There have been many books written about defects in dogs which are thought to be inherited. Some of these disorders have been proven to be inherited through research whereas others are thought to be inherited, yet there is no reliable data to verify this. 

It is a far common practice to talk about a disorder as being inherited when there is little or no proof to actually verify this 100 %. Accusations like this can be both dangerous and detrimental to both the dog in question as well as the breeder’s reputation. When a defect occurs in a dog one should not immediately jump to the conclusion that it is an inherited defect. There are numerous other causes that can lead to the defect in the dog(s) in question. Possibly something might have gone wrong during the pregnancy such as the administration of certain medication that might have caused the defect. Another cause could be of an acquired disease that caused the defect in the dog(s) during pregnancy and thus unrelated to a genetic defect. 

It is quite possible that more than one bitch in a breeder’s kennel may produce a defective puppy, but this should not cause one to assume that it is an inherited condition. Despite the fact that the bitches in question had similar pedigrees, one should also take into consideration that they also shared a similar environment and this could be the cause for the defect. One should follow a step by step investigation before determining whether the defect was of genetic origin or not as is illustrated in the step by step approach as indicated below. 

  1. Defect has occurred in the litter.
  2. Try to describe the defect as accurate as possible.
  3. Look up the problem in published veterinary literature and other (reliable) canine literature.
  4. If the problem has already been documented before then the veterinarian or breeder should provide breeding advice to both other breeders and the parent club involved. If possible set up a registry to record affected dogs and their parents to try to identify the carrier involved.
  5. If the problem has not been reported before, one should investigate the underlying cause.
  6. Determine if it is caused by genetics, medicine use, nutrition, or from a disease.
  7. Talk to other breeders of your own breed and other breeds as well as the breed club. Send out questionnaires to these groups.
  8. Repeat the mating to see if the defect reoccurs. 

When trying to find the problem of the defect one should try to be as descriptive as possible. It is not sufficient to report to the breed club that a litter has eye, heart, or liver problems as these terms are vague when considering that there are many such problems in dogs. The best method is to consult veterinary advice for the necessary tests.

This usually means common tests like blood tests, x-rays, and ophthalmology examinations as well as possible biochemical analysis. Ideally the help of a specialist from a veterinary faculty will also be of great help. 

If a genetic disorder is thought to be the cause then veterinary journals can be a good starting point in finding the underlying cause. Veterinary journals only contain articles that have been approved by a scientific committee to be published. This means that statistics have been applied. Statistics is a mathematical equation used to determine as to how accurate the obtained results were and as to whether there is a relationship with as to the “suspected” cause of the problem.” Not every article can be published; it has to pass a long list of criteria before it is approved to be published.  

Examination of the defect in question in other species can also be helpful in understanding the problem better. It is also quite possible that the defect is an inherited disorder and already reported in another breed other than one’s own. 

It is also possible that the defect is actually entirely new in the canine population which means that one has to determine whether it is caused by a diet related factor, a disease, an infection or from a fault in the manufacturing of the dog food. Some problems can also occur during a certain point in the pregnancy of the bitch when certain body organs are being formed. Determining what the cause is may not be easy but if a non-genetic cause is suspected then the positive point is that a breeder’s reputation is not destroyed and that valuable breeding animals are not culled from the breeding program. 

When a genetic cause is suspected one needs to collect as much data as possible. This can be done through the breed club by sending out a detailed questionnaire to it’s members. It would also be advisable to send such a questionnaire to other breed clubs in other countries to determine how far spread the problem actually is. It is in the benefit of the breed as a whole that all breeders and clubs collaborate together to solve this problem instead of only a few who admit that they have the problem in their kennel. 

It is not sufficient enough to just collect pedigrees of the affected dogs. Rather one has to also collect data on the number of pups affected in each litter, the sex of the pups affected, age of onset, and any variations in the defect. Such data could help determine the mode of inheritance of the defect in question. 

Far too often breeders with an access to only a small limited supply of pedigrees of affected dogs are far too eager to label a certain male dog appearing frequently in the pedigree as being the carrier of the defect. One might be correct but there could be more factors involved. The source might also be a female or the carrier might be farther back in the pedigree than the normal 5 generation pedigree indicates. The dog labeled by the breeders may not only appear in all of the affected pedigrees but also in the unaffected ones because he was one of the founding sires of the breed. 

Behaviour disorders are even more difficult to determine as being of a genetic disorder or not because the socialization and upbringing of a dog are also important. Not every owner is as experienced with raising a puppy or as dedicated to their pet as one would hope. These factors are difficult to tabulate and there is a large error margin involved. 

To determine and label a defect as being of genetic origin without sufficient proof is practiced far too often in the dog world. It in turn can do untold harm to the breed as a whole but also the dog involved. Such a breeder who has dedicated a large portion of his/her life can have their reputation quickly destroyed by circulating rumors that have no valid facts to support them.

 

Bibliography:

 

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10. Pedigree dynamics & Jane Henning Bloodstock. Cheating at Genetic Loto

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12. Roslin Williams, M. Reaching For The Stars.Doral Publishing, United Kingdom 2000.  P. 61 – 72, 87 – 95.

 

13.                       Russell, P. Genetics (4th Edition). Harper Collins College Publishers 1996.p. 9 – 12, 18 – 39, 66 – 87, 100 – 102, 134 – 140 695 – 707

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15.                       Ting, B & G. Labrador Stammbaumbuch 1997. Digital Print, Germany p. 1 -121.

16.                       Wikipedia encyclopedis http://en.wikipedia.org/wiki/X_chromosome