Thanks, TWH Girl, for the info. Found the “Bute test” very interesting. I hesitate to try it though because my horse has had ulcers in the past. He is on Previcox daily and had the loading dose of Adequan injections last Feb. and on maintenance now. He recently had his back fetlocks and hocks injected because they flexed positive…but this refusal to pick the right lead canter started after all of that!! He is a very willing and stoic horse so I know it has to be a pain issue rather than behavior…he will not even pick it up on a lunge line. Headed back to the vet on Monday. Thank you for the time you took to respond and your concern. Good luck with your guy! Hope the treatment plan works for him!!