Going back in history, it was pre-1930's to find a time when the subject of "hip dysplasia" was not mentioned in any form. Those were the times when people went to the butcher shop and the corner market and got some meat scraps and fed what was left at the dinner table from the three meals a day that the matriarch of the family collected at the end of each meal.
The depression and ensuing years brought about the change of the industry and the change of the products that came out of the family pet world. There evolved an industry that processed high carbohydrate grains, like corn, into pet foods that produced an unintended consequence of making cheaper, more easily accessible, pet foods but of much lower quality.
The unfortunate by product of using high carbohydrate corn(2,200 carbohydrate calories per pound) and building a non-meat ration resulted in a weakening of the femur and the acetablumen(the three bones that intricately fit together to form the cup for the end of the femur to fit into). This brought about the emergence of CHP(canine hip dysplasia) Now, when the malady arose, a lot of veterinarian and researchers tried to show that this was a genetic consequence.
From the 1930's until the 1960's, the breed associations in the United States and Europe tried their best to use genetic selection to aleviate the problem, to no avail. They found CHD problems in 70 to 75% of large breed dogs and after those three decades of work, they felt all the work had reduced the incidence by almost 5%. Not much to hang your hat on.
It was in the sixties that two men, one a veterinarian and one a scientific journalist began to explore nutrition as a major cause of CHD.
It was amazing the controversy that resulted from their findings which many years ago led to law suits and even some criminal complaints but the facts are the facts. These two researchers found that the use of high carbohydrate grains, especially corn, resulted in muscle and skeletal weaknesses that were the result of softening of the tissue and the weakening of the joints and now with some larger breeds, three-fourths of all those dogs have joint and walking problems.
NOTE: We are going to invest the time of several articles and a lot of research to further look into this problem and try to explore the economics of what this malady costs in actual dollars.