Risk factors for human-directed canine aggression in a referral level clinical population.

Risk factors for human-directed aggression were investigated using retrospective analysis of data from a referral-level clinical behaviour population in the UK. A sample of 200 cases involving human-directed canine aggression and 200 control cases involving no instance of human-directed aggression were selected at random from a population of 746 cases. The final model suggested that clinical cases with human-directed aggression were significantly younger than those presenting with other undesired behaviours (P=0.008) and that male dogs were 1.4 times more likely to be aggressive towards human beings than female dogs (P=0.019). Dogs were 1.7 times more likely to be aggressive towards people if they had attended more than five puppy classes than if they had never attended puppy class (P=0.015) and that dogs were 2.8 times more likely to be aggressive towards human beings if there was another dog between 0 months and 24 months of age in the home (P=0.004). These factors only account for 7 per cent to 10 per cent of the variance between the human-directed aggression population and the control population, but factors such as attendance at puppy classes and numbers of dogs in the household suggest the need for longitudinal studies to investigate temporal relationships.

Inter-dog aggression in a UK owner survey: prevalence, co-occurrence in different contexts and risk factors.

Aggression between dogs is common and can result in injury. The aims of this study were to estimate prevalence, evaluate co-occurrence with human-directed aggression, and investigate potential risk factors, using a cross-sectional convenience sample of dog owners. Aggression (barking, lunging, growling or biting) towards unfamiliar dogs was reported to currently occur, by 22 per cent of owners, and towards other dogs in the household, by 8 per cent. A low level of concordance between dog and human-directed aggression suggested most dogs were not showing aggression in multiple contexts. Aggression towards other dogs in the household was associated with increasing dog age, use of positive punishment/negative reinforcement training techniques, and attending ring-craft classes. Aggression towards other dogs on walks was associated with location of questionnaire distribution, owner age, age of dog, origin of dog, dog breed type, use of positive punishment/negative reinforcement training techniques and attending obedience classes for more than four weeks. In both, the amount of variance explained by models was low (<15 per cent), suggesting that unmeasured factors mostly accounted for differences between groups. These results suggest general characteristics of dogs and owners which contribute to intraspecific aggression, but also highlight that these are relatively minor predictors.