My mare was diagnosed with spinal arthritis too. Shes on everything she possibly could be for joints and that has her maybe 75% back to comfort. I am hoping to work with our local Bowen therapist to help keep everything around her spine in shape too. I don’t think equine Bowen therapists are common but massage or acupuncture would be good too. I would be wary of chiropractic work, though. I wouldn’t want my arthritic spine cracked!