Behavioural testing based breeding policy reduces the prevalence of fear and aggression related behaviour in Rottweilers
Behavioural testing allows to exclude dogs that are fearful and aggressive from the breeding population, but relatively little is known about the effectiveness of such strategies in practice.
From 2001 till 2009 parent purebred Dutch Rottweilers had to pass the Socially Acceptable Behaviour (SAB)-test for their offspring to obtain a pedigree certificate. We evaluated if this breeding policy of excluding fearful and aggressive Rottweilers, as diagnosed by the SAB-test, indeed reduced the prevalence of fear and aggression in the Dutch Rottweiler population.
Owner-reported assessments of their dogs' behaviour were compared between groups of Rottweilers with or without pedigree certificates, assuming the Rottweiler look-a-likes to represent the control condition of no breeding policy regarding fear and aggression. A total of 822 Rottweiler owners filled out the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) on problem behaviour, including 7 behavioural categories related to fear and aggression.
Problem behaviour prevalence and explanatory factors were investigated by multivariable logistic regression.The prevalence of Stranger-directed fear (P. <. 0.05) and Non-social fear (P. <. 0.01) was lower in the group of pedigrees than in the group of look-a-likes, with a same tendency for Stranger-directed aggression (P = 0.056). Analysing the combined C-BARQ scores for the behaviour categories that are assessed with the SAB-test, namely Stranger-directed aggression, Dog-directed fear/aggression, Stranger-directed fear and Non-social fear, revealed that one sixth of the pedigree Rottweilers showed these behaviours compared to one third of the look-a-likes (P. <. 0.0001).
Strong associations were found between Stranger-directed aggression and Dog-directed fear/aggression (P. <. 0.001) or Social Fear (P. <. 0.001), indicating the role of fear in aggression towards unfamiliars. The association between Stranger-directed aggression and chase proneness (P. <. 0.01) seems to illustrate how different motivations may underlie a same manifestation of aggression. Familiar dog aggression associated with Owner-directed aggression (P. <. 0.001), implicating that such aggressions may have do with conflicts over status.
Found associations between types of fear/aggression will have in part reflected shared underlying causes, and reflect the known comorbidity of problem behaviours. Their associations with dog and/or owner characteristics indicated several possible risk factors for fear/aggression. However, associations with common risk factors like sex and reproductive status were not found.
Taking into account behaviour test outcomes in Rottweiler pedigree certification was associated with a reduced prevalence of fear and aggression. The exclusion of fear/aggressive individuals from the breeding population on the basis of SAB-test outcomes may have had favourable effects on population genetics or incited preventive actions by breeders like not putting a dog forward for pedigree certification.
In our view, validated behaviour tests like the SAB-test can help to reduce unwanted behaviours in dog populations by breeding policies.