|
|
Marr, I., Preisler, V., Farmer, K., Stefanski, V., & Krueger, K. (2020). Non-invasive stress evaluation in domestic horses (Equus caballus): impact of housing conditions on sensory laterality and immunoglobulin A. Royal Society Open Science, 7(2), 191994.
Abstract: The study aimed to evaluate sensory laterality and concentration of faecal immunoglobulin A (IgA) as non-invasive measures of stress in horses by comparing them with the already established measures of motor laterality and faecal glucocorticoid metabolites (FGMs). Eleven three-year-old horses were exposed to known stressful situations (change of housing, initial training) to assess the two new parameters. Sensory laterality initially shifted significantly to the left and faecal FGMs were significantly increased on the change from group to individual housing and remained high through initial training. Motor laterality shifted significantly to the left after one week of individual stabling. Faecal IgA remained unchanged throughout the experiment. We therefore suggest that sensory laterality may be helpful in assessing acute stress in horses, especially on an individual level, as it proved to be an objective behavioural parameter that is easy to observe. Comparably, motor laterality may be helpful in assessing long-lasting stress. The results indicate that stress changes sensory laterality in horses, but further research is needed on a larger sample to evaluate elevated chronic stress, as it was not clear whether the horses of the present study experienced compromised welfare, which it has been proposed may affect faecal IgA.
|
|
|
|
Krueger, K. (2010). “Erfasst” das Pferd die menschliche Psyche". In M. Dettling, C. Opgen-Rhein, & M. Kläschen (Eds.), Pferdegestützte Therapie bei psychischen Erkrankungen (pp. 40–51). Stuttgart: Schattauer Verlag.
|
|
|
|
Marr, I., Stefanski, V., & Krueger, K. (2022). Lateralität – ein Indikator für das Tierwohl?[Laterality – an animal welfare indicator?]. Der Praktische Tierarzt, 103(12/2022), 1246–12757.
Abstract: Ein gutes Tierwohl definiert sich nicht nur durch die Abwesenheit von Stressindikatoren, sondern auch durch das Vorhandensein von Indikatoren, die auf ein gutes Wohlergehen hinweisen. So können stressbedingte Erkrankungen vermieden werden. Zur Bestimmung des Tierwohls bei Pferden wurde daher untersucht, inwieweit sich die sensorische Lateralität (einseitiger Gebrauch von Sinnesorganen) und die motorische Lateralität (einseitiger Gebrauch von Gliedmaßen) als einfach, schnell und kostengünstig zu erhebende Parameter eignen. Hierzu werden neben aktueller Literatur auch die eigenen Untersuchungsergebnisse zusammenfassend dargestellt. Die nach außen sichtbar werdende sensorische und motorische Lateralität sind das Resultat der cerebralen Lateralisierung. Dies beinhaltet nicht nur die Aufgabenteilung beider Gehirnhälften für ein effizienteres Aufnehmen und Speichern von Informationen, sondern sie steht auch in Verbindung mit der Entstehung und Verarbeitung von Emotionen, die maßgeblich am Wohlergehen eines Lebewesens beteiligt sind. Kurzzeitige Stressoren führen zu einer Erregung, die je nach Erfahrungen mit positiven oder negativen Emotionen in Verbindung steht. Emotionen helfen dem Organismus dabei, zu überleben. Andauernde negative Emotionen durch regelmäßige oder anhaltende negative Ereignisse führen zu Stress und reduzieren die Erwartung positiver Ereignisse (negativer cognitive Bias). Das Tier ist im Wohlergehen beeinträchtigt. Jüngst zeigte insbesondere die Messung der motorischen Lateralität Potenzial als Indikator für lang anhaltenden und chronischen Stress, denn gestresste Pferde, deren Stresshormonlevel stark ansteigt, zeigen einen zunehmenden Gebrauch der linken Gliedmaßen über einen längeren Zeitraum. Weiterhin zeigen erste Messungen einen Zusammenhang zwischen einer linksseitigen motorischen Lateralität und einer reduzierten Erwartung positiver Ereignisse (negativer cognitive Bias). Zusammen mit der sensorischen Lateralität, die in einer akuten Stressphase ebenso eine Linksverschiebung zeigt und somit als Indikator für Kurzzeitstress gilt, kann eine generelle, vermehrte Linksseitigkeit auch einen Hinweis auf erhöhte Emotionalität und Stressanfälligkeit sein. Eine sich steigernde Linksseitigkeit bedeutet eine präferierte Informationsverarbeitung durch die rechte Gehirnhälfte, die beispielsweise reaktives Verhalten, starke Emotionen und Stressantworten steuert. Es stellte sich jedoch heraus, dass wie bei allen Stressindikatoren auch in der Lateralitätsmessung ein Vergleichswert aus einer vorangegangenen Messung notwendig ist, denn nur Veränderungen zum häufiger werdenden Gebrauch der linken Seite können auf Stress bei Pferden hindeuten und die parallele Erhebung weiterer Parameter, wie zum Beispiel das Verhalten oder Stresshormone, können die Aussage der Lateralität bekräftigen.
|
|
|
|
Krueger, K., Flauger, B., Farmer, K., & Maros, K. (2011). Horses (Equus caballus) use human local enhancement cues and adjust to human attention. Anim. Cogn., 14(2), 187–201.
