Behaviour issues

Question
Hi, I have recently been left in charge of my friends male black lab puppy. He is 8 months old and I have lived with him since he was 8 weeks old. The problem is he is very aggressive and naughty. When he exhibits bad behaviour like growling and barking and even biting he gets worse when you try and repremand him. I am using a training cage at the minute and putting him there for 10 minutes everytime he is naughty but I am quite frequently getting bitten when I try and put him in there if he has reached a hieghtened point of his aggression which can happen very quickly at times if you tell him no or raise your voice in any way, shape or form. He goes on long walks and has a large garden to run around in. Any suggestions on what might be causing this behaviour or how to better control it would be greatly appreciated?

Answer
The key to most behavior problems is approaching things using the dog's natural instincts. Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/

It is possible things may have gone far enough that you will need the help of a private trainer or behaviorist.  Part of it is having a knowledgeable person observe the dog to see what is happening.