The breeding of pedigree dogs has resulted in the production of mutant variant of dogs whose phenotype is very distant from the wild type (the wolf, Canis lupus).
These days a pedigree is often a guarantee that a dog will develop certain diseases or problems during the course of its life. Certain breeds will be beset by so many health problems that they will cost their owner a significant amount in veterinary bills and medications. And what about the dog itself, who was bred for a lifetime of suffering ? The BBC documentary "Pedigree dogs exposed" has discussed this problem.
Unfortunately the breeding of dogs has resulted in a genetic mess, due to poor breeding practices. In the course of breeding dogs, sooner or later genetic anomalies will appear. This happens all the time. What the breeder does when faced with a genetic anomaly is what determines the future of the breed. If the breeder chooses to ignore the problem and continues breeding the dog, then the anomaly will spread. Often breeders are selecting for a specific trait which they deem desirable, but if this trait is associated with an anomaly then this will be selected for too. You always get what you select for. It may not be what you want, but you always get what you select for! Some breeds have been selected for the sloping back trait. Little did they know that the sloping back was associated with hip dysplasia and spinal stenosis. By selecting for the sloping back, they also selected for hip dysplasia and spinal stenosis. Anyone looking at a wolf can easily tell that the hind legs and the croup are set at a slightly higher level than the front legs and the shoulder. This is the way mother nature designed the wolf. But these domestic dogs are built just the opposite (high in the front and low in the back) of how nature designed the wolf. No wonder the spine and the hips of these dogs are plagued with orthopedic problems. This is an example of a breeding strategy that makes no sense.
Some of the existing dog breeds are so plagued by genetic disease that it does not make sense to "salvage" them. Breed associations are scrambling to find genetic tests that will allow them to purge their breeds of the numerous genetic conditions with which they are afflicted. The main value of such an effort is to advance our scientific understanding of gene function and gene regulation and should probably be undertaken by universities. Ordinary dog owners will not benefit from these efforts, if their goal is to own a healthy dog which will not cost them a fortune in medical expenses. A smart breeding strategy to correct the problem of kidney stones in the Dalmatian breed has been devised bythe Dalmatian-Pointer backcross project.
Dalmatians can suffer from hyperuricemia. Uric acid can also be excreted in high concentration into the urine causing kidney and bladder stones to form. These conditions are most likely to occur in middle-aged males. To reduce the risk of gout and stones, owners should carefully limit the intake of purines by avoiding giving their dogs food containing organ meats, animal byproducts, or other high-purine ingredients. Hyperuricemia in Dalmatians responds to treatment with orgotein, the veterinary formulation of the antioxidant enzyme superoxide dismutase.
Hyperuricemia in Dalmatians (as in all breeds) is inherited, but unlike other breeds, the "normal" gene for uricase is not present in the breed's gene pool. Therefore, there is no possibility of eliminating hyperuricemia among pure-bred Dalmatians. The only possible solution to this problem must then be crossing Dalmatians with other breeds to reintroduce the "normal" uricase gene. This led to the foundation of the Dalmatian-Pointer Backcross Project, which aims to reintroduce the normal uricase gene into the Dalmatian breed. The backcross used a single English Pointer. Subsequent breedings have all been to purebred Dalmatians. This project was started in 1973 by Dr. Robert Schaible. The first cross (F1) hybrids did not resemble Dalmatians very closely. The F1s were then crossed back to purebreds. This breeding produced puppies of closer resemblance to the pure Dalmatian. By the fifth generation in 1981, they resembled purebreds so much, Dr. Schaible convinced the AKC to allow two of the hybrids to be registered as purebreds.
The Dalmatian Heritage Project began in 2005. The goal of the project is to preserve and improve the Dalmatian breed by breeding parent dogs with the following traits:
All puppies in the Heritage Project are descendants of Dr. Robert Schaible's parent line. Today, "Dr. Schaible’s line produces the only Dalmatians in the world today that are free of a metabolic defect that can lead to urinary tract problems.
This strategy makes lots of sense. If you use just one dog in a population of 100,000 dogs you will not alter the appearance of the breed and yet you can introduce a healthy gene and over the years spread it through the population. This is one way to "fix" a genetic defect in a breed and shoud be an example for other breed societies.
Most breeds were established using a very small number of founder dogs. Often less than ten founding dogs. Screening out lots of dogs will simply reduce the gene pool even further, therefore increasing inbreeding. It is not going to work in terms of "salvaging" the breed. What needs to be done is to introduce a very small number of new dogs into to the breed, carrying the healthy alleles of the genes of interest. Most of today's popular breeds are doomed to extinction if such salvage measures are not taken. Soon dog owners will realize that they are spending a fortune on the medical care of their dogs. they will do the sensible thing, and choose a different breed when they buy their replacement puppy. At the same time "reputable" breeders continue to sell dogs programmed to develop certain medical conditions to the general public. Breeders of certain dog breeds will not be able to honor the guarantees they make to buyers at the time of sale of a puppy. If they replace a puppy because of disease, the replacement puppy also will develop problems. The outcome will be that certain breeds will rapidly decline in popularity and eventually disappear. People are moving away from puredbred dogs because of all the genetic diseases and moving towards the so called "Designer Dogs" (like Labradoodle, Goldendoodle and Cockapoo) in which the hybrid vigour of the F1 generation masks the genetic conditions of which the dogs are still carriers.
Fortunately, there are some breeds that are still relatively problems-free. (Please note that this is just my opinion. Doyour own research before acquiring a new puppy and do not rely solely on this list. I compiled this list based on information avalaible to me as of late 2013, and this information may change.)
The reason these breeds avoided many genetic diseases is that they were either
1) a landrace, more than a breed, which developed only partially under the effect of selection operated by humans
2) derived from a rather large number of founding specimens
3) derived from a small number of founders, but were "lucky" since the founders transmitted only a small number of genetic defects and human selection did not introduce any new genetic faults (which could however still be introduced in the future by poor breeding practices).
We consider these breeds "healthy" (meaning that the roportion of dogs with genetic diseases is less in these breeds, however the possiblity of picking a dog that will develop genetic disease(s) is not zero) :
1) Akbash Dog
10) Beagle Harrier
11) Black Mouth Cur
12) Blue Lacy
15) Can De Palleiro
16) Canadian Eskimo Dog (the breed was founded with more than 200 specimens)
17) Cane Corso Italiano (but not the American Cane Corso)
22) Dogo Sardo
23) Dutch Shepherd
25) European Laika
26) Galgo Espanol
28) German Pinscher
33) Greenland Dog
36) Hanover Hound
42) Leavitt Bulldog
43) Lupo Italiano
48) Pastore Italiano
50) Perro Lobo Espanol
53) Plott Hound
55) Pyrenean Mastiff
56) Segugio Italiano
57) Segugio Maremmano(the breed was founded with 6,000 individuals)
59) Serbian Hound
60) Siberian Husky