What is the most likely cause for the inflammation of a horse's bursa and deep flexor tendon areas with no signs of lameness?

The most likely cause for the inflammation of a horse's bursa and deep flexor tendon areas, particularly when there are no signs of lameness, is windpuffs. Windpuffs, also known as hygromas or soft windgalls, are swelling that occurs around the horse's joints and tendons, typically resulting from the accumulation of synovial fluid. This condition is often seen in areas where there are bursa or tendon sheaths, particularly around the superficial digital flexor tendon and the deep digital flexor tendon.

Windpuffs can arise from various factors such as excessive exercise, increased workload, or even aging without necessarily causing pain or lameness in the horse. Since they are considered a benign condition, horses with windpuffs might still perform well without showing any signs of discomfort or issues with mobility.

In contrast, conditions like carpitis, capped elbow, or dorsal metacarpal disease could potentially indicate more serious underlying issues, such as bone or joint problems, which typically present with signs of lameness or discomfort. Therefore, the inflammation associated with windpuffs aligns with the scenario described, as it occurs without the associated signs of lameness seen in other conditions.