nature and only one parent needs to be carrying the gene in order to produce it. Lastly some defects are a combination of environmental issues and nutritional issues alone where neither of the parents are responsible for the defect. Unfortunately a lot of diseases have not been studied in dogs to be sure what exactly the genetic inheritance of the particular problem is.
Here are some examples.
Hip Dysplasia is one of them. Some experts say its genetic while others say it's due to early injury and still others theorize that it's a combination of nutrition and environmental factors.
The general consensus on Patella Luxation and Legge Perthes has been assumed that it is recessive in nature and that in order to produce a pup with the problem both parents must be carrying it.
Demodectic Mange is a great one under controversy. Since all dogs have the mites on them from birth it can be rather hard to determine if the pup breaks out because of stressful conditions or if there immune system has not fully matured yet or if its strictly genetic.
Under or Over shot jaws can be caused by genetics or by breeding two dogs with dissimilar head shapes. Meaning one dog has a long muzzle and the other parent has a short muzzle. The upper and lower jaws grow at different rates so that if a puppy has a good bite when very young and suddenly goes over or under there is a chance that the bite will self correct once the jaws catch up with each other. That is not always the case though.
The list goes on and on with defects but two healthy dogs that have been bred several times without occurrence of problems can suddenly produce a defect that shows up.
If you breed a male and a female and come up with defects then you can not always be sure that both of the parents are carriers when they do not express the defect themselves because of the lack of information on genetic inheritance modes. Generally speaking though, if both parents are carrying a bad recessive trait, a quarter of there offspring will show the defect, half will be carriers and a quarter will be free of the problem. It is now impossible to say which offspring are carriers and which are free of the defect. The affected ones are obvious.