Quantifying aspects of young horses' temperament: consistency of behavioural variables

Performance of horses, whether in sports or in leisure, depends on both phy sical abilities as well as temperament. The aim of the present work was to measure individual variation and consistency of behavioural variables, rela ted to temperament, in young horses of the same breed and age, and reared u nder controlled housing conditions and management. A total of 41 Dutch Warm blood horses were tested at 9, 10, 21 and 22 months of age in two behaviour al tests, i.e. the novel object test and the handling test. In the novel ob ject test horses were confronted with an open umbrella that was lowered fro m the ceiling. In the handling test horses were led by a human to cross a b ridge. Per test, behavioural variables in the following behavioural classes were observed: locomotor activity, latency times, postural expressions and vocalisations. Within years, all behavioural variables in the handling test, and all but t wo in the novel object test were positively correlated (0.36 < R-S < 0.81, P < 0.05). For both tests, at 9, 10, 21 and 22 months of age, a principal c omponent analysis (PCA) was carried out to examine whether there were indic ations for underlying components of these individual behavioural variables that could possibly serve as measures for temperamental traits. The first c omponent in the novel object test could be regarded as 'flightiness' and th e second as 'sensitiveness'. In the handling test, the first component was suggested to relate to 'patience', the second component to 'willingness to perform'. The temperamental trait 'flightiness' (novel object test) as well as the temperamental trait 'patience' (handling test) were positively corr elated within both years (0.36 < R-S < 0.65, P < 0.05). For the traits 'sen sitiveness' (novel object test) and 'willingness to perform' (handling test ) a positive correlation was only found within the first year (0.44 < R-S < 0.57, P < 0.01). A few individual behavioural variables showed consistency over years. Additionally, just one out of four temperamental traits, namel y 'flightiness', proved to be consistent over years (R-S = 0.49, P < 0.01). The temperamental trait 'patience' showed a trend between years (R-S = 0.3 1, 0.05 < P < 0.1). It is concluded that the behavioural tests employed in the present study ca n be used to reliably identify individual behavioural variables and tempera mental traits in young horses. Long-term consistency, i.e. between subseque nt years, could not be demonstrated convincingly. Nevertheless, future work may indicate that employing the same approach and considering an even long er time period or different phases of the horse's life, long-term consisten cy does exist. (C) 2001 Elsevier Science B.V. All rights reserved.