There is a lot of discussion about the importance of health testing on the part of both breeders and consumers. Should we assume it's always a good thing, or are there considerations not readily apparent.? It certainly sounds important, and a website with lots of medical lingo can appear to represent breeders who are very knowledgeable and ethical in their breeding practices and who raise perhaps a healthier puppy. However, while we do test at Hurricane Creek Poodles and Doodles, there are some issues on the subject and some tests that are done that provide a false sense of security and perhaps produce the opposite of our desired effect.
In recent years, the discovery of identical twins who were separated at birth, has provided the substrate for some very enlightening studies by both sides of the "Nurture or Nature" question. Studies of identical twins who have grown up separately on different sides of the continent, or in some cases different sides of the globe, have suggested that numerous individual characteristics are programmed into our genetic code. Identical twin brothers, who were separated at birth and re-united 30 to 40 years later, had both chosen to become firemen, were both a little rounded about the middle, and were both bald. The similar pattern of hair loss might have been anticipated, but the choice of career, not so much. Another set of identical twins met as adults and found they both chain smoked the same brand of cigarettes, both liked the same beer, both suffered from migraine headaches, both had a wood working shop in their garage and both had been married twice, first to a Linda and then to a Betty! Studies of identical twins raised in different environments suggest that DNA plays a VERY strong role in determining the type of person, OR DOG, an individual becomes, both physically and emotionally.
There are now tests available for several genetic diseases or condtions that can absolutely rule out any risk of contracting a specific disease or condition. If a dog does not have the DNA for Von Willebrand's disease, a bleeding disorder, it will not get the disease. In the same manner, a peron who does not have the DNA for sickle cell anemia, will never develop a sickle cell, that is a collapsed or lopsided blood cell, or have that specific kind of anemia. However, if we had the power to preclude all reproduction by people with the DNA to produce a sickled cell, many more people would have died from Malaria, as only one gene for sickle cell anemia produces blood with some normal cells and some collapsed cells, and for unknown reasons, provides a level of protection from Malaria. Elimination of certain individuals from a breeding population can be an excellent idea, especailly if they carry the DNA for a life threatening or life disabling condition. However, that elimination also shrinks the overall gene pool from which our dogs can draw their DNA. If we had a dog who tested DNA positive for a life threatening illness, we would not use that dog for breeding. DNA testing reveals a coding sequence that directs the production of certain desirable or undesirable proteins in the dog's DNA. It is a very specific test and can protect dogs, breeders and consumers from some heart breaking illnesses. However, other testing is less specific and less beneficial. A dog with wonderful hips, as determined by x-ray and not genetic testing, can produce a dog with undesirable hips. A dog with perfect eyes in the spring of 2015, might have problematic eyes when examined in the fall of 2016. What of the puppies born during the interim?
What can we conclude from these random observations? DNA testing can give us conclusive results as regards SOME genetic conditions. That is not to say that DNA is not always reliable. It is, despite the naysayers' pointing to the only 99.97% acurracy. However, numerous genetic conditions have not yet yielded their secrets to the scientific community. If they are not yet sequenced or not yet identified through electrophoresis, we cannot begin to elimitate them from the population, especially if they are homozygous recessive conditions, meaning they can be carried or hidden for multiple generations. Further more, attempts to elliminate traits considered less than optimum, can have the negative effect of shrinking the gene pool and therefore concnetrating the occurance of as yet undetected problems. Negative health tests can provide guarantees against some conditions, but not all, and can in fact, increase the likelihood of others we may not yet have discovered. We must be careful in our financial support and patronage of testing laboratories and consider the risk versus benefit to our dogs, our breeding programs and our customers. The elevated cost that we pass on to the buying public from tests must represent improved health and not just expansion and financial support of testing laboratories to provide a false sense of security to the consumer. This comment should in no way be considered a disparaging remark as regards labs, only a caution to test wisely and not raise our prices sky high without benefit to the final product: a happy and healthy puppy.
What about hips?
Research was done in 2006 by a group of veterinarians, including Gail K. Smith, VMD, PhD; Erin R. Paster, DVM; Michelle Y. Powers, DVM; Dennis F. Lawler, DVM; Darryl N. Biery, DVM, DACVR; Frances S. Shofer, PhD; Pamela J. McKelvie, VMD; Richard D. Kealy, PhD. Their goal was to evaluate the effects of diet restriction on the deveopment of arthritis in the hips of dogs. The study was done on labs and the results measured by X-rays. They found two interesting facts: dogs on a restricted diet had a lower incidence of osteoarthritis in terms of both severity and age at onset, and, at least for the labs involved in the test, arthritis progressed with age, no surprise there, and that dogs free of the condition at age two did not neccessarily remain free from the condition. Earlier studies done by Jessen and Spurrell suggested that dogs did not get chronic hip disease after two years of age. However, this study suggested that "Hip phenotype can change markedly (from normal to abnormal) after 2 years of age. Breeds of dogs with high susceptibility to CHD should be kept lean for life, and dogs selected for breeding should have radiographic hip evaluations at regular intervals throughout life. We suggest that more exacting methods than use of the hip phenotype obtained from the standard hip-extended radiographic view should be used for selection of breeding."
What does all that scientific gibberish mean? Radiographic testing of dog's hips is not a reliable indication of whether or not a dog, much less its offspring, will have hip dysplasia, AND, restricting feeding can ensure a delay in disease onset and lessening of its severity.
for more information on hip dysplasia, see the follwoing article: