Diminishing Doggie Disorders
She was the perfect family pet: a beautiful Border Collie named Shasta. The breeder informed us that Shasta’s purebred parents were not DNA tested for Hip Dysplasia, a common genetic disorder in Border Collies; but she reassured us by saying, “Don’t worry! No one has ever complained about one of my puppies having any defects!” So we purchased Shasta and later, without any thought of DNA testing her, bred her to a purebred Border Collie and had a litter of puppies. Around this time, Shasta went through a couple of strange accidents. She jumped for a ball and seemed to stumble on landing, limping and shaking with pain. We took her to the vet, but he found nothing noticeably wrong with her. After a few hours the pain passed and Shasta forgot all about her accident… that is, until it happened again with the same results.
Many purebred canines suffer from inbred genetic disorders such as hip and elbow dysplasia, eye diseases, glaucoma, heart diseases, and many others—some more native to certain breeds than others (Carricato, 1992). The dogs inflicted needlessly suffer, and many owners who are ignorant of the problem, as we were, go on to breed their dog and thus pass these genetic disorders on through more generations. There is a solution to the problem, however. If dogs would be DNA tested and cleared of any genetic disorders that their breed is prone to before being bred, then many disorders would be diminished instead of spread.
Striving to eliminate genetic dog disorders can be carried out in two steps. The first step should be taken by everyone who is buying a purebred puppy, even if that puppy is just a future family pet. These potential owners need to make sure to buy a puppy from breeders who have DNA tested and cleared their dogs for common genetic diseases. This is the easiest step in diminishing genetic diseases in dogs, but it does narrow the available field of puppies, as quite a few cheaply-priced dogs come from “backyard breeders” who failed to DNA test their dogs. The second step only needs to be carried out by those who are planning to breed their dog. These future breeders need to DNA test and clear their puppy, even if it comes from cleared parents. Although expensive, this crucial step will help ensure that the future puppies will not inherit any genetic disorders.
Some may wonder if this step is necessary when they have already purchased a puppy from tested and cleared parents. Pruka (2005), who breeds and shows Border Collies and is on the health committee chair for the BCSA (Border Collie Society of America), explained that because genetic diseases are caused by recessive genes, “both parents can be free from the disease but still produce carrier and affected offspring” (as cited in Darnell, 2005, p. 75). Consequently, puppies from already-tested parents need to be DNA tested and cleared as well to ensure that they do not carry and pass on any genetic diseases to more offspring.
Yet, as Pruka stated, there is always the possibility that even if both parents are tested and cleared of genetic disorders their puppies will still be carriers of the diseases. So why even try? Actually, this is the reason why DNA testing is so important. Just because there are possibilities of genetic diseases does not mean people should stop trying altogether. In fact, more precaution should be taken to combat the diseases. If generation after generation of dog owners become aware of the genetic diseases of purebreds, and purchase puppies from tested parents only, and then test and clear those puppies before ever breeding them, over time they will eliminate the diseases.
There are two popular methods of DNA testing that vary in cost and procedure. The OFA (Orthopedic Foundation for Animals) offers both of these methods through most veterinarians. The first method is to send in a cheek swab sample that is analyzed for the genetic disease, and the second is to evaluate X-rays for any sign of the genetic disease. The OFA (2010) showed that costs for either process range from between $30.00 to $60.00, although additional costs could be added by a veterinarian for the appointment or anesthesia during X-rays. That may seem expensive to some, especially when they consider the fact that both the male sire and all female dams should be tested. Yet, when compared to years of pain an afflicted dog may suffer—perhaps even dying at a young age—the price does not seem so high. Indeed, no price can be put on having a pet live a long and happy life.
Many people might argue that DNA testing shouldn’t be bothered with since genetic disorders do not always affect the dog until later in life, when they’re getting old anyway. In fact, some dogs may only be carriers of the genetic disease, and will never experience any adverse conditions from it. This is a valid argument for those who own a dog that is just a household pet. However, if a dog carriers a disorder, it will pass it on genetically to its offspring. In this case, all breeding needs to stop and the dog needs to be fixed, regardless of whether or not it is personally affected by the disorder.
Breeding mix-breeds instead of purebreds is another possible and effective solution to inbred genetic disorders. However, many people prefer the popular purebred breeds over mix-breed “mutts.” Meyers-Wallen (2003), an associate professor of genetics and reproduction at Cornell University, wrote that people may favor purebreds because their behavior and appearance are reasonably predictable. She stated that as long as the purebred breeds are desired by the public “it is reasonable for us as specialists in veterinary clinical reproduction to facilitate production of healthy purebred animals” (p. 73). DNA testing provides the solution that keeps the purebred breeds alive while continuing to eliminate the genetic disorders of inbreeding.
Some would argue that the best way to eliminate genetic diseases is by spaying and neutering all puppies before selling them so that their future owners cannot breed them. However, these individuals fail to remember exactly how puppies are brought into the world in the first place. Yes, they will eventually succeed in eradicating all genetic diseases, but in the process they will also eradicate dogs! Spaying and neutering have their place though, and should definitely be done if a dam or sire is found to be a carrier of a genetic disease.
This is what we had to do after we finally had our Border Collie’s hips X-rayed and examined by the OFA. We were shocked when the results showed that Shasta had a very bad case of hip dysplasia. This explained her two painful jumping accidents as a puppy, which had probably temporarily dislocated her hips. Since hip dysplasia is passed genetically from parent to offspring, we knew that we had to spay Shasta and could no longer enjoy raising her puppies. A now-retired, five-year-old mother dog, Shasta’s hip dysplasia rarely bothers her. But in her old age, this genetic disease will probably strike again, and we may have to lose our beautiful, loyal pet earlier than normal. Not only that, but without meaning to, we have passed this painful disease on to other puppies, other homes, and other families. If they choose to breed and have more puppies, the disease will be further spread, all because we failed to buy a puppy from DNA tested parents, and DNA test her before we bred her.
The passing of genetic diseases from generation to generation doesn’t have to happen to other dog owners and breeders. These painful genetic disorders among purebred dog breeds could eventually be eliminated if owners would buy puppies only from DNA tested and cleared parents, and always have their dogs DNA tested and cleared before breeding. Those who fail to spend a small amount of time and money to do this actually make their dog pay the price in pain later. And if they have bred their dog, then the genetic disorder has only been spread further, causing more pets and their owners to suffer. Those who do take heed and DNA test purebred dogs will diminish inbred genetic disorders. In doing so, they will preserve not only ancient and noble bloodlines, but also happy and healthy dogs.
References
Carricato, A. (1992). Veterinary notes for dog breeders. New York, NY: Howell.
Darnell, G. F. (2005). Herding group: Border Collies. AKC Gazette, 122(12), 75-76.
Meyers-Wallen, V. N. (2003). Ethics and genetic selection in purebred dogs. Reproduction in
Domestic Animals, 38(1), 73-76.
Orthopedic Foundation for Animals. (2010). OFA fee schedule. Retrieved from
http://www.offa.org/fees.html
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