English Shepherd

The English Shepherd

An American Breed

Canine Hip Dysplasia

Hip dysplasia ("bad development") appears in people and many species of animals. In some breeds of dogs, it is the most common cause of osteoarthritis or degenerative joint disease.

Research on canine hip dysplasia (CHD) suggests that CHD is a complex disease. There are no simple answers or solutions to this problem. However, many aspects of the disease have been repeatedly and independently documented and are generally accepted by the scientific community. Three important ones are:

CHD is caused by the presence of many genes. While no environmental cause has been found, many environmental factors contribute to its expression in any particular dog.

The only current means for reducing the occurrence of CHD is by selectively breeding for normal hips.

Radiography is the accepted means for evaluating hip status.

Most inherited traits in animals involve many genes. Only some puppies will have the same combination of genes for a trait as their parents. Some will have a more desirable combination while others will have a less desirable one. As the number of involved genes increases, the possible outcomes also increase. In addition, remember that it is also possible for different genes to have a different level of influence on the trait, complicating the outcomes considerably. Predictions of a specific outcome from a particular mating involving traits that involve many genes is currently impossible.

A dog with excellent hips but with more than 25% of its brothers and sisters affected with CHD is a poorer breeding prospect than a dog with fair hips and with less than 25% of its brothers and sisters exhibiting CHD.

Multiple genes are involved in the inheritance of CHD, and many other factors influence its development, including body type, size, growth rate, and nutrition. Overfeeding and dietary supplementation for maximal growth have been shown to increase the incidence of CHD in young, growing, large breed dogs. Conversely the development of CHD can be delayed, and its severity diminished when the growth rate of pups is restricted.

Environmental factors such as type of food and exercise during puppyhood have been shown to affect the symptoms displayed by puppies in the same litter. However, subsequent generations from both the puppies who showed symptoms and the puppies who did not show symptoms ended up with the same rates of CHD, meaning that while the individual dog may be affected by factors such as the type of food and exercise, the genetic material contained in that dog, reflecting its entire history, is what determines whether a dog has the potential for being affected with CHD.

It's best to keep puppies from any kind of repetitive jumping for the first year or so in life. It's also best to avoid sustained exercise until a puppy is at least a year old. Sustained exercise includes: jogging with owner, weight pulling, mushing, running with owner on bike, etc. Even for dogs not at risk for CHD, it's wise not to exercise too strenuously too early, as such exercise may interfere with proper growth of joints, leading to other problems such as arthritis or Osteochrondrosis Dissecans (OCD), a disorder of the immature long bones.

CHD can not be diagnosed by observing how the dog moves, acts, lies down, etc., even though owners may use the dog's behavior in these areas as an incentive to visit a qualified vet for a proper examination The clinical signs may be caused by other problems; therefore, a complete orthopedic and radiographic examination is required before arriving at the conclusion that the signs are caused by CHD.

There is no known method of preventing CHD except for a thoughtful and carefully executed breeding program with regular radiographic analysis of all stock before breeding. A breeder who encourages puppy buyers to x-ray their pups when the time is right will be able to acquire a good deal of useful information for their breeding program without incurring additional cost.