Behavioral responses and heart rates of stereotyping and non-stereotyping geldings to four stimuli
L.L. Meers, E. van Avermaet, C. Moons and F.O. Ödberg
Department of Ethology, University of Ghent, Merelbeke, Belgium
The short-term causality of stable vices has received much less attention than that of long-term factors. To what extent do frequently occurring stimuli in daily management influence the frequency of stereotypy? Are there differences between crib-biting and weaving?
Methods
Fifteen geldings, aged between 5 and 17 years, were stabled in individual boxes
and had visual contact with neighbouring horses. Ten behaviors were observed
using a Psion LZ64 configured with The
Observer 3.0, and heart rates were measured using the Polar Horse Trainer SW
3.0. The five crib-biters and the five weavers had all been heavily stereotyping
for at least three years. Five normal horses were included as controls.
Each horse was exposed once during four consecutive stimuli, using a Latin Square design with one extra period:
Each stimulus was presented during the first two minutes of a 10-min observation period. It was technically impossible to record behavior without the horse perceiving the observer. Data were analysed using a repeated measures ANOVA or Kruskal-Wallis test, depending on the results of a normality test and variance check. Newman-Keuls test was used as a post-hoc test. The main results Control horses remained significantly more immobile than both types of stereotypers after stimulus 2 (F = 11.089, p = 0.005). All three groups differed significantly after stimulus 1, weavers being more immobile than controls, and controls being more immobile than crib-biters (F = 22.659, p < 0.001). Crib-biters had significantly lower heart rates than weavers and control horses during stimulus 1 (H = 10.349, p = 0.006) and stimulus 3 (F = 41.794, p < 0.001). Controls had significantly lower heart rates than weavers after stimulus 3. Leading a horse away during the initial two minutes induced a strong increase in heart rate in controls and weavers, but not in crib-biters. These results suggest that weavers and crib-biters react differently, depending on the type of stimulus. They also confirm previous data concerning the de-arousing effect of crib-biting. Weaving does not seem to have the same effect - at least not on heart rate.
Crib-biting decreased significantly after stimulus 2 but increased after stimulus 4 (F = 30.296, p < 0.001). Stimulus 2 induced an increase in nibbling (mainly bedding), whereas stimulus 4 caused a decrease. Weaving was not significantly influenced by any stimulus. Weavers and crib-biters nibbled significantly less than controls after stimuli 1 (F = 21.659, p < 0.001), 3 (F = 4.769, p = 0.043) and 4 (F = 4.531, p = 0.048).
Paper presented at Measuring Behavior 2002 , 4th International Conference on Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, The Netherlands