I didn't see your post so I don't know the horses issue, but just be careful what you introduce. The other thing is to talk to a vet. Won't cost you a thing and it will save you in time and money to get the right product. Good luck. Posted via Mobile Device
We need to know the problem before any appropriate advice can be given. If the issue is arthritis, you can feed calcium (in the form of either lucerne/alfalfa, or a supplement), and feed MSM and glucosamine in conjunction with each other, to help promote healthy joints and keep him more mobile.
If not arthritis - then we need to know what it is!