I don't use puppy food. I never did believe in it in the first place, but especially don't now after what happened to Ripley. He was weaned onto a quality puppy food (Now! Puppy) and when we got him from his breeder, we continued with it. She always recommends switching to adult or ALS food by the time they're 4 months old and so that was what we were going to do. But then he started growing too fast and knuckled over (so basically he woke up one morning with deformed looking legs and I panicked a little). We took him to the vet (one that actually is knowledgeable about nutrition) and we were told to stop feeding puppy food and to give him Vit C to help correct it. He said that his problem is common in larger breeds fed puppy formulas apparently. And I don't believe puppy food is necessarily bad (it's likely better for some puppies), but I won't ever feed it again. Especially to a dog that is going to grow to be more than 50lbs. My puppies have all done well on adult or ALS foods.