Assessment, management, and prognosis of canine dominance-related aggression

Aggression directed toward owners is a common complaint, and one that causes a great deal of emotional conflict. Assessment and treatment of this disturbing behavior problem must address owner safety as well as realistic expectations for improvement. Relatively mild aggression may be treated with a combination of prevention of injury, increased structure in the home, and safe control of the dog, including obedience training to reward the dog for deference to the owner. Disproportionately severe or unpredictable aggression is less likely to respond to treatment. Mounting evidence exists that aggressiveness is genetically and neurobiologically driven. Research in other species, and early research in the dog, suggest that aggression may be reduced by drug therapy to modify brain neurochemistry. Such treatment is not a cure, however, and should be paired with a lifelong, systematic program of safety and control in the home.

Comparison of cerebrospinal fluid monoamine metabolite levels in dominant-aggressive and non-aggressive dogs

Aggression has been shown to be related to reduced serotonergic activity in humans and non-human primates, and in rodents. We now studied the relationship between cerebrospinal fluid (CSF) monoamine metabolites and canine aggression in 21 dominant-aggressive dogs (Canis familiaris) and 19 controls. The diagnosis of dominance-related aggression was based upon a history of biting family members in contexts associated with dominance challenges. Post-mortem CSF 5-HIAA, MHPG and HVA were measured by high-performance liquid chromatography using electrochemical detection. Concentrations of CSF 5-HIAA (P = 0.01) and HVA (P < 0.001) were lower in the aggressive group (median values: 5-HIAA 202.0 pmol/ml; HVA 318.0 pmol/ml) than in controls (5-HIAA 298.0 pmol/ml; HVA 552.0 pmol/ml). No differences were noted in CSF MHPG levels. Differences in 5-HIAA were maintained after controlling for breed and age of dogs, but HVA differences may have been breed-dependent. Lower levels of 5-HIAA (P = 0.02) and HVA (P = 0.04) were found in the subgroup of aggressive dogs with a history of biting without warning (5-HIAA 196.0 pmol/ml; HVA 302.0 pmol/ml) compared to dogs that warned (5-HIAA 244.0 pmol/ml; HVA 400.0 pmol/ml). This study suggests that reduced serotonergic function is associated with aggressive behavior and impaired impulse control in dogs, a finding that is consistent with observations in primates, and suggests that serotonin modulates aggressive behavior throughout mammals.

Comparison of cerebrospinal fluid monoamine metabolite levels in dominant-aggressive and non-aggressive dogs

Aggression has been shown to be related to reduced serotonergic activity in humans and non-human primates, and in rodents. We now studied the relationship between cerebrospinal fluid (CSF) monoamine metabolites and canine aggression in 21 dominant-aggressive dogs (Canis familiaris) and 19 controls. The diagnosis of dominance-related aggression was based upon a history of biting family members in contexts associated with dominance challenges. Post-mortem CSF 5-HIAA, MHPG and HVA were measured by high-performance liquid chromatography using electrochemical detection. Concentrations of CSF 5-HIAA (P = 0.01) and HVA (P < 0.001) were lower in the aggressive group (median values: 5-HIAA 202.0 pmol/ml; HVA 318.0 pmol/ml) than in controls (5-HIAA 298.0 pmol/ml; HVA 552.0 pmol/ml). No differences were noted in CSF MHPG levels. Differences in 5-HIAA were maintained after controlling for breed and age of dogs, but HVA differences may have been breed-dependent. Lower levels of 5-HIAA (P = 0.02) and HVA (P = 0.04) were found in the subgroup of aggressive dogs with a history of biting without warning (5-HIAA 196.0 pmol/ml; HVA 302.0 pmol/ml) compared to dogs that warned (5-HIAA 244.0 pmol/ml; HVA 400.0 pmol/ml). This study suggests that reduced serotonergic function is associated with aggressive behavior and impaired impulse control in dogs, a finding that is consistent with observations in primates, and suggests that serotonin modulates aggressive behavior throughout mammals.

Risk factors for behavior-related euthanasia among dominant-aggressive dogs: 110 cases (1989-1992)

Establishing a prognosis for dogs with dominance-related aggression is difficult. Some dominant-aggressive dogs respond well to treatment; others continue to be serious risks for their owners. A study was performed to identify characteristics of dominance-related aggression and to identify risk factors associated with whether the aggressive behavior led to euthanasia. Medical records of 110 dogs with dominance-related aggression were examined retrospectively; characteristics of owner-directed aggression and eventual outcome of the dogs were recorded. By means of logistic regression, 2 different models were found to describe the association between behavior characteristics and outcome. In the first model, severe aggression in response to benign dominance challenges and body weight > 18.2 kg were associated with outcome. In the second model, unpredictability of aggression and a history of being purchased were associated with outcome. We concluded that dominance-related aggressive behavior can be subclassified according to severity and type and that outcome (ie, euthanasia) may be predictable in some cases.

Friendliness to humans and defensive aggression in cats: the influence of handling and paternity

This study was undertaken to examine and reduce the stress and aggressiveness associated with fear of handling in laboratory cats (Felis sylvestris catus). Thirteen litters of kittens from a specific pathogen-free breeding colony were divided into three treatment groups: two were early weaned, removed from the colony and caged individually with or without handling up to 8 weeks of age, and the third served as a control group, removed from the colony just before testing. Behavior tests measuring degree of friendliness to humans and response to physical restraint were performed at ages 8, 12, 16, and 20 weeks. Serum cortisol concentrations were measured after each test. Results indicate that litter and sire influenced tractability but that handling or individual caging of kittens did not. Posttest serum cortisol concentrations were below normal adult levels in most kittens, including those reacting fearfully during testing and aggressively during restraint, and, therefore, are not a reliable indicator of stress in juvenile cats.