Vol. 2 No. 1 (2016)
Case Report

Canine aggression toward a new puppy in the household

Published 2016-03-30


  • behavior problem,
  • dog,
  • canine aggression,
  • puppy introduction


A 5-year-old spayed female pure breed German Shepherd dog was referred to a veterinary behaviorist because she was aggressive toward a 2-month-old male pure breed Czechoslovakian Wolf dog. The puppy was recently introduced in the household. The German Shepherd was previously treated because of a social phobia diagnosis.

The detailed history and the behavioral evaluation supported the presumptive diagnosis of territorial and protective aggression, which are often included in the same category, and predatory aggression. Predatory behaviors were unexpectedly discovered during the consultation and classified as predatory aggression. The adult dog didn’t show aggressive behaviors toward familiar or unfamiliar people, but she was reactive toward other dogs. The puppy showed a normal age-related behavior.

The therapeutic strategy included safety recommendations, environmental changes, behavior modification and training sessions with professional trainers team support, drug therapy for the German Shepherd dog (fluoxetine, 1 mg/kg q 24 hours). Territorial, protective and predatory aggression was initially controlled. Finally the adult accepted the puppy as a pack member and improved her relationship with other dogs. This case report offers the opportunity to remind the importance of an appropriate procedure for the introduction of a new dog in the household to prevent behavioral disorders.