What is one cause of saddle sores in horses?

One primary cause of saddle sores in horses is an unbalanced saddle, whether due to the saddle itself, the horse's conformation, or the rider's positioning. When a saddle is unbalanced, it can create uneven pressure points on the horse's back. This uneven distribution can lead to friction and rubbing, which in turn causes irritation and sores over time. An unbalanced saddle might shift during riding, exacerbating the issue and increasing the chance of developing sores.

Consideration of the other options provides valuable context. Excessive grooming does not typically contribute to the development of saddle sores; in fact, it can help keep the horse's coat healthy. The use of longer stirrups may impact the rider's position but does not directly relate to saddle sores. Riding with a loose saddle blanket can cause discomfort, but it would not be as significant a factor in the causing of sores as an unbalanced saddle. Understanding these connections is crucial for preventing saddle sores and maintaining a horse's comfort and health.