Table 1.
Study population: horses’ breed, sex and age for each riding school.
Figure 1.
The withdrawn posture of “withdrawn” horses.
Pictures of a horse a) in a withdrawn posture, b) standing non-resting and c) resting. Withdrawn posture is characterized by a similar height between the horse’s neck and back (the nape – withers – back angle approximately 180°) and a stretched neck (obtuse jaw-neck angle). This posture is distinguished from postures associated with observation of the environment (for which the neck is higher), and resting, when eyes are at least partly closed and the horse’s neck is rounder [20], [21]. Note that the restricted size of the box (3 m * 3 m) prevented the authors from taking a picture of the whole horse displaying the withdrawn posture, as we chose to use the same lens in order to limit shape distortion between pictures.
Figure 2.
Test areas for tactile sensitivity assessment: withers, chest and groin.
Figure 3.
Behavioural characteristics of “withdrawn” bouts of “withdrawn” horses compared to horses standing non-resting observed under natural conditions.
(a) rates of ear position changes (number of ear position changes per number of withdrawn/standing non-resting bouts); (b) rates of head position changes (number of head position changes per number of withdrawn/standing non-resting bouts, and (c) gaze durations of withdrawn/standing non-resting bouts (s) for “withdrawn” horses and horses standing non-resting observed under natural conditions. Data are given as boxplot diagrams showing medians (lines in the boxes), 25 and 75% quartiles (boxes) and minimum and maximum ranges (whiskers). Unusual features of “withdrawn” horses are the absence of ear and head movements and a fixed gaze.
Figure 4.
Low responsiveness to environmental stimuli by “withdrawn” horses.
(a) Proportion of horses with high reactivity scores (i.e. ≥12; as 12 is the median score, thus including the 50% more reactive horses) for reactions to von Frey filaments applications, and (b) “C” scores (indifference, i.e. no change in activity) in the sudden human approach test. Data for (b) are given as boxplot diagrams showing medians (lines in the boxes), 25 and 75% quartiles (boxes) and minimum and maximum ranges (whiskers). Only half of the “withdrawn” horses had a high total reactivity score, whereas most of other horses (i.e. that never displayed the withdrawn posture) did. “Withdrawn” horses also displayed more often indifference to a sudden human approach than non- withdrawn off horses. Chi-square and Mann Whitney tests, ** p<0.01.
Figure 5.
Mean plasma cortisol concentrations after a day’s work for “withdrawn” horses and “non- withdrawn” horses.
Data are given as boxplot diagrams showing medians (lines in the boxes), 25 and 75% quartiles (boxes) and minimum and maximum ranges (whiskers). “Withdrawn” horses had lower cortisol concentrations than non- withdrawn horses (i.e. that never performed the withdrawn posture). Mann Whitney test, * p<0.05.