Isn’t this where someone should suggest using a pelham?
Take heart in knowing you are not alone in this struggle.
I too have a “hot” little Arabian and during trailering and shows this can be compounded, add in his general anxiety and it is a total melt down. The first time we trailered him alone I thought he was going to have a heart attack (litterally). Constant jigging, covered in sweat, shaking and heavy breathing. It was absolutely horrifying.
The most important change I made was taking him off sweet feed entirely. Now he gets a fat supplement and a ration balancer as his general anxiety means he can be a pacer in his turnout and seems to burn a ton of calories during the day.
I also found a stress relieving agent (I used Stress Ex) the day of the show or trailering helped a lot too.
I am also considering putting him on a daily stress reliever but am going back and forth on it. My trainer does not think it is necessary but I think I would like to try it.
Also a calm, confident rider helps too. Of course that is good advice but hard to follow if you are like me and are less then perfect and confident at times.