on leash

Question
my dog is 11mths old he is a big gsd and usually very good except when walking on a lead and he he see another dog on a lead he goes ballistic barking wanting to go and say hello he isn't nasty but i try say leave and keep walking but he doesn't listen.

Answer
I would suggest several things starting with taking over as top dog.  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/  For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm

And counter to what an obedience instructor likely will say, I would switch to a head collar.  The leading brands are Promise,  Haltie, and Gentle Leader.  They have a strap going around the dogs nose looking something like a muzzle.  They work by pulling the dogs head around.  No other way gives you such great control with so little force.  The prong collar is now a  dangerous relic of value only for its macho looks.  Do not consider using one without hands on instruction from somebody with plenty of experience with them.

Finally, he needs his dog socialization.  It would be great if you have friends or family that you can let the dogs play in a fenced area.  Otherwise, try a dog park.  Where does he spend his day, at home alone?  Look into doggy day care.  And don't worry if the play gets a little active.  Here is a link to my dog and a friend's dog we were sitting, http://www.photolocker.net/images/Labman/gretchenandellaplaying.jpg