Hi Siva, congratulations for the new member of your family. Now as far as growth of this puppy is concerned, What is his age? There are a lot of issues while taking care of giant breed dogs (esp during first one yr). First of all you need to curb your excitements regarding how big your dog is going to be. C'ause this all depends on the lineage of the dog. If his parents are from champion lineage, he will assume a simm structure (Though exceptions are always there). Feed him only premium dog feed (if you r feeding him commercial dog food). Royal canin is good and despite having excess protein contents gives good results. Take care that your dog is not exposed to heavy exercise during puppy stage. These dogs though look big but are still very young and their bony skeletal is not mature. I would also recommend you to visit "Great dane lady.com", a lot of useful information is available there.