Dog Behavior Problems: Aggression Towards Unfamiliar Dogs Part 2: Treatment

By Ellen Lindell, VMD, DACVB; Debra Horwitz, DVM, DACVB & Gary Landsberg, DVM, DACVB, DECAWBM

Is there a standard treatment protocol for dogs that behave aggressively toward unfamiliar dogs?

One protocol is standard for all types of aggressive behavior: you must create a management strategy that will provide both physical and emotional safety for you, your dog, and the dogs and people you encounter outside the home.

If your dog lunges at other dogs while on leash walks, try to avoid dogs by changing your path or adjusting the time of day you walk your dog. If your dog has shown aggressive behavior while in a group, such as a daycare or a dog park, then do not bring your dog back to a group setting until treatment has been completed.

If you are concerned that your dog might accidentally reach and bite another dog, consider using a basket muzzle. Since your dog will be vulnerable while muzzled and could be injured should another dog attack, it is important to walk only in areas where other dogs will be leashed and cannot bite your dog. (See the handout “Muzzle Training for Dogs” for more information.)

If your dog only shows aggression when dogs get very close, for instance, when a dog tries to sniff her, approach her toy, or get close to you, then, for now, it is important to prevent these interactions altogether. For example, do not allow your dog to greet other dogs on walks—you may need to lure her past with treats if she pulls to meet the dog. You may continue to bring your dog to visit with your friends and relatives, but keep her on a leash and ask your friends to leash their dogs, too, or use a baby gate to ensure your dog has enough space for comfort.

"Identifying triggers for any aggressive response is essential so that appropriate management can be applied."

Identifying triggers for any aggressive response is essential so that appropriate management can be applied. The outcome will be better if your dog is not exposed to these triggers until treatment is complete. Some management strategies may be short-term, and others may be permanent. (See the handout “Dog Behavior Problems – Aggression Toward Unfamiliar Dogs Part 1: Assessment” for more information.)

Before beginning a behavioral treatment program, ask your veterinarian to do a thorough physical exam—your dog could be in pain or have an underlying medical condition contributing to the aggressive response. A veterinary behaviorist should assess your dog if this is not the case. There are many possible causes for aggressive behavior toward unfamiliar dogs. Understanding the motivation behind your dog’s behavior is essential to apply the correct treatment.

How can I prevent my dog from lunging at other dogs on walks?

When walking your dog, use a secure-fitting collar and sturdy leash (see the handout “Collar and Harness Options for Dogs” for more information). A long-term treatment strategy will involve helping your dog relax even when another dog is in sight.

To start, it is helpful to train two behavioral skills:

  • The first is ‘heel’ or ‘walk with me’—your dog can be taught to walk next to you when there are no dogs nearby and eventually when there are dogs in the area. Training always starts at home, in a quiet area with no distractions. Walk forward while holding a treat in your hand so your dog can easily be rewarded while walking beside you. Soon your dog will eagerly assume this ‘heel’ position whenever she sees you start to walk forward with a treat in hand. Once she understands the desired behavior, say ‘heel’ just as she is about to step into the position. Next, try practicing with some distractions.
  • The second conditioned behavior will be ‘sit, stay, relax’. Again, first train in a quiet environment. Encourage your dog to sit and relax in front of or beside you as you deliver treats. Use a calm voice and ensure your dog sits patiently each time you deliver the treat. Work your way up to a calm two minutes—this is enough time for a dog in the street to pass by you. You may use the cue ‘stay, relax’ as she relaxes.

Once the ‘heel’ and ‘sit, stay’ cues have been mastered, you can arrange desensitization and counterconditioning sessions. During these sessions, you can ask your dog to ‘sit, stay, and relax’ when approaching dogs are far enough away that your dog can easily focus on your cues. With each session, the approaching dog may get a little closer until, finally, after many sessions, your dog can sit and relax when the other dog is close enough for you to talk with the other handler. A qualified trainer who understands learning theory and positive reinforcement can help you with these sessions.

Until your dog is ready, if you do encounter a dog on a walk, try to guide your dog off the path. Do not try to train your dog by giving her commands or corrections while she is lunging. Try to stay calm and quiet. Hold the leash steady with just enough tension to keep her from getting away or accidentally biting you. It often helps to stand still rather than continue moving forward, as pulling on the leash can cause frustration and increase the intensity of an aggressive response.

Though you should not use verbal cues until your dog can respond consistently with distractions, you can keep the mood ‘calm’ by using a gentle, cheerful voice when you see a dog approaching—for instance, you can say, “good dog, here comes another lovely dog.” If your dog will take a treat, treat your dog generously until the other dog has passed you by. With some training, you may be able to ask for a 'sit' and reward a relaxed sit stay. Sometimes, it is not possible to stop in place. If you need to move forward to get past a particular dog, try using high-value treats to lure your dog along.

How do I reduce my dog’s fear and anxiety about other dogs?

