Veterinary study details link between pain and aggression in dogs

A recent study conducted at the Autonomous University of Barcelona confirmed what many in the veterinary community have long known—there's a direct correlation between pain and aggression in dogs. But what effect does a dog's previous behavior have on the intensity or manifestations of aggression?

Researchers at the university's veterinary hospital were determined to find out and developed a retrospective study to examine the relation of pain and aggression, evaluating the circumstances leading to aggression, body posture during the attack, impulsiveness and aggressive behavior before the onset of the pain-eliciting condition.

Twelve dogs were presented for the study, all of which were determined to have aggression triggered by pain. The most common cause of pain among the dogs was hip dysplasia. Additionally, the dogs were classified as having been aggressive before or after the onset of the painful condition. The dogs that were aggressive before had been known to show aggression toward their owners in situations of a competitive nature, such as when the owners removed their food, moved them from a resting position or forced them to do something.

The results of the study showed that dogs that had not been aggressive before the onset of pain were more impulsive to attack, displayed aggression more frequently when handled and assumed a defensive body posture more frequently than dogs that had showed previous aggressive tendencies. The researchers also concluded that the owners of previously non-aggressive dogs were less likely to anticipate an attack, as they were unaccustomed to the behavior. In contrast, animals that were aggressive before the onset of pain had learned behaviors, such as growling, to avoid uncomfortable situations and their owners had likely become conditioned to those behaviors.

Overall, the results suggest that an animal's previous behavior plays a role in the expression of pain-related aggression and reinforces the importance of diagnosing and treating pain to prevent the manifestation of this type of aggression.

The study was published in the March 2012 issue of Journal of Veterinary Behavior: Clinical Applications and Research.