I have a black lab female who will be 10 in April. Up until 3 years ago I fed her Iams lamb meal and rice which she had been fed since birth. She started getting stiff in the joints during hunting season and was really beginning to show her age. Tried the aspirin route and it worked but not a good long term solution. Did some research and found that Purina Pro Plan Senior formula had the highest glucosamine/chondroitin content on the market. Put her on that and it was like somebody thru a switch. She was like a pup all over again, made a huge difference. Keep their weight down, and feed them a quality diet, not the cheap stuff. The amount of go she's got at her age is amazing. I'm thinking of trying a half cup a day myself!!