You should legitimately be asking yourself, why a veterinarian is placing so much emphasis on saddle fit and saddle fit problems? After spending many years specializing in equine performance issues, I, unfortunately found that saddle fit is often the root of problems that can lead to not only performance and behavioral deficits, but also back pain and even unsoundness.
My obsession with saddle fitting is that saddles affect muscles. I refer to muscles as the forgotten system in veterinary medicine. Veterinarians involved in performance problems and lameness tend to think in terms of tendons, ligaments and joints. After all, those are what show up as injuries and require treatment. However, the tendons and ligaments respond according to the amount of tension or lack of tension, as well as the stresses put into and onto joints according to one anatomical structure - the muscles - those in action or those failing to be appropriately in action.
We all recognize that a very badly fitting saddle can be a torture device for the poor horse. But what many do not recognize is that, what seem to be relatively minor saddle issues gradually affect muscles and their ability to function properly. An insult to one muscle works progressively to spread that insult to another and yet another muscle in a chain reaction. That chain reaction will affect way of going, performance and foot conformation. Carried to its logical conclusion, it will clause firstly, performance deficits and progress subsequently to sub-clinical lameness. Eventually, the problem will lead to outright lameness.
At this point, this line of thought might seem exaggerated, but articles will be posted to this website to explain this phenomenon. Lameness that can be attributed to having started with saddle fit include suspensory issues, tendon strains and bows, carpal fractures, degenerative disease of knees (carpal joints), hocks and stifles.