from this website http://www.ddfl.org/behavior/dominance.htm

Dealing With Dominance In Dogs
Copyright 2000. Dumb Friends League. All rights reserved.

In order for your home to be a safe and happy place for pets and people, it’s best that the humans in the household assume the highest positions in the dominance hierarchy. Most dogs assume a neutral or submissive role toward people, but some dogs will challenge their owners for dominance. A dominant dog may stare, bark, growl, snap or even bite when you give him a command or ask him to give up a toy, treat or resting place. Sometimes even hugging, petting or grooming can be interpreted as gestures of dominance and, therefore, provoke a growl or snap because of the similarity of these actions to behaviors that are displayed by dominant dogs. Nevertheless, a dominant dog may still be very affectionate and may even solicit petting and attention from you.

You May Have A Dominance Issue With Your Dog If:

• He resists obeying commands that he knows well.
• He won’t move out of your way when required.
• He nudges your hand, takes you’re arm in his mouth or insists on being petted or played with (in other words, ordering you to obey him).
• He defends his food bowl, toys or other objects from you.
• He growls or bares his teeth at you under any circumstances.
• He won’t let anyone (you, the vet, the groomer) give him medication or handle him.
• He gets up on furniture without permission and won’t get down.
• He snaps at you.

What To Do If You Recognize Signs of Dominance In Your Adult Dog
If you recognize the beginning signs of dominance aggression in your dog, you should immediately consult an animal behavior specialist. If the dog is an older puppy or adult, and there is any risk of the dog biting you, then physical punishment may be dangerous. Getting physical with a dominant dog may cause the dog to intensify his aggression, posing the risk of injury to you. With a dog that has shown signs of dominance aggression, you should always take precautions to ensure the safety of your family and others who may encounter your dog by:

• Avoiding situations that elicit the aggressive behavior.
• Supervise, confine and/or restrict your dog’s activities as necessary, especially when children or other pets are present.
• When you’re outdoors with your dog, use a "Gentle Leader" or muzzle.
• When you’re indoors with your dog, control access to the entire house by using baby gates and/or by crating your dog. You can also use a cage-type muzzle, or a "Gentle Leader" and leash, but only when you can closely supervise your dog.

Dominance aggression problems are unlikely to go away without your taking steps to resolve them. Treatment of dominance aggression problems should always be supervised by an animal behavior specialist, since dominant aggressive dogs can be potentially dangerous.

The following techniques (which don’t require a physical confrontation with your dog) can help you gain some control:

• Spay or neuter your dog to reduce hormonal contributions to aggression. NOTE: After a mature animal has been spayed or neutered, it may take time for those hormones to clear from the system. Also, long-standing behavior patterns may continue even after the hormones or other causes no longer exist.
• "Nothing in Life is Free" is a safe, non-confrontational way to establish your leadership and requires your dog to work for everything he gets from you (see our handout: "Nothing in Life is Free"). Have your dog obey at least one command (such as "sit") before you pet him, give him dinner, put on his leash or throw a toy for him. If your dog doesn’t know any commands or doesn’t perform them reliably, you’ll first have to teach him, using positive reinforcement, and practice with him daily. You may need to seek professional help if your dog is not obeying each time you ask after two to three weeks of working on a command.
• Don’t feed your dog people food from the table and don’t allow begging.
• Don’t play "tug of war," wrestle or play roughly with your dog.
• Ignore barking and jumping up.
• Don’t allow your dog on the furniture or your bed, as this is a privilege reserved for leaders. If your dog growls or snaps when you try to remove him from the furniture, use a treat to lure him off. Otherwise, try to limit his access to your bed and/or furniture by using baby gates, a crate, or by closing doors.
• Always remember to reward good behavior.
• Consult your veterinarian about acupuncture, massage therapy or drug therapy.
• Obedience classes may be helpful in establishing a relationship between you and your dog in which you give commands and he obeys them (be sure to choose a trainer who uses positive reinforcement methods). Obedience classes alone, however, won’t necessarily prevent or reduce dominance aggression.

A Note About Children and Dogs
From your dog’s point of view, children, too, have a place in the dominance hierarchy. Because children are smaller and get down on the dog’s level to play, dogs often consider them to be playmates, rather than superiors. Small children and dogs should not be left alone together without adult supervision. Older children should be taught how to play and interact appropriately and safely with dogs; however, no child should be left alone with a dog who has displayed signs of aggression.

Why Our Behavior Helpline Can’t Help
While it’s sometimes possible to successfully resolve aggressive behavior problems related to dominance, this is not a process that can be done by our Behavior Helpline staff and volunteers. Very detailed questioning in order to obtain a complete behavioral history, plus direct observation of your pet in his own environment, is necessary before recommendations to resolve the problem can be made. Our Behavior Helpline is limited to telephone assistance (see our handout: "When the Helpline Can’t Help").