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Flauger, B., Krueger, K., Gerhards, H., & Möstl, E. (2010). Simplified method to measure glucocorticoid metabolites in faeces of horses. Vet Res Comm, 34(2), 185–195.
Abstract: Glucocorticoids or their metabolites can be measured in several body fluids or excreta, including plasma, saliva, urine and faeces. In recent years the measurement of glucocorticoid metabolites (GCMs) in faeces has gained increasing attention, because of its suitability for wild populations. In horses, however, the group-specific enzyme immunoassay described so far has a limited racticability due to its complex extraction procedure. Therefore, we tested the applicability of
other enzyme immunoassays for glucocorticoid metabolites. The present study clearly proved that an enzyme immunoassay (EIA) for 11-oxoetiocholanolone using 11-oxoetiocholanolone-17-CMO: BSA (3α,11-oxo-A EIA) as antigen showed high amounts of immunoreactive substances. Therefore it was possible to use just a small amount of the supernatant of a methanolic suspension of faeces. The results
correlated well with the already described method for measuring GCMs in horse faeces, i.e. analysing the samples with an EIA after a two step clean up procedure of the samples (Merl et al. 2000). In addition, the 3α,11-oxo-A EIA has the advantage of providing a bigger difference between baseline values and peak values after ACTH stimulation. The new assay increased the accuracy of the test,
lowered the expenses per sample, and storing samples at room temperature after collection was less critical than with other assays investigated in our study. This is a big advantage both in the field of wildlife management of equids and in the field of equestrian sports and it shows the importance of choosing an assay which is in good accordance with the metabolites excreted in a given species.
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Krueger, K., & Flauger, B. (2009). Social and individual olfaction through horse faeces (Equus caballus). In P. M. Kappeler, & M. Schwibbe (Eds.), Program of the 4. Thementagung der Ethologischen Gesellschaft, Februar 12 -14, 2009. (23). Göttingen: Dpz.
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Krueger, K., & Flauger, B. (2009). Horses (Equus caballus) show respect and trust in their owners. In P. M. Kappeler, & M. Schwibbe (Eds.), Program of the 4. Thementagung der Ethologischen Gesellschaft, Februar 12 -14, 2009. (32). Göttingen: Dpz.
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Flauger, B., & Krueger, K. (2012). Social feeding decisions in horses (Equus caballus). In Proceedings of the 2. International Equine Science Meeting (Vol. in press). Wald: Xenophon Publishing.
Abstract: Like many other herbivores equids feed on rather evenly distributed resources. Especially in ruminants several studies have proved the influence of social organisations, rank, sex and the depletion of feeding sites on the feeding behaviour of individuals. However, it is not yet understood whether social aspects affect horses´ feeding decisions. Horses roam on vast habitats with constantly changing vegetation. In non-competitive situations domestic horses tend to return to the same feeding site until it is overgrazed. Whereas, for competition over limited food the social status of the individuals appears to be important. Curiosity about the influence of social rank and different social feeding conditions on the horses´ feeding decisions between two buckets, equally filled with high-quality surplus food, led us to create the test situation described here. The observer horses were alternately tested with a dominant and a subordinate demonstrator placed in one of three different positions. We conclude that domestic horses use cognitive strategic decision making in order to decide where to feed in a social feeding situation. When possible they tend to return to the same, continuously supplied feeding site and switch to an “avoidance tendency” when another horse is already feeding from it or in the presence of a dominant horse. Thus the position and the social rank of conspecifics affect the feeding strategy of horses.
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Flauger, B., Krueger, K., Gerhards, H., & Moestl, E. (2009). Measurement of glucocorticoid metabolites in horse faeces: the validation of different group specific enzymeimmunoassays and extraction methods. In S. Cremer, A. Schrempf, & J. Heinze (Eds.), Proceeding of the 102. Annual meeting of the Deutsche Zoologische Gesellschaft (DZG). (166). München: Dt. Zoologische Ges.
