A 2.5-year-old miniature dachshund named Otto, presented to the Animal Behavior Clinic at Cummings School of Veterinary Medicine at Tufts University for the sudden onset of aggression to his owners. The aggression consisted of growling, lunging, snapping and biting. Lifting him, attaching a leash and approaching him while resting triggered an aggressive response. He used aggression to guard valued resources, such as his food bowl, long-lasting treats and objects he had taken that did not belong to him. He growled or snapped when petted. He was more likely to attack when he was on an elevated level, such as a sofa or lap. The aggression was intermittent, giving the impression of unpredictability to the owners.
Otto’s referring veterinarian conducted a thorough physical examination. A CBC, chemistry and total T4 were within normal limits. Medical causes of behavioral changes secondary to hypothyroidism, hepatic insufficiency, painful conditions, such as IVDD or orthopedic issues were ruled out.
What is your diagnosis and what treatment would you recommend?
The correct diagnosis is conflict aggression, which is characterized by aggressive behavior directed toward owners in response to a perceived provocation. Triggers can be separated into three categories: resource guarding (e.g., resting places), postural interventions (e.g., lifting, petting, nail trims) and when owner takes on a leadership role (e.g., grabbing the collar, removing from furniture, reprimands, physical punishment). A dog with this problem may behave differently to different individuals in the family. The behavior may also appear unpredictable to owners because it is intermittent. For example, a dog may tolerate being picked up one day and not the next. However, close questioning reveals that there is generally a predictable set of triggers that at least sometimes, will lead to an aggressive response.
This diagnosis used to be called Dominance Aggression. However, our current understanding is that this form of owner-directed aggression is rooted in anxiety, not confidence. Conflict-aggressive dogs are temperamentally bold. However, their anxiety renders them impulsive and reactive toward members of their social group. Studies have shown that conflict-aggressive dogs have lower levels of the transmitter serotonin. (Çakiroǧlu 2007). This condition can be inherited genetically, as seen by its increased frequency in certain breeds, such as dachshunds, chihuahuas, Australian cattle dogs, and others (Serpell 2008). Insufficient early socialization can also predispose dogs to conflict aggression. While the seeds of conflict aggression are planted early in life, it usually manifests at social maturity (9 -24 months of age.)
Important differentials are Irritable Aggression, Fear Aggression and Rage Syndrome (partial complex seizures). Irritable aggression occurs when a dog has a painful medical condition that lowers his or her aggression threshold. Fear aggression is commonly directed at people outside of the dog’s inner circle of family and friends. Rage syndrome occurs in response to a trivial trigger or no trigger at all. It is prolonged and often accompanied by a pre- and postictal behavior change. Dogs may have multiple diagnoses.
Treatment consists of behavioral modification in which triggers of aggression are strictly avoided and steps are taken to improve the owner’s benign leadership position in the eyes of the dog. Changes in diet and exercise are also part of the treatment regimen.
Exercise and Diet:
The owners were instructed to provide Otto with an hour a day of aerobic exercise. They were also told to feed a diet low in protein and free of colorings and preservatives. Exercise and diets lower in protein may help to stabilize serotonin in the brain.
Neutering was recommended as it has been associated with a decrease in aggression. (Tsu 2010)
Avoidance of Conflict and Triggers of Aggression:
The list of triggers was discussed in depth with the owners, and strategies were developed to avoid them. It was explained to the owners that avoidance is therapeutic in that it prevents Otto’s continued sensitization to interactions that he does not like, thereby building trust. The owners were told to no longer permit Otto on laps or furniture and to leave him alone when he rested in his own bed. He should not be lifted up the stairs or into the car. He should not be given any chews or toys he would guard. If he had a stolen object, the owners were instructed to let him have it if it were not dangerous for him or valuable to them. If it were necessary to take it away from him, they were instructed to use a distraction technique such as ringing the doorbell or asking him to go for a walk, then picking it up when he left the room. They were instructed to decrease the frequency and duration of petting sessions. The owner developed a very clever leash and collar combination that could be slipped over his head and fixed onto him from a standing position.
The owners were instructed to strengthen their leadership position by having Otto obey a command before both of his twice daily meals and all food treats. Once his food was prepared, Otto was told one time to sit. If he obeyed, the food was put down instantly and the owner was to walk away. Otto was given 15 minutes to eat. All uneaten food was picked up to prevent guarding. If he did not obey the command to sit, his food was put away and he was not to be fed again until the next meal. If he anticipated the command by sitting before he was told, he was given a different command, such as down. The owners were also instructed to ignore demanding and attention-seeking behaviors.
Fluoxetine (Prozac) was prescribed at 1 mg/kg once daily. Fluoxetine is a selective serotonin reuptake inhibitor that stabilizes mood, increases confidence and decreases reactivity and impulsivity.
Weekly follow-up phone calls were instituted to check in about the program. Each episode of aggression was discussed in detail and the behavioral modification plan was adjusted. The dose of fluoxetine was adjusted once. Otto was neutered.
Three months after the consultation, aggression decreased from one episode per day to one per week. Six months after the consultation, aggression occurred less than once per month.
- Duffy D, Hsub Y, Serpell JA, Breed differences in canine aggression Applied Animal Behaviour Science, Volume 114, Issues 3–4, 1 December 2008, Pages 441–46
- Çakiroǧlu D, Meral Y, Sancak AA, Çifti G, Relationship between the serum concentrations of serotonin and lipids and aggression in dogs Veterinary Record 2007;161:59-61 doi:10.1136/vr.161.2.59
- Hsu Y, Liching Sun L, Factors associated with aggressive responses in pet dogs, Applied Animal Behaviour ScienceVolume 123, Issues 3–4, March 2010, Pages 108–123