Fear and anxiety are often treated with desensitization and counterconditioning. It is essential to identify the point at which your dog appears uncomfortable—perhaps your dog puts her ears back, stares, snarls, or attempts to move away during a typical session, your dog might be asked to ‘sit, stay, relax’ while the dog that triggers the response begins to approach yet stays far enough away so your dog can remain relaxed. (See the handout “Introduction to Desensitization and Counterconditioning” for more information.)

Identifying the triggers and context for the fear-based response is important. Your behavior consultant can design a behavior modification program to reduce your dog’s fear over time.

"Identifying the triggers and context for the fear-based response is important."

The pace should be slow so your dog is never frightened during a session. The term ‘threshold’ is sometimes used to describe a dog’s lower tolerance level—in treatment, a dog is purposely kept ‘under threshold’.

How do I stop my dog from behaving aggressively when dogs approach the house or property?

To begin, try to minimize the opportunity for your dog to observe and bark at other dogs passing by the house or yard. The more your dog practices the behavior, the more difficult it will be to change. Indoors, consider using a gate or closing curtains so that the windows with the best street view are blocked. Outdoors, supervise your dog, keeping her on a leash if you expect dogs are likely to pass by. The leash will keep her close to you so that she cannot rush toward the fence barking; while she is near you, you can take advantage of the opportunity to give her treats for remaining quiet.

Behavior modification may involve response substitution. You can teach your dog to move to a specific spot, such as a mat or dog bed, in response to the sight of a passing dog. To start, train the ‘go to spot’ cue when all is calm. (See the handout “Dog Behavior and Training – Teaching Settle and Calm” for more information.)

Use a lure without saying a verbal cue until your dog understands the cue. If your dog notices a dog passing by, quietly take out some delicious treats. Do not get too close to your dog if she is very excited—she could accidentally redirect her aggression toward you. Stand a few feet away, shaking the treats, and lure her to her spot once she notices you. Then, keep feeding her for ‘staying’ quietly until you are certain the other dog is no longer in sight.

Can resource guarding or possessive aggression be treated?

Sometimes, a particular resource is so valuable to a dog that any approach by another dog can trigger an aggressive response. For treatment to be entirely successful, your dog must learn to accept relinquishing valuables, which can be difficult. It may be best to remove valuables before allowing dogs to interact. (See the handout “Possessive Aggression in Dogs” for more information.)

Can predatory aggression or behavior be treated?

If your dog has been diagnosed with predatory aggression or behavior toward other dogs, your dog should be kept on a leash when other dogs, particularly small dogs, are nearby for safety. An attack can occur quickly should a small dog suddenly appear. Treatment might include using response substitution to teach an alternative behavior such as ‘lie down’. However, aggressive behavior can never be entirely eliminated, meaning there is always some risk that the behavior will resurface. Dogs exhibiting predatory aggression or predatory behavior towards other dogs can cause grave injury.

Should I correct my dog when she behaves aggressively toward another dog?

Punishment-based strategies can contribute to an increased intensity of aggression and should be avoided. Whether your dog is exhibiting redirected aggression and is lunging toward another dog, a correction may increase his arousal and frustration. When you correct your dog, you are engaging in a confrontation—now your dog is fighting two fights, and it will be even more challenging for her to relax and recover from the encounter. (See the handout “Why Punishment Should be Avoided” for more information.)

Another concern with using punishment is that when you correct your dog for exhibiting a lower-level signal, such as a growl, snarl, or snap, you teach your dog to abandon safe and valuable communicative signals. Your dog will instead use stronger signals, such as lunging and biting. (See the handout “Canine Communication – Interpreting Dog Language” for more information.)

Is there a medication that can help the treatment program?

Treatment for inter-dog aggression toward unfamiliar dogs always requires behavior modification. If your dog has been diagnosed with anxiety, hyperreactivity, or frustration intolerance, your veterinary behaviorist may suggest adding medication to the treatment program. When used appropriately, medication can allow an anxious or frustrated dog to learn and reduce the intensity of her aggressive response. Most often, an SSRI is selected for the baseline medication. However, the veterinary behaviorist uses many factors, including your dog’s specific medical and behavior profile, to determine which medication suits your dog best. (See the handout “Behavior Counseling – Medications” for more information.)

"When used appropriately, medication can allow an anxious or frustrated dog to learn and reduce the intensity of her aggressive response."

How can I prevent my dog from becoming aggressive with other dogs?

Though all aggressive behavior cannot be prevented, early socialization can be helpful. Socialization involves deliberate exposure to friendly dogs and should only be done if your puppy appears neutral or friendly as well. If your puppy or adult dog is already exhibiting signs of fear or aggression when other dogs are nearby, all attempts to socialize through further exposure should be discontinued until a behaviorist can be consulted.

Reward-based training may also help reduce the risk of your dog developing aggression toward other dogs. During training, you and your dog will learn to communicate with each other. Your dog will learn to happily follow your cues, allowing you to easily guide her away from another dog if needed.

It is important to note that even well-socialized and well-trained dogs can develop aggression toward other dogs.

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