Why does my horse fade off the fence during the drive?

A horse that fades off the fence during the drive — drifting away from the arena wall during the fence run so that the cow has room to escape between the horse and the fence — is creating the gap that removes the fence as an effective boundary and turns fence work into open-arena cattle work where the horse's positional advantage disappears. Fading off the fence during the drive reflects a combination of positional discipline problems, cattle-reading issues, and sometimes the horse's instinct to give itself space from a cow that it is approaching closely at speed. The most direct cause is that the horse is not maintaining its line parallel to the fence as it drives the cow — instead of running a path that keeps consistent pressure on the cow from the side away from the fence, the horse curves outward so that the angle between its path and the fence increases rather than staying consistent. This can reflect the horse's tendency to follow the cow's drift if the cow begins to angle away from the fence, which means the horse is tracking the cow rather than maintaining the driving position that keeps the cow on the fence. The correction involves developing the horse's understanding that during the drive phase its job is to maintain a parallel path to the fence regardless of what the cow does laterally — the horse should be driving forward along the fence, not tracking the cow's every lateral movement. Specific exercises that develop this parallel drive include working with cattle that tend to drift off the fence, asking the horse to maintain its fence-parallel path and use its position to push the cow back to the fence rather than following it into the arena, and developing the horse's willingness to hold its line under the pressure of cattle movement that instinctively draws the horse off course.