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Flauger, B., & Krueger, K. (2013). Aggressionslevel und Platzangebot bei Pferden (Equus caballus) [ Aggression level and enclosure size in horses (Equus caballus)]. Pferdeheilkunde, 29(4), 495–504.
Abstract: Viele Pferdebesitzer bevorzugen aus Angst vor aggressiven Interaktionen und Verletzungsgefahr der Tiere untereinander die Einzelhaltung, obwohl von Tierschutzorganisationen die Gruppenhaltung für Pferde empfohlen wird. In dieser Studie beobachteten wir während des alltäglichen Soziallebens als auch bei der Eingliederung von neuen Gruppenmitgliedern das Sozialverhalten, insbesondere das Aggressionsverhalten, von elf Gruppen domestizierter Pferde (Equus caballus) verschiedener Größe und Zusammensetzung. Während des alltäglichen Soziallebens hatten die Gruppe und der Paddock-Typ (Gras / kein Gras) keinen Einfluss auf die Verhaltensweisen, wohingegen die Paddockgröße unter 10000 m2 einen signifikanten Einfluss auf die submissiven Verhaltensweisen (GzLM; n=56; t=-2.061, P=0.044) und einen nicht signifikanten Einfluss auf die aggressiven Verhaltensweisen (GzLM; n=56; t=-1.782, P=0.081) hatte. Allerdings verringerten sich sowohl die aggressiven als auch die submissiven Verhaltensweisen mit steigendem Platzangebot bis zu 10000 m2 (Spearman rank Korrelation; n=56; aggressive Verhaltensweisen: r = -0.313, P = 0.019; submissive Verhaltensweisen: r = -0.328, P = 0.014). Während den Eingliederungen reduzierten sich die Aggressionen pro Stunde mit der Vergrößerung des Platzangebotes (Spearman rank Korrelation; n=28; r=-0.402, P=0.034). Dies zeigte sich noch deutlicher, wenn Beobachtungen mit einem Platzangebot von über 10000 m2 ausgeschlos- sen wurden (Spearman rank Korrelation; n=23; r=-0.549, P=0.007). Während des alltäglichen Soziallebens näherte sich der Aggressionslevel der Nulllinie an, wenn das Platzangebot pro Pferd mehr als 331 m2 betrug. Deshalb empfehlen wir zur Reduzierung des Aggressionslevels und des Verletzungsrisikos von sozial gehaltenen Pferdegruppen ein Platzangebot von mindestens 331 m2 pro Pferd.
[Even though animal welfare organisations propose group housing for horse welfare, many owners stable horses individually for fear of aggressive interactions and injury risks. In the present study we observed social behaviour, and especially aggressiveness, in eleven domestic horse groups (Equus caballus) of different size and composition, in basic social situations and when new group members were introduced. During basic social situations, the group and the type of paddock (grass / no grass) had no effect on any of the behaviours, where- as the enclosure size below 10,000 m2 had a significant effect on submissive behaviour (GzLM; n=56; t=-2.061, P=0.044) and an insignificant effect on aggressive behaviour (GzLM; n=56; t=-1.782, P=0.081). However, aggressive and submissive behaviour dimi- nished with the increase of enclosure sizes up to 10,000 m2 (Spearman rank correlation; n = 56; aggressive behaviour: r = -0.313, P=0.019; submissive behaviour: r=-0.328, P=0.014). During introductions, aggression levels per hour decreased with any increase of enclosure size (Spearman rank correlation; n=28; r=-0.402, P=0.034) and even more when enclosure sizes above 10,000 m2 were excluded (Spearman rank correlation; n=23; r=-0.549, P=0.007). During basic social situations the aggression level approached zero when the space allowance was more than 331 m2 per horse. We therefore recommend keeping horse groups in an enclosure with at least 331 m2 per horse to reduce aggression and injuries.]
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Flauger, B., & Krueger, K. (2008). Ecology and evolution of equine cognitive abilities. In IESM 2008.
