Abstract: There is evidence that more than 47% of the sports horse population in normal work may be lame, but the lameness is not recognized by owners or trainers. An alternative means of detecting pain may be recognition of behavioral changes in ridden horses. It has been demonstrated that there are differences in facial expressions in nonlame and lame horses. The purpose of this study was to develop a whole horse ethogram for ridden horses and to determine whether it could be applied repeatedly by 1 observer (repeatability study, 9 horses) and if, by application of a related pain behavior score, lame horses (n = 24) and nonlame horses (n = 13) could be differentiated. It was hypothesized that there would be some overlap in pain behavior scores among nonlame and lame horses; and that overall, nonlame horses would have a lower pain behavior score than lame horses. The ethogram was developed with 117 behavioral markers, and the horses were graded twice in random order by a trained specialist using video footage. Overall, there was a good correlation between the 2 assessments (P < 0.001; R2 = 0.91). Behavioral markers that were not consistent across the 2 assessments were omitted, reducing the ethogram to 70 markers. The modified ethogram was applied to video recordings of the nonlame horses and lame horses (ethogram evaluation). There was a strong correlation between 20 behavioral markers and the presence of lameness. The ethogram was subsequently simplified to 24 behavioral markers, by the amalgamation of similar behaviors which scored similarly and by omission of markers which showed unreliable results in relation to lameness. Following this, the maximum individual occurrence score for lame horses was 14 (out of 24 possible markers), with a median and mean score of 9 (±2 standard deviation) compared with a maximum score of 6 for nonlame horses, with a median and mean score of 2 (±1.4). For lame horses, the following behaviors occurred significantly more (P < 0.05, chi-square): ears back, mouth opening, tongue out, change in eye posture and expression, going above the bit, head tossing, tilting the head, unwillingness to go, crookedness, hurrying, changing gait spontaneously, poor quality canter, resisting, and stumbling and toe dragging. Recognition of these features as potential indicators of musculoskeletal pain may enable earlier recognition of lameness and avoidance of punishment-based training. Further research is necessary to verify this new ethogram for assessment of pain in ridden horses.

Abstract: Most horses are trained by negative reinforcement. Currently, however, no standardised test for evaluating horses' negative reinforcement learning ability is available. The aim of this study was to develop an objective test to investigate negative reinforcement learning in horses. Twenty-four Icelandic horses (3 years old) were included in this study. The horses were tested in a pressure-release task on three separate days with 10, 7 and 5 trials on each side, respectively. Each trial consisted of pressure being applied on the hindquarter with an algometer. The force of the pressure was increased until the horse moved laterally away from the point of pressure. There was a significant decrease in required force over trials on the first test day (P<0.001), but not the second and third day. The intercepts on days 2 and 3 differed significantly from day 1 (P<0.001), but not each other. Significantly stronger force was required on the right side compared to the left (P<0.001), but there was no difference between first and second side tested (P=0.56). Individual performance was evaluated by median-force and the change in force over trials on the first test day. These two measures may explain different characteristics of negative reinforcement learning. In conclusion, this study presents a novel, standardised test for evaluating negative reinforcement learning ability in horses.

Abstract: Animal management often involves procedures that, while unlikely to cause physical pain, still cause aversive responses. The domestic horse (Equus caballus) regularly has excessive hair clipped off to facilitate its use as a riding/driving animal and this procedure causes adverse behavioral responses in some animals. The aim of this study was to compare behavioral and physiological measures to assess the aversive effect of this procedure. Ten horses were selected on the basis of being either compliant (C: n=5) or non-compliant (NC: n=5) during this procedure. The horses were subjected to a sham clipping procedure (SC: where the blades had been removed from the clippers) for a period of ten minutes. Measures were taken pre, during and post SC (-10min to +30min) and mean values calculated for ALL horses and for C and NC separately. Behavioral activity was scored (scale 1-5) by twenty students from video footage in (phase/group-blind scoring). Heart rate (HR), salivary cortisol and eye temperature were monitored throughout the procedure. The NC horses were found to be significantly more behaviorally active/less relaxed throughout the trial than C horses (p<0.05) with the greatest difference occurring during the SC procedure (p<0.01). NC horses were more active/less relaxed during, compared with pre or post SC (p<0.05), but showed no behavioral difference pre and post SC. HR of the NC horses was higher than that of the C horses throughout the trial but only significantly so after 10min of SC (p<0.01). ALL horses showed a significant increase in HR between +5 and +10min into the procedure (p<0.05). There was a significant increase in salivary cortisol concentration in ALL horses post procedure (p<0.01) with levels peaking at 20minute post SC. No significant differences in salivary cortisol concentration between C and NC were found at any stage of the trial. Eye temperature increased significantly in ALL horses during SC, peaking at +10min into the procedure (p<0.05) and then decreased substantially when SC had ceased (p<0.01). Although no significant differences were found between C and NC per se, there was a significant interaction between group and phase of trial (p<0.05) with the NC group showing a greater decrease in eye temperature post SC. There was a significant positive correlation between changes in salivary cortisol concentration and eye temperature (p<0.01) but no correlation between any of the other measures. Although the behavioral response of C and NC to this procedure was significantly different the physiological responses indicated that ALL horses found the procedure aversive. Eye temperature could be used as an objective and immediate measure of how an animal is responding to a specific situation in order to evaluate management procedures and adapt them where appropriate to reduce the negative impact on animal health and welfare.

