My friend said her horse got really nervous and spooked at everything when she gave him calm and cool, now this was years ago, but she said she has had other people complain.
I work my horse every single day and we ride for hours sometimes and he could still go... I could ride him all day long and he would still want to keep going. He never calms down. I talk to my vet about everything that goes on with my horse and guitar you might want to do the same thing, you know just see what their opinion is on what is going on or if they have a suggestion. My vet suggest quietex for my horse.. He has been seeing my horse for 6 years now and is up to date on every supplement and feed my horse gets. He is a saddlebred and he just needs to chill. Personally i think some horses just need a little something sometimes. My friends walking horse was a maniac and she put him on quessence don't think that is spelled right, and he chilled out and she slowly weaned him off it, and he works AMAZING for her now. I don't give my guy his year round, because we can't show with most supplements. I want him worked up when i show him, but he is completely mellow at shows.
Like how high strung, and why does the trainer want her on a supplement?