Canine Hip Dysplasia

Lately I have been further researching Canine Hip Dysplasia (CHD).  This has been quite a challenge when wading through the many websites that reference journals and studies that are over 20 years old.  However, I was able to find reliable sources with more current information in which I’ve listed at the end of this article.

CHD is a disease that most breeders think they have “nipped in the hips” so to speak.   Yes we have come a long way, but science has proved that even by mating non-affected sires and dams, we still run a 25% chance of the progeny being affected.  If you think about it, that’s a pretty high incidence rate with an average of one in four dogs being affected by CHD.

WHAT’S CHD?

CHD is where the head of the femur does not sit correctly into the hip joint socket, or acetabulum.  This creates loose movement and pressure which result in joint deterioration, bone changes, inflammation, and pain.

  • CHD is an inherited, polygenic trait. This means that several genes are involved in its clinical expression.
  • Development of CHD can be influenced by environment such as movement, age, & nutrition.  NOTE:  This is not to be confused that CHD can only be caused by environmental factors.  CHD has already been inherited, but environmental factors can affect the progression of the disease.
  • Affected dogs progress at different rates.  Some may barely show signs of pain or lameness, while others can hardly move.

The Orthopedic Foundation for Animals (OFFA) has a page that takes an in-depth look at the various grades and changes that occur in CHD affected dogs. [click here]

TREATMENT

Maintaining affected dogs at a proper weight and not allowing them to overeat has shown to be beneficial.  Mild forms of exercise such as walking, swimming, and light jogging are encouraged.  As with humans affected by Osteoarthritis, the more movement increases synovial fluid which acts as a natural cushion between joints.  Affected dogs should not be allowed to run and jump excessively.  Analgesic and anti-inflammatory drugs can relieve pain, but do not change the affects of the disease.  Carbohydrate polysulfates relieve pain and have actually shown to aid in normal remodeling of bones.

BREEDING

Breed only “Normal” animals with ratings of Excellent, Good, and Fair.  OFFA recommends breeding animals rated normal with strong backgrounds and whose siblings are over 75% normal.  However, OFFA also states that a dog with excellent hips, but with a weak family background and less than 75% of its brothers and sisters being normal is a poor breeding prospect.  By utilizing OFFA’s database and pulling up a “vertical pedigree”, you can more easily view the grades of ancestors.  I have found this a very useful tool during my research.  The trick is not to stop at the first four generations.  You need to go back further and take notes.  As you know, you most likely will be doubling up on a few dogs with any breeding.  (Visit OFFA.org > search for the dog’s name > on the dog’s page, click “vertical pedigree”)

Consider getting a preliminary hip evaluation on puppies before placing them.  This is recommended if you are unsure about the sire or dam’s backgrounds.  OFFA mentions that preliminary hip radiographs have shown reliability rates of 89.6% accuracy at 3-6 months, 93.8% at 7-12 months, and 95.2% at 13-18 months.  In the study referenced by OFFA, reliability of a prelim evaluation of normal hip joint phenotype decreased significantly as the preliminary evaluation changed from excellent (100%) to good (97.9%) to fair (76.9%).  A conclusion is that although the preliminary evaluations have proven reliable, it is recommended that a dog with a preliminary hip evaluation of fair should be reevaluated at 2 years of age (+plus).


Sources:

Genetics of Canine Hip Dysplasia, Cornell University College of Veterinary Medicine, http://www.vet.cornell.edu/research/dnabank/hipdysplasia.cfm

Canine Hip Dysplasia, Cornell University College of Veterinary Medicine Baker Institute for Animal Health, http://bakerinstitute.vet.cornell.edu/animalhealth/page.php?id=1104

The Dysplastic Hip, Orthopedic Foundation for Animals, http://www.offa.org/hd_info.html

Breeder Guidelines, Orthopedic Foundation for Animals, http://www.offa.org/hd_guidelines.html

Hip Prelims, Orthopedic Foundation for Animals, http://www.offa.org/hd_prelims.html

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