HI there I am ShreyaYou got a thing to concern. I'm also having Great Dane since 16 months I shall detail you the food schedule that I had followed to my dog. Firstly I make sure that it is better to give Royal Canin as food. Since your 7 months puppy, you should use Royal Canin giant puppy food. it should be thrice a day and better don't give milk to puppy, chapatis and egg were ok you can provide. This would be ideal for this age.