As team roping has evolved and the price of a decent horse has escalated, more people are having a horse they are interested in buying evaluated by a veterinarian for state of soundness before writing the check. I believe there has evolved a greater ability to evaluate the status of the horse by way of greater knowledge, experience and advanced technology from the veterinary profession. However, there are still situations where the decision to buy or not buy a horse based on a soundness evaluation can be in question.
The major factor of a soundness evaluation is a thorough physical examination of the horse. Abnormal findings physically or conformationally are noted, and then one proceeds to moving the horse at the trot on a hard, level surface in all directions. Tests such as applying hoof testers and flexion of the leg joints are evaluated. With higher prices for horses, radiographs of important structures are often done either because of a request by the prospective buyer or questionable findings on the physical exam. When all is said and done, it seems horses fall into one of four categories.
The first category is the horse with no evident problems physically and no apparent changes radiographically. The second category is the horse that seems fine physically, but has some subtle changes radiographically (on X-ray imaging). Interpreting the significance of these changes can be challenging. Many subtle changes radiographically are considered non-threatening, or in a way normal, for an experienced horse that has been working hard in his lifetime.
The third category is, in my opinion, the most difficult to make a decision on. It's the horse that is moving soundly and has been performing the job, but has more serious radiographic changes. This horse may also have some abnormal response to hoof testers or flexion tests. The fourth category is the horse that is not moving soundly and has radiographs with changes that explain why.
As I mentioned, horses that fall into the third category present a dilemma to everyone concerned. The decision on whether to buy the horse or not often comes down to other factors. Factors such as how well the horse "fits" the prospective buyer, knowledge of the horse's recent performance history or the price relative to the horse's ability. In other words, it's a calculated risk.