
OUr Lab, now 12, was part of a feeding research program (done on Labs, Rottis and German Sh. I think) that advocated NO PUPPY FOOD. The idea being that extra supplements in much commercial puppy food causes their bones to grow faster than their ligaments and tendons leading to possible stress injuries and joint problems later in life. We have adhered to the program and she is still on the same food as all her life, Eukanuba Adult Maintenance. She has a wee bit of arthritis in her right shoulder. We also give her a 900 mg. capsule of Glucosamine with Chondroitin twice a day, with meals. She will sometimes be a bit gimpy after 12 km of cross country skiing or hiking up and down lots of hills and then might get half of a 325g mg aspirin. She is always fine the next morning.
Consistency in her exercise is also key as she is no longer able to be a "weekend warrior." I have found, perhaps strangely, that MORE exercise works best to prevent lameness. She cannot do the 12 km on the weekend if all she gets mid-week is short walks. I have had to introduce a longer outing at least once mid-week.
This works for us. I agree, I don't know if the food matters that much as long as it is a good quality food.