Hip dysplasia is one of those conditions that all dog breeders are very well aware. Responsible breeders make considerable efforts to eliminate it from their dogs for decades. Almost every breed’s parent club recommends screening breeding stock for hip dysplasia (HD). Orthopedic Foundation For Animals (OFA) in the USA was founded for this very reason.
Enormous effort has gone into monitoring the inheritance of the disease. There is an incredible accumulation of data spanning over 50 years. Yet, the consensus is now emerging that while the causes of hip dysplasia do have a genetic component, there is a larger environmental component to consider.
One can mate two parents with excellent hips and get dysplastic offspring. Similarly, two dysplastic parents have been mated resulting in pups with normal hips.
Hip dysplasia is a concentration of factors. Where there are certain genetic weaknesses such as soft tissues, such as ligaments, there are environmental stresses that are placed on these developing joints. This causes a pattern of progressive remodelling or reshaping of the joints and leads to degenerative joint disease.
It is important to note that HD affects breeds with a higher ratio of weight to height. Research indicates that overweight individuals within the same breed to be twice as likely to develop the condition.
OFA data lists Bulldog and Pug as the two most affected breeds as of 2016. The Italian Greyhound and Whippet as least affected. Talk about compact weight juxtaposed to light, lean body!
A study compared Lab puppies on a restricted diet to those on a control diet. The results were striking (Vanden Berg-Foels et al 2006).
At 6 years old, puppies fed a restricted diet had less evidence of HD than the controls. The heaviest dogs were affected the most.
Everyone thinks chubby puppies are too cute. However, their risk of developing orthopaedic problems is much bigger (pun intended) when compared to lean puppies.
Before measuring perfectly controlled portions of food for your puppy, you can do something else. Reduce their environmental risk for hip dysplasia.
The Whelping Box and HD?
There might be another environmental factor we are overlooking.
The whelping box.
Take a look at some videos of wild canines. You will notice how the den is shaped like a bowl. The surface is compact dirt.
When the pups are nursing they have great traction under their feet. They do not use knees and bellies to crawl. Pups in a flat whelping box are mostly forced to do this.
The concave shape tells blind and deaf newborns where “up” and “down” is. They all pile at the bottom of the den, forming a naturally warm gathering.
The remarkable differences between a natural den and a man-made whelping box may assist in explaining why all puppies are born with normal hips and develop dysplasia afterwards. It may also help explain why wild canines do not suffer from hip dysplasia.
This is the big question: Does the damage happen sometime after birth in a man-made environment?
Multiple studies show puppies to have normal puppy hips at birth. They also show that many puppies have signs of laxity in the hip joint by the age of 2 weeks. This is where the head of the femur does not fit tightly into the acetabulum.
Joint laxity is a key risk factor for developing hip dysplasia.
So what happens in those 2 weeks?
When looking at newborn puppies nursing in a whelping box, you will see:
- feet flaring about looking for traction, or
- puppies putting their weight on knees and hips.
Over-flexing the legs and putting weight directly on knees and hips put undue stress on the hip joint. This can result in luxating that joint or causing it to move out of its normal position.
Can some easy adjustments to a whelping box make a difference?
Here is a simple experiment was performed by Magda Chiarella, breeder of Norwich Terriers for 20 years.
The first photo shows my litter nursing in a flat whelping box lined with a Sherpa blanket. The next photo was taken after I put a rug pad under the blanket. The pad changed the traction on the bottom of the whelping box.
Notice how the weight distribution changed from knees and hips to feet.
She went a step further in creating traction by placing a rug pad over the blankets. All of a sudden the puppies no longer looked like cute blobs. They started lifting weight up on all their limbs.
She videotaped the result in how the puppies moved. Watch this short video:
Is she on to something?
She also created a concave den. In the whelping box, she padded the outer rim with towels. Once the shape curved inwards from all directions she laid a rug pad and then a Sherpa blanket over it.
I am inclined to agree that a den curved inwards, with a surface that has good traction may be a good idea when trying to protect puppy joints. Does anyone have any further experience with concaved dens shaped in their whelping boxes? Let us know.
Excerpts are taken from Magda Chiarella, breeder of Norwich Terriers for 20 years