Some dogs behave aggressively towards other dogs or people when they are on a leash. Some of these pets behave aggressively only in this situation, and some behave aggressively in other situations as well.
Leash aggression is best understood as a combination of a few basic types of aggression: territorial and protective aggression, resource-guarding aggression (the "resource" being the leash holder) and, in some cases, fearful aggression. While one type of aggression might be a larger part of leash aggression than another type for any individual dog, the management of leash aggression is similar for all dogs.
MANAGEMENT AND TREATMENT
EXAM AND DOCTOR CONSULT We believe it is very important to begin the management and treatment process with a physical exam and doctor consultation. This allows us to tailor the initial plan for the individual dog, and establishes a baseline for comparison as treatment progresses. It also gives us the opportunity to decide on whether or not medication might play a role.
TAKING CONTROL OF THE ENVIRONMENT Each time a dog behaves aggressively on a leash it is powerfully reinforcing its own bad behavior, so the first and most essential step in solving the problem is to not place the dog in situations where it might behave this way. This might require changing the time of day and / or location of walks to avoid having the dog see potential targets.
Some dogs can see the potential target and not become aroused as long as the target is a safe distance away. This distance will vary from dog to dog, and it is vital that the dog not be allowed inside this safe distance in order to prevent it from behaving aggressively. Make a note of this distance and a list of all the dog's targets at the start of management and treatment.
Many dog-owners walk their dogs with the hope that they will have the opportunity to interact with other dogs and people. Another reason for maintaining a safe distance is to prevent such an owner from innocently bringing their dog too close to a leash aggressive dog.
Another potentially valuable step in taking control of the environment is to use proper walking equipment. Do not use a retractable leash; the leash should have a fixed length of 6 feet or less, and should have a handle that is easy to grip and hold securely. A head halter (Gentle Leader) is also a good idea.
Other management might be needed. For example: A leash-aggressive dog might behave differently for different walkers; the person for whom the dog is most-badly behaved should not be allowed to walk the dog until the dog has completed basic training. A leash-aggressive dog is more likely to behave badly if it is walked along with housemate dog(s) than if it is walked alone; it is also very difficult to engage the dog in basic training when another dog is in close proximity.
Some owners notice that their dog appears to be non-aggressive off leash. Simply leaving the dog off leash is definitely not a safe or acceptable way of managing leash aggression. Remember, leash aggression is a mixture of territorial, protective, resource-guarding, and possibly fearful aggression. Removing the leash might relieve one of these types of aggression, but not all of them. It would be very easy for an off-leash leash-aggressive dog to end up in another situation where it becomes aggressive.
TRAINING Only when the dog's leash environment is under the owner's control should training to correct the problem begin. Training should be by positive reinforcement only; punishment evokes fear, and can only make the problem worse.
Training begins with teaching the dog the basics; come, sit, down, and watch. For detailed instructions refer to our YVCipedia articles TRAINING BASIC COMMANDS, STRUCTURED INTERACTIVE TRAINING (SIT) and TEACHING WATCH. If you will be using a head halter the dog must be trained to wear that as well. (You can find head halter training instructions at http://www.petsafe.net/media/manuals/gl-gentle-leader-headcollar-manual.pdf and http://www.aspca.org/pet-care/virtual-pet-behaviorist/dog-behavior/introducing-your-dog-head-halter.)
Once the dog is performing these basics nine out of ten times it is asked then it can be gradually reintroduced to situations where it previously behaved aggressively. "Gradual" is the key: expect this part of the process to take a few weeks at the least. It may also be necessary to stage the situation using the help of other dog owners.
The dog is initially brought close to, but not within, the distance at which it previously acted aggressively. Some of the commands that have been trained are given to assure that the dog is calm and focused on the owner, not the target. The walk then continues in the opposite direction, not towards the target.
When the dog behaves calmly in this situation for at least a few days in a row, the distance is closed to within the distance at which it previously behaved aggressively and the process is repeated. Each time the distance is made smaller the dog should respond to the trained commands and remain non-aggressive; if it behaves badly then the distance should be increased back to the point where it last behaved non-aggressively.
MEDICATION Anxiety is part of the leash aggression problem for some dogs; for these pets a daily antianxiety medication can make the training and desensitization process go much more smoothly. Once the process is complete the medication can be gradually withdrawn. The medications that we use are prescription drugs; an exam and consultation with a doctor is needed prior to starting the pet on one.