aggressive rottie

Question
Hi,
   I have a neutered 19 mo old rottie who is very aggressive towards other dogs(except our little rat terrier) and sometimes people(except anyone who lives in our house). His best bud is my 2 year old. Problem is that I'm very concerned that on a walk he is going to end biting somebody as he does lunge for people, and goes into a completely different state of mind when he sees another dog.
The last trainer he was with recommended a shock collar which seemed to do the trick except the dog knew when the collar was on and would act appropriately at that time.  I am hesitant to get a collar of my own as I've heard this can lead to heightened aggressiveness.  I've tried praise, walking and running for hours before introducing to other dogs and food rewards. Seems nothing is working.  I really love this dog and would hate to give up but I'm really concerned that he is going to hurt someone.  I got him at 6 MOS of age and don't know anything about his parents.  His name is Roscoe and any insight, help, or magic that you can offer would be greatly appreciated. Thanks  

Answer
Hi, First, I must say that I am happy to hear you are continuing to try with your Rottie. Please remember that all trainers are not behaviorists, so if your trainer did not give you the solution you need, look in your area of a canine behaviorist. My husband and I own and train Rotweillers and Dobermans, so I know that they can be a challenge, but the good thing for you is that your dog is young. Have you read about pack leadership and dominance issues?  If not, you should. You can go into some of my listings to other people with aggression/fear issues and find some advice there as well. Walking at least 45 minutes to an hour each day, at the heel, with him wearing a pack will exercise his mind and body. You have a working breed, so they do well if you get a large pack, fill the pockets with water bottles, rice, beans...(I usually use water bottles and a fold up bowl). Equally divide the contents of the pockets so that the pack does not slip from side to side. Change your gaits from a slow walk, quick walk, jog, and back and forth so he gets used to following you. Make lots of quick changes of direction as well. He must realize that you are his pack leader that will provide exercise and direction for him as well as discipline and knowledge. Using a heavy link slip collar up high on his neck will give you good control, and do not use a flexi-lead. You want him walking slightly behind your (preferably) left knee at all times on a relaxed lead, but not allowed to follow his nose all over the neighborhood. Make his sit frequently. If you come across other dogs look past them, stay calm and relaxed, and just walk on. If he decides to jump about and act silly, speed up your pace and once you are past them, make him sit, but do not praise him yet. Teach him that you go in and out of the door first, and he follows. Shock collars have their place in extreme conditions, but you are right, they should not be used as an every day tool. You can let him wear a regular buckle collar or martingale once he is doing well for you. But never leave a slip lead on when the dog is not supervised. I leave a buckle collar on all of our dogs and only put the slip collar on when we are out working or going in public places. Please leave me some feedback and let me know how things are going for you in a week or two. Thank you for writing. Regards, Susan