Treat or euthanize? Helping owners make critical decisions regarding pets with behavior problems


Concrete steps you can take in reaching a decision.

Behavior problems are frequently cited as a major cause of relinquishment or euthanasia of companion animals.1-3 But owners who receive competent and efficacious assistance in dealing with their pets' behavior problems may be more likely to preserve the human-animal bond and, thus, retain the animals. Indeed, studies show that pets receiving routine veterinary care and dogs that have attended obedience classes are more likely to be retained in the home.2,4

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Still, behavior problems can be frustrating, emotionally taxing, and often dangerous to the animal or those around it. These problems can also pose a substantial financial burden in terms of potential liability and resources to attempt to correct the problems. Controlling or resolving a behavior problem is typically not easy and, in some cases, is too risky for certain family situations.


Owners of pets with behavior problems have four possible solutions:

1. Live with the problem as it is.

2. Rehome the pet to a more suitable environment.

3. Attempt to rehabilitate the pet to an acceptable level.

4. Euthanize the pet.

Living with a behavior problem is hardly a satisfactory solution. And rehoming or relinquishing a pet often poses additional challenges.

A client who has decided that a pet can no longer stay in the home often wants to send it to a different home, to the proverbial "farm in the country" or to a sanctuary. But rehoming animals with bite histories, or cats with inappropriate elimination, is generally difficult and, with the former group, fraught with ethical and legal constraints. Potential owners often adopt animals out of pity, not understanding the severity of the problems they are inheriting. Many adopters assume their love and empathy for an animal will translate into automatic appropriate behavior on the animal's part. ("He just needs love, and he'll be fine.") Moreover, many rescue groups will not take in dogs with bite histories because of legal liability if the dog bites someone in the new home.

Realistically, rehabilitation or euthanasia is the only practical option in many situations. In this article, I focus on the factors that may influence owners' decisions to rehabilitate or euthanize pets with behavior problems, with an emphasis on pets with aggression or anxiety disorders.

While the level of attachment an owner has to his or her pet varies, even those owners who appear to have little attachment can find it difficult to decide to euthanize an animal. You should never underestimate an owner's emotional attachment to an aggressive animal, even if the owner is the target. Euthanasia is a personal and permanent intervention, and this procedure should never be recommended lightly. The advances in behavior therapy over the past decades are sizeable. If owners have any inclination to pursue therapy or if they are having difficulty deciding whether to treat, referral to a credentialed behavior specialist should be offered.

Because many variables affect the development and maintenance of behaviors, outcome predictions for behavior problems are often less reliable than they are for medical issues, making it difficult to give owners solid prognostic information. Each animal with a behavior problem is a case study of one. The factors that affect the risk:benefit analysis are unique to each situation. Factors that must be evaluated before making critical decisions include those related to the client, the animal's environment, the animal itself, and the behavioral presentation.


Owner perceptions

A client's perception of the animal and the issue is an important factor. How the client feels about the pet, the problem, and the likelihood of the problem's improving will affect his or her dedication to a behavior modification program. If the owner has decided the problem cannot be fixed, the outcome is generally unsatisfactory even if the owner seeks referral. A preexisting defeatist attitude will sabotage the behavior modification program even if the problem is amenable to change. Careful counseling with these clients will often resolve many of their doubts and turn the clients into dedicated participants.

Sometimes warring factions exist in the home with regard to how the animal and the problem should be handled. This family divisiveness can appreciably reduce the effectiveness of any program implemented. This issue should be openly discussed when assisting clients in making a decision.

It is important to know whether the client is afraid of the pet and whether anyone in the home has given an ultimatum. Both situations generally indicate a lower prognosis for success if the client elects to try to work through a behavior modification program.

Finances and time

A significant limiting factor to success is the client's resources: financial, emotional, and temporal. Working through a serious behavior problem requires repeated contact with a veterinarian, veterinary behaviorist, or qualified trainer. Few problems can be resolved in one visit, particularly when dealing with anxiety or aggression disorders. The client must be able to dedicate enough training time to the issue and also have the emotional fortitude to persist through the ups and downs of the program and the opinions and perceptions of friends, family, and outsiders.

