Territorial 5 year-old GSD

Question
My 5 year old dog, Shadow, has lately become aggressive towards our other dogs.  He constantly follows them around and won't leave them alone, especially when we let them outside to "potty".  I'm pretty sure he's becoming more territorial.  He's never done this before, as he has grown up with the others.  He's not neutered, but is it too late to do so?  And will that help?

Answer
No problem neutering him now, and it should help.  So will strong leadership on your part.  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