In basic terms hip dysplasia is the improper growth of the hip joint. This can lead to the hip moving and this in turn, over time, can result in arthritis also called degenerative joint disease, arthrosis, osteoarthrosis. It can be a very painful condition. Although it is more normal for large breeds to be susceptible to CDD, medium and even small breeds can develop the condition; the Orthopedic Foundation for Animals is an organisation that keeps a database of many canine conditions including CHD the Pug (a toy breed) is ranked the second worst with 63.8% of those tested (390 tests) being dysplastic and yet at the other end of the height spectrum the Borzoi ranked #157 with only 1.8% having a dysplastic result.
Damage caused to the cartilage that lines the hip joint, which results in CHD, may be onset by the result of trauma or it can be caused by inherited defects; an abnormally developed hip joint. When the cartilage is afflicted various enzymes cause a process which results in the cartilage loosing its thickness and elasticity. This thickness and elasticity has the important job of absorbing the loads placed on the joint during movement e.g. rising, running, walking etc. The degeneration is progressive and the enzymes and other debris spill into the joint lubrication fluid. This results in the joint be inadequately lubricated and the cartilage not receiving the nutrients it requires. As the cartilage gets thinner it eventually allows the synovial fluid to make contact with nerve endings which causes pain. In some cases to counter-act this the dog’s body produces new bone around the edges of the joint (spurs) and this added bone can cause the range of motion in the joint to be decreased and additional pain.
Dogs afflicted with CHD may exhibit many symptoms, lameness, unwillingness to walk upstairs, difficulty rising from a sit or a dropped (sleeping) position. They may also exhibit personality changes due to pain. The only certain diagnosis is by X-ray. Some vets may be able to see, from the X-rays, that the animal is suffering from the condition but normally it is advisable to have the X-ray reviewed by a professional using a recognised scoring system.
It is not possible to predict when clinical signs will develop; environmental factors such as the amount of exercise and the weather etc can make its mark on the severity of the symptoms observed. There also is no correlation between the severity of changes found by X-ray and the clinical findings for example dogs with severe arthritis can jump, play and run as if there was nothing evident and yet some dogs have barely any arthritic X-ray changes yet they are severely lame and clearly in pain.
Unfortunately some Basenjis have been known to suffer form CHD although the results are normally not ‘severe’ but borderline or moderate. Thankfully (based on statistical data available from the Orthopedic Foundation for Animals (OFA) which is based in USA) Basenjis evaluated in America under the OFA system are one of the least affected breeds at 3.2% of those tested being dysplastic and 23.7% having an ‘excellent’ score. It is a condition for which conscientious breeders test breeding stock and do not breed from animals whose score is high. During puppyhood good nutrition, not over feeding or over exercising has been known to reduce the rate at which CHD occurs.
In severe cases the only treatment for the joint itself is by surgery. There are numerous drug treatments; rather like arthritis in humans glucosamine and condroiton and other natural remedies have proven to be effective in relieving the pain of the condition.
X-Rays for PennHip and AVA systems
There is a much debate about which hip scoring system (PennHIP Vs OFA) is the best method for reducing canine hip dysplasia. I have been hip testing since 1998 using the OFA/AVA system. In that time the results of my dogs have been ‘good- excellent’. Tambuzi has an average score of about 4. However, the mean has not really improved. That is to say breeding excellent to excellent has not necessarily increased the number of excellent results. There has been no profound improvement in the median. There are many factors which play a role in HD. However, it should be expected that litters being reared in a fairly consistent manner with parents with similar scores that results would improve. The New Zealand Kennel Club has more evidence that AVA based systems turn in circles rather than making expected improvements. The future of the NZ scoring system looks to be switching from an AVA based scoring to the PennHIP method as from the beginning of 2014.
Tambuzi Health Management Program – cHD
Even though there is a fairly small percentage of Basenjis have been scored as having CHD. I have adopted the following into the Tambuzi Health Management Program. I believe that due to a number of factors, the occurrence is probably higher than reported. I am currently transitioning to the PennHIP method of hip evaluation. This method is predictive and has been accredited as being far more accurate than the OFA/BVA/AVA systems.
- Mandatory: Breeding stock must be examined and scored using the AVA or PennHIP systems before breeding.
- Acceptable Scores – AVA: Dogs with a score (left +right combined )lower than 10 may be used for breeding.
- Acceptable Combinations – AVA: Two dogs with a combined score of 12 and less maybe used. However, no one dog’s score can be higher than 9. Where possible an individual with a score greater than 8 must be mated to an individual with a score less than 5.
- Acceptable Scores – PennHIP: Dogs that are in the tightest 40% of the breed; the 60th percentile or better will be used for breeding.