Abstract: As there is no statistical evidence that saddle fit influences the load exerted on a horse's back this study was performed to assess the hypothesis that the width of the tree significantly alters the pressure distribution on the back beneath the saddle. Nineteen sound horses were ridden at walk and trot on a treadmill with three saddles differing only in tree width. Kinetic data were recorded by a sensor mat. A minimum of 14 motion cycles were used in each trial. The saddles were classified into four groups depending on fit. For each horse, the saddle with the lowest overall force (LOF) was determined. Saddles were classified as “too-narrow” if they were one size (2 cm) narrower than the LOF saddle, and “too-wide” if they were one size (2 cm) wider than the LOF saddle. Saddles two sizes wider than LOF saddles were classified as “very-wide”. In the group of narrow saddles, the pressure in the caudal third (walk 0.63 N/cm2 +/- 0.10; trot 1.08 N/cm2 +/- 0.26) was significantly higher compared to the LOF saddles (walk 0.50 N/cm2 +/- 0.09; trot 0.86 N/cm2 +/- 0.28). In the middle transversal third, the pressure of the wide saddles (walk 0.73 N/cm2 +/- 0.06; trot 1.52 N/cm2 +/- 0.19) and very-wide saddles (walk 0.77 N/cm2 +/- 0.06; trot 1.57 N/cm2 +/- 0.19) was significantly higher compared to LOF saddles (walk 0.65 N/cm2 +/- 0.10/ 0.63 N/cm2 +/- 0.11; trot 1.33 N/cm2 +/- 0.22/1.27 N/cm2 +/- 0.20). This study demonstrates that the load under poorly fitting saddles is distributed over a smaller area than under properly fitting saddles, leading to potentially harmful pressures peaks.

Abstract: The purpose of this study is to find convincing arguments, how horses should be ridden correctly, especially concerning the best head and neck position. Currently in the riding world, the opinions differ: The traditional way is to ride a horse with its nose in front of the vertical, while a new method claims that pulling the nose behind the vertical with an extreme flexion of the poll implies “gymnastic movements”. This article is focussed on the welfare and comfort of the horse in different head-neck positions, expressed by behaviours which document discomfort. As a first step, the behaviour of standing horses was observed while their heads and necks were put into seven postulated or frequently assumed positions. In the hyperflexed position the horses displayed most discomfort (with 49,7% of all reactions, like open mouths, head tossing, tail movements and other signs of resentment). The second strongest reactions of discomfort were shown in the highly raised position of the head (34,9%). The moderately rounded neck position as in traditional dressage lessons was not without signs of discomfort either, but less than the other two positions (11,2%). The high position and the extended position did not cause discomfort at all (0,17% and 0,23% respectively). In a second step, horses moving in all gaits under a rider were observed at competitions without the riders´ knowledge. The total number of observations was divided into two categories (each containing 30 horses) on the basis of the common rules of the FN: ridden with the horse’s nose in front of the vertical and ridden with the horse’s nose behind the vertical. The proportion of horses showing discomfort with the nose behind the vertical was clearly much higher (89,3%) compared to those ridden with the nose in front of the vertical (10,7%). Thus, the horses in the first category displayed signs of discomfort 8 times more frequent than those in the second group. In addition, scans carried out at tournaments showed that 92.8% of the horses were ridden with the nose behind the vertical. A clear result of this study is that the reality of riding differs widely from the rules. These results also show that riding in the hyperflexed position causes a great deal of discomfort for the horses and therefore should be abolished.
Die aktuellen Diskussionen in der Reiterwelt, welche Art und Weise des Reitens, besonders welche Kopf-Hals-Stellung zu erstreben ist, werfen die Frage auf, ob und wie die Pferde selbst ihr Befinden zum Ausdruck bringen. Über die Empfindungen der Pferde in verschiedenen Kopfhaltungen ist bisher sehr wenig bekannt. Deswegen wurde zunächst an stehenden Pferden das Ausdrucksverhalten beobachtet. Missfallensäußerungen häuften sich (mit 49,7% aller gezeigten Verhaltensauffälligkeiten wie Sperren, Rückwärtsgehen und Kopfschlagen) in der aufgerollten, hyperflektierten Stellung des Halses. An zweiter Stelle folgten Unmutsäußerungen in der absolut aufgerichteten Haltung (34,9%). Auch die beigezäumte Haltung wurde nicht ohne Unmutsbekundungen hingenommen, hier war deren Anzahl aber wesentlich geringer (11,2%). Die hohe Kopfstellung (0,17%) und die Dehnungshaltung (0,23%) bereiteten den Tieren kaum Unbehagen. Auch das Ausdrucksverhalten der Pferde unter dem Reiter wurde untersucht. Hierfür wurden, unter Berücksichtigung der schriftlich fixierten Regeln für das Turnierwesen der FN, je 30 Pferde in zwei Kategorien beobachtet: mit der Stirnlinie vor der Senkrechten und Pferde mit der Stirnlinie hinter der Senkrechten. Die Beobachtungen wurden unbemerkt von den Reitern auf den Abreiteplätzen von Turnieren durchgeführt. Die Anzahl an Verhaltensauffälligkeiten der Pferde mit der Stirnlinie hinter der Senkrechten war deutlich (89,3 %) erhöht im Gegensatz zu der anderen Gruppe (10,7 %). Die Pferde mit der Stirnlinie hinter der Senkrechten zeigten 8 Mal mehr Unmutsäußerungen als die mit der Stirnlinie vor der Senkrechten. Entgegen den Regeln der FN zeigten die durchgeführten Scans, dass unmittelbar vor den Prüfungen auf Turnieren 92,8% der Pferde mit der Stirnnasen-Linie hinter der Senkrechten geritten wurden. Ein Befund dieser Studie ist die Feststellung, dass die Praxis deutlich von den Regeln abweicht. Das Reiten mit der Stirnlinie hinter der Senkrechten ist nach diesen Befunden abzulehnen, da die Pferde deutliches Unwohlsein in dieser Haltung signalisieren.

