If you don’t want to give it to him, but you don’t want grief, just lie to your trainer. If you are doing any part of your own care at the show it’s super easy to say that he had his paste in his morning feed.[/QUOTE]
Don’t lie to your trainer. You hold the money and the power. Stand up for your horse and for clean sport.
And FWIW, your horse doesn’t sound too bad. I have made up hunters and right now I have a hot baby dressage horse. So much of getting green horses to be calm is being skilled about teaching them to do their job… so that they understand it and can be calm for reasons of self-confidence.
Just take your horse to the little show and focus on giving him a good experience. Get as far into your day of competing in the ring as his mind will let you. If he needs to play on the lunge early to blow off some steam without getting in trouble, that’s ok. But it’s even smarter to offer him a handwalk around the place first. Sometimes horses just need time to look and think. If you can get him to “make his peace” with the busy show grounds this way, you saved his legs and also taught him how to chill.
When you saddle him and ride him, go slowly, insisting that he does all the normal stuff like stand still, focus enough on you that he’s not screaming for a buddy, keeps his head at a normal level, doesn’t paw tied to the trailer. Let him know that the same rules apply at the show as apply at home.
If you can teach a horse that you’ll give him the same job and treatment no matter what, no matter where he is or what’s going on, he’ll learn to find safety in just listening to his rider.
If this were my horse, I’d let his rideability decide whether or not I actually showed him. And it would also tell me whether or not I’d try to be competitive or slow, relaxed and careful while I was on course.
If you do this enough-- and with an eye to what’s going on in your horse’s mind-- you can teach them how to go to a horse show. They don’t come out of the box knowing that!
Maybe this is all obvious to you and your pro. I hope so. I write all of it because it might not be. Maybe some people aren’t good at teaching young horses, and that’s why they look for chemical solutions. Your horse definitely sounds trainable, OP.
And how do you know if you were right, trainer was wrong and he didn’t need a calming paste? He ends the day calmer than when he started it.