Abstract: The cognitive abilities of social ungulates, in particular horses, have widely been neglected. Preliminary results suggest that horses are capable of social cognition which they acquire through social learning. They gain information from the observation of the interaction of a conspecific and a human experimenter, and adjust their own behaviour towards the experimenter with respect to the observed horse"s reaction and relative dominance status (Krueger and Heinze, 2007). Horses are a highly social species that still exists in different evolutionary stages: domestic horses, feral horses and wild horses (Przewalski horses). Additionally, domestic and wild horses differ in their individual social behaviour. For example, in social interactions Przewalski horses appear to act significantly more aggressively than domestic horses. Therefore studies on horses are particularly suitable to investigate whether convergent social evolution favours convergent cognitive evolution. By a comparative study concerning their reasoning abilities in a specific situation, we will attempt to determine the influence of domestication and feralisation on the evolution of social cognition and to investigate possible differences in their abilities to cope with stressful situations. We started to observe the behaviour of domestic and wild horses, in particular during the integration into new social groups, especially in relation with their knowledge of the social structure of new groups and their own relative social status. Selected agonistic interactions will be measured and statistically evaluated. Additionally, the stress level of the horses will be determined by an analysis of stress hormone levels, particularly cortisol metabolites, in plasma, saliva and faeces.
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Krueger, K., & Flauger, B. (2007). Social learning in horses from a novel perspective. Behav. Process., 76(1), 37–39.
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Krueger, K., Schneider, G., Flauger, B., & Heinze, J. (2015). Context-dependent third-party intervention in agonistic encounters of male Przewalski horses. Behav. Process., 121, 54–62.
Abstract: Abstract One mechanism to resolve conflict among group members is third party intervention, for which several functions, such as kin protection, alliance formation, and the promotion of group cohesion have been proposed. Still, empirical research on the function of intervention behaviour is rare. We studied 40 cases of intervention behaviour in a field study on 13 semi-wild bachelor horses (Equus ferus przewalskii) in (a) standard social situations, and (b) when new horses joined the group (i.e. introductions). Only interventions in agonistic encounters were analysed. Eight of 13 animals directed intervention behaviour toward threatening animal in agonistic encounters of group members. One stallion was particularly active. The stallions did not intervene to support former group mates or kin and interventions were not reciprocated. In introduction situations and in standard social situations, the interveners supported animals which were lower in rank, but targeted, threatening animals of comparable social rank. After introductions, stallions received more affiliative behaviour from animals they supported and thus appeared to intervene for alliance formation. In standard social situations, interveners did not receive more affiliative behaviour from animals they supported and may primarily have intervened to promote group cohesion and to reduce social disruption within the group.
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Krueger, K., & Flauger, B. (2008). Social feeding decisions in horses (Equus caballus). Behav. Process., 78(1), 76–83.
Abstract: Like many other herbivores, in a natural environment equids feed on rather evenly distributed resources. However, the vegetation in their vast habitats constantly changes. If food is plentiful only little competition occurs over food, and in non-competitive situations domestic horses tend to return to the same feeding site until it is overgrazed. In contrast, they compete over limited food for which the social status of the individuals appears to be important. Especially in ruminants several studies have proved an influence of social organisations, rank, sex and the depletion of feeding sites on the feeding behaviour of individuals. However, it is not yet understood whether and how social aspects affect horses“ feeding decisions. Curiosity about the influence of social rank on the horses” feeding decisions between two, equally with high-quality surplus food-filled buckets placed in different social feeding conditions, led us to create the test below. The observer horses were alternately tested with a dominant and a subordinate demonstrator placed in one of the three different positions. We conclude that domestic horses use social cognition and strategic decision making in order to decide where to feed in a social feeding situation. When possible they tend to return to the same, continuously supplied feeding site and switch to an “avoidance tendency” in the presence of dominant horses or when another horse is already feeding there. Thus, the social rank and the position of conspecifics affect the feeding strategy of horses.
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