A few years ago we adopted a 6 year old australian shepherd. Wonderful dog. A few months ago we were playing ball, he was winning, and he came back limping. On our next vet visit I mentioned it to him and he checked (feeling between Rileys back legs) and said it was something that happened to dogs when they play ball and that there was an operation we could have done that would correct the problem. I spoke to one breeder who told me that none of his dogs lived past 10, still can't figure out why. I looked it up on the web and various sites say anywhere from 12-15 years. We decided to try glucosamine instead, our other dogs are on it, and now Riley has very little limping unless he is out jumping or climbing, it's been about 6 months. We try to keep an eye on him and not let him do those things.