Physical or emotional limitations

Clients may also have physical or emotional issues that influence their ability to implement a program successfully. In discussing an animal's prognosis, pay careful attention to whether children or seniors are in the home, as well as any individuals who have substance abuse disorders or mental disorders that can create chaotic or unpredictable behavior. In my experience, the presence of family members with such disabilities generally portends a poorer prognosis, particularly in aggression cases. Similarly, senior citizens may have physical limitations that affect their ability to control large or unruly dogs. That puts the senior at risk of injury in the event the dog pulls the owner over, and it places the public at risk if the dog escapes the owner's control. If you and the owner cannot find an effective way to allow the owner to control the dog physically, the prognosis declines.


The environment plays an important role in the onset, maintenance, and resolution of behavior problems. Environmental stimuli are major factors in reinforcing or punishing behavior. For example, each time a territorially aggressive dog barks out the window at a passerby, the dog is reinforced for the aggressive response when the passerby disappears from view. If the owner cannot limit this behavior, especially when the dog is left alone, the prognosis for resolution is lessened because of the dog's continued rehearsal (and concurrent reinforcement) of the behavior.

Noteworthy environmental features include the presence of other animals, which may contribute to the problem; children or senior citizens in the home, who may be targets of aggression or may inadvertently undermine the behavior modification process; and the layout of the home and property. The owner must be able to control the environmental impact. If the owner cannot control the pet's exposure to trigger stimuli to any degree, then the prognosis for improvement will be poor.

Routine care issues are also important. What options are available to the client for walking a dog for exercise and elimination? How does the pet behave in the car? Are there other animals in the home that also have behavior problems or whose behavior in some way contributes to the patient's issues? For example, in multicat households, I often find that more than one cat is spraying—one cat sprays and then another sprays in response. Each animal must be included in the training process, and the more animals, the greater the burden of work for the family.


Behavior is, thankfully, malleable. However, certain patient characteristics make altering a behavior easier or more difficult.


A patient's size will affect the owner's ability to control the animal and may impact the severity of an injury the animal could inflict. Large dogs are at greater risk of euthanasia for aggression.5 That is not necessarily because larger dogs are more aggressive than smaller dogs but because larger dogs have the potential to inflict greater damage when they do bite.


The patient's signalment will also factor into the situation—sometimes merely because of public perception. The risk of working with notorious breeds such as pit bulls, rottweilers, Doberman pinschers, or German shepherds can be greater than with other breeds because the public is frequently less forgiving of misbehavior by these breeds. The owner of a biting pit bull may be more likely to be sued than the owner of a biting golden retriever. Remember also that breed predispositions for behavior traits may influence treatment steps. For example, herding breeds often chase and nip at people and are reactive to other fast-moving stimuli.

Dog bite studies indicate that intact male dogs generally account for more bites than dogs of other reproductive statuses.6,7 Admittedly, this may be in part because owners of intact male dogs may be less likely to contain or train their dogs than owners who take steps to alter their dogs.

Older animals may suffer from medical issues and brain aging that can complicate treatment steps. Serious behavioral disorders in very young animals often indicate congenital or genetic contributions and may indicate a poorer prognosis in some situations.


Genetic and environmental influences are intricately intertwined. Research in a variety of species and a variety of fields shows genetic expression can be altered with environmental experience8-10 ; however, the animal's genetic template is set and will influence the types of behaviors expressed as well as the approach to resolving them. Pets that have various types of developmental or genetic disorders (e.g. deafness, impulse control disorders) often have a poorer prognosis because the rehabilitation process can be longer and more arduous. In my experience, working with animals with such disabilities often requires a higher skill level on the part of the owner and assistance from a more educated behavior professional.

Developmental period

The pet's developmental period, especially the socialization experience, is a key influence on future behavior.11-13 Certain training during this time can greatly reduce the likelihood of behavior problems; other training practices will induce or worsen certain behavior issues. Training and puppy raising methods that emphasize "dominance theories" and confrontational techniques damage the owner-pet relationship and can increase biting and aggressive responses toward owners.14,15 I have seen a number of dogs develop noise phobia and fear of people in direct response to the training philosophy of one currently popular training franchise. This method involves yelling at the dog and throwing chains in the dog's direction to startle or scare the dog into stopping the undesirable behavior.

As with people, developmental changes during an animal's juvenile and adolescent period have a notable impact on the animal's interaction with its environment and, thus, its behavior. This period is the most trying time when raising a pet and a time when most owners reach the limits of their knowledge and fall short of their obligations as responsible pet owners. Poorly socialized pets may pose a greater challenge for rehabilitation.

