Treating arthritis in horses is best dealt with in a multi-modality approach: exercise, anti-inflammatories, joint supplements and injectible joint therapies. You can choose the modalities needed to get your horse relief for his specific problem.
As much daily turnout as possible is the first place to start. This is very important for arthritic horses because standing still leads to stiffness. Motion helps keep joints moving freely.
Bute used as needed for pain can be done safely. The risk of adverse reactions is based upon the dose given, so giving the minimum amount necessary to control inflammation will provide relief for your horse without un-necessary risk. Just like you taking aspirin or ibuprofen for pain, you don't just take it--you take only what you need. Bute provides anti-inflammatory action for 24 hours after a single dose, so you don't necessarily have to give it every 12 hours. And studies showed that there was no more benefit from giving more than 2 grams of bute per day, so there is no need to give high doses to get relief. You may need to give no more than 1 gram of Bute every other day or even only when you know your horse is going to be worked and may need extra pain relief. And anti-inflammatories don't just "mask pain" they actually treat pain and can help prevent further arthritic changes in the joints which are caused by the body responding to pain and laying down more bone.
Oral glucosamine and chondroitin supplements have been proven effective in a study performed by the AAEP. However, the amount of glucosamine necessary to show benefit is generally higher than that in most over-the-counter supplements. 10g of glucosamine per day is considered the therapeutic dose for the average adult horse.
Injectible products like Adequan IM can give great results in arthritic horses and after the initial month of loading doses often costs no more than a month's supply of oral joint supplements. So for the cost, it can give bigger bang for your buck and is something you might want to consider. And if the pain is significant you could even go to joint injections to treat inflammation and provide lubrication directly to the joint that is the problem. But the cost is often prohibitive for a pasture puff.
Licensed Veterinary Technician