The pyloric ulcers were healing, and it sounds like the misoprostol and sulcralfate combination was successful. However, you have indicated that the squamous ulcers are still a problem with healing and staying healed. It is noteworthy that the omeprazole injection site gets very swollen. Isn’t UlcerGard omeprazole in a paste form? That to me says a reaction to the medication, but I am not a vet or pharmacist. What happened with the allergy testing?
If the horse doesn’t appear to have pain anywhere else, and the horse is used to and comfortable with his herd arrangement, it seems like he is ingesting something that is really upsetting his system, or he may need more turnout than he is used to to keep him moving as he has been worked or is working at a pretty high level. Could he have some arthritic changes?
