Welcome and congrats on new baby! You've come to the right place.
First, you want to crate train him. Make sure you have a blanket, stuffed animal (about his size) and white noise (ticking clock or ipod with soft music) so he can sleep. He's used to cuddling with siblings.
Second: you want to keep him in a room with a family member. DDB's need to be near their family members.
Third: you want to start his food regimen. Are you feeding him what the breeder fed him? If yes, ok. If not, you need to do a slow transition to the new food. Mastiffs are allergic to chicken and grain in kibble. Slow transition is to feed 1/4 of new food with 3/4's of old food for 3-4 days. Transition to 1/2 new and 1/2 old foods for 3-4 days. Transition to 3/4 new and 1/4 old for 3-4 days. Transition to 100% new food. If at anytime he has diarrhea, return to former transition amounts until diarrhea stops.
Fourth: You want to keep the leash on him for a few hours each day while in the house so he gets used to it.
Fifth: Keep him away from dog areas because he hasn't had his 2nd set of shots leaving him prone to getting parvo or other illness. Keep him in your yard and place newspapers down where he will walk on the ground. This is very important!
Sixth: Start basic commands. Train for about 5 minutes per day and slowing increase time. Teach one command at a time. Once they master one command, move onto another command.
DDB's are extremely stubborn and if you get frustrated with them, they will shut down. DDB's do not do well with yelling.
Number one command is sit. Teach him to sit, by placing a treat in front of his head and move it to the back causing him to sit to get the treat. When he sits, tell him good sit and give him the treat.
Second command should be "focus/look" This will help you tremendously when he's over 100 lbs. Put him into sit. With a treat in your hand (let him smell it), put the treat up to your eyes and tell him to look or focus. He may only do this for about 1-2 seconds. As soon as he looks at your eyes, tell him good look or good focus and give the treat. DDB 's do not like to look anyone in the eyes for long because that means a challenge to them. Titan is up to 25 seconds of looking at me.
Other commands to teach is stay, come, leave it and drop it.
Puppies should not do any heavy exercise or walking for the first year. Stairs should be maneuvered while on leash (even in the house) especially going down the stairs. DDB's can be very lazy but they still need to exercise. Puppies should not be walked for more than 15-20 minutes and do your best to avoid heavy running or jumping.
DDB's should not be neutered/spayed until 18 months to 2 years. NO MATTER what the vet says. Early neutering can cause growth problems.
Enjoy your baby! Have lots of patience! The pup will reward you with love and loyalty!