Medical history

The pet's medical history, including the diet, supplements, and medications it is receiving, is important to know because these things will affect its behavior.16-22 Certain conditions, diets, and medications may limit the success of a program or may facilitate success. For example, gastrointestinal disorders may complicate resolution of inappropriate elimination disorders. Dietary restrictions for animals with food allergies can make training programs more challenging in terms of finding useful reinforcers and adequate foraging enrichment activities.


Behavioral elements are the most important of the factors because the characteristics of the behavior problem determine how important the other factors will be in the resolution of the issue.

An educated decision regarding a pet's life cannot be made without a thorough description of the problem behavior. What is the problem? What is the frequency and intensity of the behavior? Identifying the predictability of the problem is essential. Owners often report that a problem behavior is unpredictable, but with careful questioning, you can often determine that the problem is highly predictable in relation to when it will occur and what triggers it. When the behavior will not occur may be less predictable, but this information is equally important. Does the behavior pose a danger to people or other animals? Is the animal self-injurious? Determine how many triggers there are for the behavior and, in the case of aggression, how many targets—these are not always the same. For example, a dog may exhibit aggressive behavior in response to loud noises, such as lawn equipment, garbage trucks, or motorcycles. The dog may direct its aggression only toward these items or may redirect onto nearby animals, people, or objects.23,24 The targets may be specific (e.g. only one particular dog or person) or may be more random (whatever or whomever happens to be nearby).

Bite threshold and inhibition

With respect to aggressive animals, two important factors to note are the bite threshold (how easily is the animal triggered to use its mouth?) and bite inhibition (when the animal does bite, how severe is the injury?). Animals that show frequent aggression but do little to no damage are often much better candidates for rehabilitation than animals that bite infrequently but do considerable damage when they do bite. In general, the animal's next bite is likely to be similar in severity to the previous bites. An animal that consistently injures its target severely enough for emergency treatment poses a greater risk, in part, because owners consider these situations more concerning.25

It is not necessarily true that a dog's bite severity will escalate over time. The bite severity depends in part on the animal's bite socialization (did the animal have the opportunity to learn mouth control when it was young?), the animal's physiologic status, and the behavior of the victim (did the victim pull away and, thus, inadvertently increase the severity of the injury?). Additionally, the context of the episode is important in assessing the future risk and predictability of injury. The degree of apparent provocation in relation to the severity of the resultant injury may also help determine the extent of behavioral pathology. For example, a history of prolonged, multiple bite attacks in response to a seemingly innocuous interaction such as looking at a resting dog while walking past it supports the diagnosis of what some authors label impulse control aggression.26,27 In my experience, the animal's age may influence the bite threshold. Similar to people, adolescent animals often exhibit higher levels of impulsivity and reactivity.28,29

It is a fallacy that once an animal bites, it will always bite again. There are numerous case examples of dogs or cats that have bitten once and then never again. The predictability of the aggression and the level of warning the animal shows before escalating to biting should also be evaluated and considered when making a prognosis—a predictable and prolonged warning phase generally portends a better potential for therapy.


Take a complete and thorough history. Physically examine and interact with the animal as much as safety allows. Evaluate the owner's relationship with the animal and how the owner and the pet interact with each other. List the favorable and unfavorable prognostic factors (see Treat or euthanize? Putting it all together: Prognostic indicators).

If a client is unsure whether he or she can implement a plan but does not want to euthanize the animal, set a finite treatment goal. Have the client dedicate two to four weeks to the program. At the end of that period, evaluate the situation. How hard was it for the client to implement the necessary safety management steps? How much time was the client able to spend on the training exercises? How stressful was it for the client to live within the bounds of the program? Does the client feel he or she could maintain that intervention long term? Was there any change in the animal's behavior during that time? Was it better or worse or some of both? The answers to these questions will help the client to decide whether to push on for another set time frame or to stop the program and euthanize the pet.

Give clients permission to elect euthanasia without judgment, especially in cases in which the patient poses an injurious risk to other animals and people. Take into consideration the patient's welfare as well. Animals that are showing frequent anxiety or aggression are living highly stressful lives.


Euthanasia is a personal decision and also a permanent one. Clinicians should never make snap judgments (e.g. all biting rottweilers should be euthanized) that result in the end of a pet's life. Dramatic changes in an animal's behavior are often possible when owners are willing to commit to a behavior modification program. This option should always be presented to owners, including the option of referral to a behavior specialist.

Lore I. Haug, DVM, MS, DACVB

Texas Veterinary Behavior Services

2627 Cordes Drive

Sugar Land, TX 77479


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