Common Health Problems

HIP DYSPLASIA

 

Hip dysplasia in simple terms means an abnormal formation of the hip joint where the head of the femur does not fit snugly into the pelvic socket.

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The disease is the result of a combination of factors, from a variety of genetic weaknesses and environmental stresses that fall into a programmed pattern of progressive remodeling and degeneration of the hip joint and finally resulting in degenerative hip joint disease.

 

The genetic cause of hip dysplasia is unknown. It is widely accepted that the disease is not controlled by a single pair of genes of which one may be dominant, but by a series of genes acting in combination. It is polygenetic (involves many different genes) and multi-factorial (influenced by many non-genetic factors).

 

Genetic and environmental factors that can trigger events that bring about the condition are:

 

Genetic inheritance

To date,  the many hip dysplasia screening schemes have not reduced the incidence of hip dysplasia significantly.

 

Body size

Larger breeds have a higher incidence of hip dysplasia.

 

Body type

Dogs with a heavy conformation have a higher incidence of hip dysplasia.

 

Growing pattern

Large breeds tend to grow much too quickly for their biology to keep up. They often show uneven growth, with the rear end growing over a few weeks, and then the front end tries to catch up. The mechanical leverage that the muscles would normally exert across straighter angles is therefore much reduced and decreases the ability of muscle to protect joints from injury.

 

Excessive weight gain

There is a direct correlation between overfeeding rapidly growing, large breed dogs and the frequency and severity of hip dysplasia. More and more researchers point out that overeating can significantly affect the outcome of a puppy’s hip conformation.

 

Excessive activity

Excessive physical activity such as romping up and down stairs, running and slipping on smooth tiles and jumping in and out of a van during the growing phase subjects the growing hip structures to unwarranted stress and trauma and should be avoided; especially during the first six months, as this is the most critical growth period. The effects of this excessive stress are worsened in an overweight pup.

 

Nutrition/Diet

There is a perception that calcium supplementation prevents HD; this is not true. On the contrary, evidence indicates that a too high calcium intake may actually cause skeletal developmental problems. Other than that, diet does not seem to be important except when it results in too rapid a growth rate or excessive weight gain.

 

With regards to nutrition, the real goal should be to keep growing puppies from becoming overweight. Dogs grow much slower when they are free to run and play all day and night because much of their food intake goes into play and running. A single puppy that lies around all day grows very large, very fast and its muscle tone is a small fraction of that of a puppy that plays all day long. It is therefore most important that a puppy’s is free to run and play, or if this is impossible, to restrict the diet of the growing puppy and to restrict activities which will exhaust his muscles and leave him unable to protect joints from injury. It makes sense to have a lean puppy that is exercised moderately (Guideline: 5 min walking for every month of age) on a regular basis.

 

Clinical signs

The disease is not diagnosable in very young puppies under the age of 24 weeks.

 

Clinical signs of hip dysplasia include a swaying hind leg gait (not to be confused with a puppy that is well or over angulated); hind leg lameness; muscle wastage around the hindquarters; reluctance to exercise; fatigue during exercise; inability to climb stairs or jump up. Hip dysplasia is diagnosed from the presenting history and physical examination but must be confirmed by taking radiographs of the hip joint. The position of the dog is critical when the X-ray is taken. Faulty positioning may either render the radiographs useless or make the hip on one side look better (depending on whether the dog is tilted left or right) or worse than what it really is.

 

Combating the disease

German Shepherd Dogs are by far not the worst affected of the large breed dogs. The Orthopaedic Foundation for Animals (OFA)          currently lists 40 breeds with worse X-ray diagnosed problems than German Shepherd Dogs.

 

In almost all cases where canine hip dysplasia is diagnosed, the breeder is blamed although much of the problem has come from thousands of years of less than natural selection resulting in the domestication of the dog. It must be understood that you can get it in your breeding program even if you breed from animals that do not have hip dysplasia. Studies have indicated that the mating of two dysplasia-free dogs can yield as much as a 25% incidence of the disease.

 

Hip Dysplasia is an extremely complex disorder; efforts by dog breeders and veterinarians to reduce the prevalence of the disorder have proven marginally effective. In the meantime, until (if ever) the genetic markers are identified, the most practical solution to combat the disease is to select against its presence in the parent breeding stock through a compulsory hip screening scheme; but with the understanding, that this in itself, does not guarantee anything else other than an increased chance that the pups will be dysplasia free.

 

It must be understood that in spite of the many schemes aimed at eradicating the disease worldwide, it is still prevalent amongst most of the larger breeds. The problem is as old as the existence of the domestic dog and will, in all probability, still be with us for many years to come.

 

CONFUSING “LOOSE HOCKS” WITH HIP DYSPLASIA.

 

"Loose hocks" are common in German Shepherd Dog puppies that have a lot (sometimes too much) of hind angulation. Like children, puppies go through awkward developmental stages and when a puppy first starts developing more angulation as he grows, it takes a while for the puppy to learn how to handle the new proportions. Also, the femur is disproportionately short for quite a while in puppies, thus contributing to the loose wobbly hocks. GSD puppies go through a number of awkward, disproportionate, and sometimes even downright ugly stages of development before they finally come together and become a balanced elegant adult.

 

Loose hocks are totally unrelated to hip dysplasia. In fact, a severely dysplastic puppy at age 4 to 6 months will stand with its knees together under the body and shift its weight forward onto the front to try to take weight off the rear. This stance is almost the exact opposite of a dog that is standing cow hocked with knees turned outward and hocks turned inward. The GSD single tracks, all four feet coming toward the centre to form a single line of tracks as it moves, and some people mistake normal single tracking for cowhockedness, etc. since the feet come inward to the centre as the dog gaits.

 

Hockiness normally straightens as the puppies gain muscle; particularly if they have a lot of rear angulation. Many dogs will stand hocky but when they move they move true and effortlessly. If the dog is truly hocky, depending on the severity of it, it can be a problem but only to the extent that it effects effortless movement and endurance.