You notice that your competition horse is starting to shorten his stride occasionally. He is stiff and takes longer to warm up. Perhaps he’s showing other signs of physical discomfort. Your veterinarian examines him, and the result is what you expected–he is developing arthritis. Now what? Should you start him on a joint supplement of some type? You know that every time you open a horse supply catalogue, there are pages of advertisements devoted to oral joint supplements. What are all those ingredients, how do they work, and (most importantly) do they work at all? That last question is the big one, and the jury is still out.

What Is Cartilage?

Cartilage is a resilient tissue covering and cushioning the joint surfaces of bones. The cartilage matrix is made up of collagen fibers, glycosaminoglycans (GAGs, natural joint lubricants), and sodium hyaluronate. Both cartilage and joint fluid act as shock absorbers and buffers to keep bones from rubbing together (see the illustration on page 86).

Cartilage doesn’t have its own blood supply; it must rely on surrounding tissue for its nutrients. When cartilage can no longer maintain proper metabolic activity, the destructive processes begin. This happens with normal aging and physical wear and tear, and the end result is that the joints become less flexible