There isn't a certain age for arthritis. If a dog has a joint injury early in life, they can develop it at any time. If a dog is over 5, they are more likely to feel twinges. Glucosomine is a standard ingredient in senior dog foods and really helps.

My daughter's Lab was 12 and couldn't walk very well for several months. I put her on Nutro Senior and a senior vitamin from Drs Foster and Smith. Within 2 months she was begging to go for walks and had no problem getting around.

Mary