Abstract: An Gitterstäben, die in der Pferdehaltung an verschiedenen Stellen verwendet werden, können sich Pferde verletzen, wenn sie ihre Köpfe oder ihre Hufe hindurchstecken und nicht zurückziehen können. Um das Verletzungsrisiko zu reduzieren sind lichte Weiten und Materialstärken von Gitterstäben so zu wählen, dass Pferdeköpfe und -hufe entweder nicht zwischen den Freiräumen hindurchpassen oder aber gefahrlos wieder zurückgezogen werden können. Die bisherige Forschung liefert jedoch keine belastbaren Aussagen zu Stababständen (senkrecht und waagerecht), die für Pferde ungefährlich sind. Die in der Praxis verwendeten und in der Literatur empfohlenen Gitterstababstände beruhen auf Erfahrungswerten und technischen Materialeigenschaften. In der vorliegenden Untersuchung wurden Pferdeköpfe und -hufe von insgesamt 480 Pferden (233 Stuten, 204 Wallache und 43 Hengste) von 23 verschiedenen Rassen vermessen, um auf Grundlage der Anatomie der Pferde Aussagen über die Eignung von marktüblichen Stababständen in der Praxis treffen zu können. Es stellte sich heraus, dass bei senkrechten Gitterstäben eine lichte Weite von nicht mehr als 5 cm für alle Pferde ab einem Stockmaß von 110 cm und einem Alter von zwei Jahren als sicher bezeichnet werden kann. Bei waagerechten Gitterstäben erwies sich eine lichte Weite von genau 17 cm als sicher. Dies gilt für alle Pferde ab einem Alter von zwei Jahren oder ab einem Stockmaß von 148 cm.
Kritisch sind die lichten Weiten von Panels zu beurteilen. Hier zeigte sich, dass die handelsüblichen Abstände der Gitterstäbe für die meisten Pferde eine erhebliche Gefahr darstellen. Wenn die Pferde beispielsweise versuchen außerhalb der Panels zu fressen und dabei ihren Kopf durch die Gitterstäbe stecken, kann es leicht passieren, dass sie sich mit dem Kopf zwischen den Gitterstäben verklemmen.
[At bars, used in various places in horse husbandry, horses can hurt themselves when retracting their heads or hooves after pushing them through the interspaces. In order to reduce the risk of injury, the clear widths and material thicknesses of bars should be chosen so that horse heads and hooves either cannot pass between the spaces or can be retracted safely. However, research to date has not provided any reliable information on bar width (vertical and horizontal) that is safe for horses. Grid bar width used in practice and recommended in the literature is based on empirical values and technical material properties. In this study, heads and hooves of 480 horses (233 mares, 204 geldings and 43 stallions) of 23 breeds were measured for making statements about the suitability of standard bar width, when considering the anatomy of the horse. It turned out that for vertical bars, an interspace of no more than five centimetres can be considered to be safe for all horses of a height of 110 centimetres and an age of two years and more. With horizontal lattice bars, a clear width of exactly 17 centimetres proved to be safe. This applies to all horses of a height of 148 centimetres and an age of two years or more. The clear widths of panels must be considered critical for horse welfare. When horses, for example, try to eat outside the panels and put their head through the bars, they may get stuck.]