Abstract: Right hemisphere advantage in individual recognition (as shown by differences between response to strangers and companions) is clear in the domestic chick. Chicks using the left eye (and so, thanks to the complete optic decussation, predominantly the right hemisphere) discriminate between stranger and companion. Chicks using the right eye discriminate less clearly or not at all. The ability of left eyed chicks to respond to differences between strangers and companions stimuli is associated with a more general ability to detect and respond to novelty: this difference between left and right eyed chicks also holds for stimuli which are not social partners. The right hemisphere also shows advantage in tasks with a spatial component (topographical learning; response to change in the spatial context of a stimulus) in the chick, as in humans. Similar specialisations of the two hemispheres are also revealed in tests which involve olfactory cues presented by social partners. The special properties of the left hemisphere are less well established in the chick. Evidence reviewed here suggests that it tends to respond to selected properties of a stimulus and to use them to assign it to a category; such assignment then allows an appropriate response. When exposed to an imprinting stimulus (visual or auditory) a chick begins by using right eye or ear (suggesting left hemisphere control), and then shifts to the left eye or ear (suggesting right hemisphere control), as exposure continues. The left hemisphere here is thus involved whilst behaviour is dominated by vigorous response to releasing stimuli presented by an object. Subsequent learning about the full detailed properties of the stimulus, which is crucial for individual recognition, may explain the shift to right hemisphere control after prolonged exposure to the social stimulus. There is a marked sex difference in choice tests: females tend to choose companions in tests where males choose strangers. It is possible that this difference is specifically caused by stronger motivation to sustain social contact in female chicks, for which there is extensive evidence. However, sex differences in response to change in familiar stimuli are also marked in tests which do not involve social partners. Finally, in both sexes there are two periods during development in which there age-dependent shifts in bias to use one or other hemisphere. These periods (days 3-5 and 8-11) coincide with two major changes in the social behaviour of chicks reared by a hen in a normal brood. It is argued that one function of these periods is to bring fully into play the hemisphere most appropriate to the type of response to, and learning about, social partners which is needed at particular points in development. Parallels are discussed between the involvement of lateralised processes in the recognition of social partners in chicks and humans.

Abstract: This study examined the ability of two adult white rhinoceroses (Ceratotherium simum simum) to develop a visual discrimination between an open circle and a triangle. These stimuli were presented as black symbols on large white cards. The cards were presented 4.6 m apart and a food reward was given if the subject approached the open circle. Ten discrimination choices were given daily until each subject reached the criterion of 80% correct responding over a block of 50 trials. The female reached the criterion over trials 151–200, while the male required considerably longer (trials 501–550). The male's discrimination was dramatically affected by a shift in the food reward. This study demonstrates that these rhinos were able to develop a successful discrimination and this protocol could be used to further examine their visual acuity.

Abstract: The most abundant intestinal immunoglobulin and first line of specific immunological defense against environmental antigens is secretory immunoglobulin A. To better understand the effect of repeated stress on the secretion of intestinal IgA, the effects of restraint stress on IgA concentration and mRNA expression of the gene for the alpha-chain of IgA was assessed in both the duodenum and ileum of the rats. Restraint stress induced an increase in intestinal IgA, which was blocked by an adrenalectomy, suggesting a role of catecholamines and glucocorticoids. Whereas the blocking of glucocorticoid receptors by RU-486 did not affect the increased IgA concentration, it did reduce IgA alpha-chain mRNA expression in both segments, indicating a possible mediation on the part of glucocorticoids in IgA secretion by individual cells. Treatment with corticosterone significantly increased both the IgA concentration and IgA alpha-chain mRNA expression in ileum but not in duodenum, suggesting that glucocorticoids may act directly on IgA-antibody forming cells to increase IgA secretion in the former segment. A probable role by catecholamines was evidenced by the reduction in IgA concentration and IgA alpha-chain mRNA expression in both segments after a chemical sympathectomy with 6-hydroxydopamine (6-OHDA). Additionally, norepinephrine significantly reduced IgA alpha-chain mRNA levels but increased pIgR mRNA expression and IgA concentration in both intestinal segments. We propose that the increased intestinal IgA levels caused by repeated restraint stress is likely due to the effects of catecholamines on the transport of plgA across the epithelium.