Did your vet make the ulcer assessment or the trainer?
If the vet made the assessment, what did he/she suggest for treatment?
My 27 yr old Arab has flare-ups of gastric stomach ulcers every winter. He is the one of my four horses that needs all that lush green grass to keep his tummy quiet. By the end of winter, even feeding him bagged forage that I soak, his ulcers flare up. They have been since 2004.
I buy 30 days of Omeprazole from the vet for a little over $100 (can't remember exactly).
He's always better in a few weeks but I use the 30 days up anyway and he's good for another 9 - 10 months BUT he doesn't get worked either. He is fully retired unless somebody's toddler wants a happy horse memory
He also does not eat any grain. I feed him Triple Crown Senior, rice bran, soaked alfalfa pellets, Omega-3 Horseshine and a pre/probiotic.
That all being said, if your horse has hind gut ulcers, I have one of those too
He is on Succeed, a Prebiotic that costs $90/month. He hasn't had an ulcer flareup or colicked since last October. He is 25+ years.
Feeding these types of horses 3 - 4 small meals (their feed pan stuff) with free choice hay and/or pasture also helps a lot
Hope this is some help to you