Also as your training progresses, your horse will learn to breath
correctly--something you can't teach directly but can influence by
controlling your own breathing. Take a very deep breath, hold, then
exhale as slowly as possible while you are trotting at a slow to moderate
pace. And don't be too concerned about "hard conditioning" right
now--remember long, slow, steady does the job better!
When you dismount, stand by your horse and breath slowly, drop your
shoulders and relax your posture, do a soft focus on the whole
horse--don't just "stare" at the flank--and present a calm, relaxing
image. Your horse is anticipating "more" and his rapid breathing could
simply reflect a "ready posture".
Give him time. It took our Freddy 2+ years to get the breathing down pat.
Diane @ Safe Haven
Allentown, PA