Started our 20 year old gelding on Previcox about two weeks ago after suspected arthritis in hocks (we are waiting for X-rays). Today, he would NOT be caught in the pasture! Running around like a colt, kicking his heels, etc. He is definitely feeling better - my daughter can feel it under saddle too (he's her horse) and I don't see any stiffness in the back end anymore. We're happy with the Previcox for now, though once we have a confirmed diagnosis, we'll look at other options. We did not want to bute him because he has a tendency to get ulcers. The Previcox is a daily (tiny) pill in his food. Easy to administer.
The equine version is Equioox (sp?) but is more expensive. Our vet just sold me Previcox which is actually for dogs.