Genetic evaluation of behaviour in dogs

Abstract

A dog's behavioural characteristics are important for the dog, for the dog owner and for society as a whole. Behavioural traits can be changed by breeding, but to be effective when selecting breeding animals, good methods for measuring behaviour are essential. The aim of this thesis was to provide information on a number of dog behavioural measurement methods regarding their potential to be used for genetic evaluation: the Herding Trait Characterisation, the Swedish and Norwegian English Setter field trials, the Swedish Armed Forces temperament test, the Dog Mentality Assessment (DMA), and an extended version of the Canine Behavioral Assessment and Research Questionnaire. The aim was also to advance our understanding of factors affecting the usefulness of behavioural measurements for breeding purposes. Average heritabilities for behavioural variables (items) within measurement method ranged from 0.1 to 0.3, and the items were markedly influenced by systematic environ-mental effects. All studied measurement methods can be used for selection of breeding animals, but selection based on individual performance is suboptimal. Using BLUP breeding values would substantially increase accuracy of selection and the potential genetic progress and is therefore recommended. Rough Collie results from DMA showed strong genetic correlations with important everyday life traits as described by dog owners in the questionnaire. Therefore, in order to improve everyday life behaviour in Rough Collie, DMA breeding values for relevant traits should be used for selection. The results indicated that from a heritability perspective, behavioural measurements should be objective rather than subjective, and neutral rather than passing value judgments. Collaboration between countries within breed is also advised because a joint genetic evaluation increases the number of selection candidates, and may also increase breeding value accuracies rather dramatically, as was shown for the English Setter field trial results from Sweden and Norway. For half of the studied methods, the measured items were summarized into composite traits. Heritability estimates for composite traits were higher than the average of the items used for creating these traits. Because the composite traits also can be expected to be more stable over time and between situations, it would be advisable to use them as selection traits.