Best muscle building supplement for a rottweiler dog?

I have a rottweiler dog about 19 months old and he has alot of skin to grow into stll yet. But i wanted to bulk him up. If anyone has any suggestions on exercises and/or supplements so we can reach our goal.

Walk him. Run him. Excersise him properly. Feed a premium diet, and he will naturally build up the muscle he is meant to. Large breed dogs aren't done filling in until 2 or 3 years old. A 19 month old rott is still a puppy, and shouldn't be full grown yet.DO NOT supplement. It's all chemical crap. Junk or steroids, both of which are BAD

A good quality dog food and lots of exercise will do it, but don't overdo the exercise because you can definitely overdo it with a young dog which can give joint problems later. Check with your vet and see if the dog is mature enough to take hard exercise You don't bodybuild dogs. They are what they are, and it's silly to purposely try to bulk him up. He'll get the muscle he gets by using his muscles. Some dogs have what looks like extra skin their whole lives. They don't need to "grow into it". And it isn't "our" goal. It's yours. The dog is fine with his body image.

Exercise. To build his rear muscles, try doing sprints up a hill. Put him in a sit/stay at the bottom of an incline. You walk to the top and call him. Of course, only do this if his recall is good, if not, you sprint up the hill with him. Stairs are a good thing too for building muscles. Have him go up and down some stairs, slowly, one at a time. You doing it with him, holding him back and making him go slow. Get him to sit, then get him to slowly stand up on his hind legs, only, kind of doing a crunch if you will. Mostly, walk him more. He is also now over 18 months old, so you could start road working him without worrying about his hips and elbows. By road work, I mean jogging with you, or get an attachment for your bike, and run him that way while you ride. He is still a pup, and has not matured yet. As someone else mentioned, it does take until they are a minimum of 2 years, possibly as long as 3 years old for them to completely fill out and reach their full potential. I am finding that out with my 2 year old, but then, I do not exercise her as much as I need to. She has more of the couch potato attitude than my 3 year old does. Each dog is different though too. My 3 year old had it all at 9 months old. Whereas my other girl is slowly maturing, and will probably not reach her full potential until she is closer to 3. Another idea for your dog.... put up a kennel run in your yard. In stead of crating him, or even letting him have run of the house when you are at work, put him outside in the kennel run. He will have lots of stimulation that he would not have inside. And, you may find that it helps build muscles because he is actually doing some running in that kennel run. If you do that, however, do not forget to put a roof on it, and also put some kind of flooring down that he can not get up or dig up. Patio blocks work well, but are quite heavy to move. My run is almost complete then my girls will be going outside when I am at work. And, I know I will see great improvement in her body and her attitude. She will become more alert, more active, have more stamina and drive. Crating to me, only tends to hinder the dogs growth, their personality, make them lazy. Anyway, good luck with your boy. Hope I helped. I would not suggest any supplements. I would suggest exercise as the best way to improve your dog's health and overall appearance.

You could ask your vet about a vitamin supplement along with good protein and exercise.

The best overall exercise for a dog is a nice long walk/romp in the woods. The dog exercises all muscle groups as he walks, runs, jumps over fallen logs, goes uphill and down, etc. As others have mentioned, a 19-month old Rotty is still an adolescent. He won't fill out until around 2 1/2 to 3 years. You can use some vitamin supplements, but "bulking up" with artificial substances (think baseball players and body builders) is a really bad idea.