The use of a behaviour test for selection of dogs for service and breeding. II. Heritability for tested parameters and effect of selection based on service dog characteristics

Heritability calculated for characteristics evaluated in behavioural tests can be used as a tool to select different kinds of service dogs. The evaluation was based on the test results of 13 10 German shepherds and 797 Labrador retrievers. The heritability for all evaluated characteristics of the two breeds was significantly different from zero with the exception of the characteristic prey drive in Labrador retrievers. The test results for each characteristic were summarised to form an index value which simplified the interpretation of the test results. The heritability for this index value was 0.24 for both German shepherds and Labrador retrievers, a value that must be considered high as it included all tested parameters. The heritability was also calculated for the four factors derived from a factor analysis of the test results. Heritability estimates for these four factors were 0.15 to 0.32. The results show that complex behavioural patterns in dogs can be subjectively evaluated by an experienced person and that no more than a few characteristics are needed in order to describe the differences between dogs. Breeding results in a German shepherd population at the Swedish Dog Training Centre (SDTC) improved a relatively short time after the initiation of basing the selection of breeding animals on the index value of each individual animal. German shepherds bred by the SDTC also had higher index values than privately bred dogs which shows the importance of a goal-oriented breeding programme with emphasis on service dog characteristics. ’ Corresponding author. Apt #3, 41 Hawthorn St., Cambridge, MA 02138, USA. 0168.1591/97/$17.00