Awww!!! He's getting HUGE. Reminds me a lot of my old great dane (sizewise). How's he like jeep rides?
Likely you already know this but his food and water bowls are up off the ground and no playing/running for at least 30 min after he eats/drinks? Just below chin level for him? If you're not familer with this (or anyone else who has big dogs), raising the food/water bowl's help prevent Bloat. With large breed dogs, they like to gulp their food down. If the dish is low, the animal is prone to gulp large amounts of air, also. Most large breed dogs have deep chests, so there's lots of room for the stomach and various organs to move around in the abdominal cavity. If the dog gets very active (playing/running/jumping) directly after eating/drinking the stomach can swing upside down (think those twisty balloon's people make creatures out of). It's extremely agonizing for them and will kill them without a $1-3k emergency surgery that can't guar. they'll still live afterwards.