He may have foundered before the trimming and that made it worse. I seen a lot of founder but none caused by trimming. It can be made more painful by poor trimming though. You really should pull him or her out of the field and only feed hay, find a g...

Well im sorry to inform you but, When you enter a ring you are being judged on CONTROL of the horse and how well it is trained. So there for if a horse is loping , trotting etc. slow ,controlled and with its head down. That is a well trained animal. ...