I have to disagree with everyone else. You should switch him off of the puppy food right away. Most large breeds should not be kept on puppy food, and GSDs are extremely sensitive to bone/joint problems. Alot of these problems are from growing too fast, which is what puppy food causes a dog to do. There are too many nutrients in dog food that cause a dog to grow too fast, but you want your pup to grow as slowly as posible so that it is done correctly.