Abstract: This study evaluates the horse (Equus caballus) use of human local enhancement cues and reaction to human attention when making feeding decisions. The superior performance of dogs in observing human states of attention suggests this ability evolved with domestication. However, some species show an improved ability to read human cues through socialization and training. We observed 60 horses approach a bucket with feed in a three-way object-choice task when confronted with (a) an unfamiliar or (b) a familiar person in 4 different situations: (1) squatting behind the bucket, facing the horse (2) standing behind the bucket, facing the horse (3) standing behind the bucket in a back-turned position, gazing away from the horse and (4) standing a few meters from the bucket in a distant, back-turned position, again gazing away from the horse. Additionally, postures 1 and 2 were tested both with the person looking permanently at the horse and with the person alternating their gaze between the horse and the bucket. When the person remained behind the correct bucket, it was chosen significantly above chance. However, when the test person was turned and distant from the buckets, the horses’ performance deteriorated. In the turned person situations, the horses approached a familiar person and walked towards their focus of attention significantly more often than with an unfamiliar person. Additionally, in the squatting and standing person situations, some horses approached the person before approaching the correct bucket. This happened more with a familiar person. We therefore conclude that horses can use humans as a local enhancement cue independently of their body posture or gaze consistency when the persons remain close to the food source and that horses seem to orientate on the attention of familiar more than of unfamiliar persons. We suggest that socialization and training improve the ability of horses to read human cues.
|
|
|
|
Krueger, K., & Flauger, B. (2011). Olfactory recognition of individual competitors by means of faeces in horse (Equus caballus). Anim. Cogn., 14(2), 245–257.
Abstract: Living in complex social systems requires perceptual and cognitive capacities for the recognition of group membership and individual competitors. Olfaction is one means by which this can be achieved. Many animals can identify individual proteins in urine, skin secretions, or saliva by scent. Additionally, marking behaviour in several mammals and especially in horses indicates the importance of sniffing conspecifics’ faeces for olfactory recognition. To test this hypothesis, we conducted two separate experiments: Experiment 1 addressed the question of whether horses can recognise the group membership of other horses by sniffing their faeces. The horses were presented with four faecal samples: (1) their own, (2) those of other members of their own group, (3) those of unfamiliar mares, and (4) those of unfamiliar geldings. Experiment two was designed to assess whether horses can identify the group member from whom a faecal sample came. Here, we presented two groups of horses with faecal samples from their group mates in random distribution. As controls, soil heaps and sheep faecal samples were used. In experiment one, horses distinguished their own from their conspecifics’ faeces, but did not differentiate between familiarity and sex. In experiment two, the horses from both groups paid most attention to the faeces of the horses from which they received the highest amount of aggressive behaviours. We therefore suggest that horses of both sexes can distinguish individual competitors among their group mates by the smell of their faeces.
|
|
|
|
Krueger, K., Farmer, K., & Heinze, J. (2014). The effects of age, rank and neophobia on social learning in horses. Anim. Cogn., 17(3), 645–655.
Abstract: Social learning is said to meet the demands of complex environments in which individuals compete over resources and co-operate to share resources. Horses (Equus caballus) were thought to lack social learning skills because they feed on homogenously distributed resources with few reasons for conflict. However, the horse’s social environment is complex, which raises the possibility that its capacity for social transfer of feeding behaviour has been underestimated. We conducted a social learning experiment using 30 socially kept horses of different ages. Five horses, one from each group, were chosen as demonstrators, and the remaining 25 horses were designated observers. Observers from each group were allowed to watch their group demonstrator opening a feeding apparatus. We found that young, low ranking, and more exploratory horses learned by observing older members of their own group, and the older the horse, the more slowly it appeared to learn. Social learning may be an adaptive specialisation to the social environment. Older animals may avoid the potential costs of acquiring complex and potentially disadvantageous feeding behaviours from younger group members. We argue that horses show social learning in the context of their social ecology, and that research procedures must take such contexts into account. Misconceptions about the horse’s sociality may have hampered earlier studies.
|
|
|
|
Krueger, K. (2017). Perissodactyla Cognition. In J. Vonk, & T. Shackelford (Eds.), Encyclopedia of Animal Cognition and Behavior (pp. 1–10). Cham: Springer International Publishing.
|
|
|
|
Krueger, K., Marr, I., & Farmer, K. (2017). Equine Cognition. In J. Vonk, & T. Shackelford (Eds.), Encyclopedia of Animal Cognition and Behavior (pp. 1–11). Cham: Springer International Publishing.
|
|
|
|
Krueger, K. (2008). Social Ecology of Horses. In j. Korb and J. Heinze (Ed.), Ecology of Social Evolution (pp. 195–206). Heidelberg: Springer Verlag.
Abstract: Horses (Equidae ) are believed to clearly demonstrate the links between ecology and social organization. Their social cognitive abilities enable them to succeed in many different environments, including those provided for them by humans, or the ones domestic horses encounter when escaping from their human care takers. Living in groups takes different shapes in equids. Their aggregation and group cohesion can be explained by Hamilton“s selfish herd theory. However, when an individual joins and to which group it joins appears to be an active individual decision depending on predation pressure, intra group harassment and resource availability. The latest research concerning the social knowledge horses display in eavesdropping experiments affirms the need for an extension of simple herd concepts in horses for a cognitive component. Horses obviously realize the social composition of their group and determine their own position in it. The horses exceedingly flexible social behavior demands for explanations about the cognitive mechanisms, which allow them to make individual decisions. ”Ecology conditions like those that favour the evolution of open behavioural programs sometimes also favour the evolution of the beginnings of consciousness, by favouring conscious choice. Or in other words, consciousness originates with the choice that are left open by open behavioural programs." Popper (1977)
|
|
|
|
Krueger, K. (2014). “Pferdehaltung und Ethologie der Pferde” im Bachelorstudiengang Pferdewirtschaft. In : S. Lepp und C. Niederdrenk-Felgner (Ed.), Forschendes Lernen initiieren, umsetzen und reflektieren (pp. 54–81). Bielefeld: UniversitätsVerlag Webler.
|
|
