|
|
Zebisch, A., May, A., Reese, S., & Gehlen, H. (2013). Effect of different head-neck positions on physical and psychological stress parameters in the ridden horse. J Anim Physiol Anim Nutr, 98(5), 901–907.
Abstract: Summary Different head?neck positions (HNPs) are used in equestrian sports and are regarded as desirable for training and competition by riders, judges and trainers. Even though some studies have been indicative of hyperflexion having negative effects on horses, this unnatural position is frequently used. In the present study, the influence of different HNPs on physical and psychological stress parameters in the ridden horse was investigated. Heart rate (HR), heart rate variability (HRV) and blood cortisol levels were measured in 18 horses. Low frequency (LF) and high frequency (HF) are power components in the frequency domain measurement of HRV which show the activity of the sympathetic and parasympathetic nervous system. Values were recorded at rest, while riding with a working HNP and while riding with hyperflexion of the horse's head, neck and poll. In addition, rideability and behaviour during the different investigation stages were evaluated by the rider and by an observer. Neither the HR nor the HRV showed a significant difference between working HNP (HR = 105 ± 22/min; LF/HF = 3.89 ± 5.68; LF = 37.28 ± 10.77%) and hyperflexion (HR = 110 ± 18; LF/HF = 1.94 ± 2.21; LF = 38.39 ± 13.01%). Blood cortisol levels revealed a significant increase comparing working HNP (158 ± 60 nm) and hyperflexion (176 ± 64 nm, p = 0.01). The evaluation of rider and observer resulted in clear changes of rideability and behavioural changes for the worse in all parameters collected between a working HNP and hyperflexion. In conclusion, changes of the cortisol blood level as a physical parameter led to the assumption that hyperflexion of head, neck and poll effects a stress reaction in the horse, and observation of the behaviour illustrates adverse effects on the well-being of horses during hyperflexion.
|
|
|
|
Krueger, K., & Lerbs, S. (2013). Die Schiefe, und die motorische sowie sensorische Lateralität des Pferdes. In Jahrestagung der DVG, Fachgruppe: Tierschutz & Ethologie und Tierhaltung Umwelt und Tierhygiene.
|
|
|
|
Herbst, C. T., Herzel, H., Svec, J. G., Wyman, M. T., & Fitch, W. T. (2013). Visualization of system dynamics using phasegrams. J R Soc Interface, 10.
|
|
|
|
GONÇALVES DA SILVA, A., CAMPOS-ARCEIZ, A., & ZAVADA, M. S. (2013). On tapir ecology, evolution and conservation: what we know and future perspectives–part II. Integrative Zoology, 8(1), 1–3.
|
|
|
|
Fuchs, K., Götz, K., Manschel, K., Pohl, L., Preisendanz, L., Weil, S., et al. (2013). Vergleich der Interaktionen von Pferden in Boxenhaltung mit Weidegang und Pferden in Offenstallhaltung. In Göttinger Pferdetage’13 (65).
|
|
|
|
Ruess, M., Schmelz, A., & Krueger, K. (2013). Einfluss vitomechanischer Schwingungen auf das Muskuloskeletalsystem der Pferde. In Göttinger Pferdetage’13 (111).
|
|
|
|
Lerbs, S., Raue, T., & Krueger, K. (2013). Untersuchung der natürlichen Schiefe der Fohlen in Abhängigkeit zur sensorischen und motorischen Lateralität, sowie zur Seitenpräferenz beim Saugen. In Göttinger Pferdetage’13.
|
|
|
|
Larsson, M. (2013). The optic chiasm: a turning point in the evolution of eye/hand coordination. Front. Zool., 10(1), 41.
Abstract: The primate visual system has a uniquely high proportion of ipsilateral retinal projections, retinal ganglial cells that do not cross the midline in the optic chiasm. The general assumption is that this developed due to the selective advantage of accurate depth perception through stereopsis. Here, the hypothesis that the need for accurate eye-forelimb coordination substantially influenced the evolution of the primate visual system is presented. Evolutionary processes may change the direction of retinal ganglial cells. Crossing, or non-crossing, in the optic chiasm determines which hemisphere receives visual feedback in reaching tasks. Each hemisphere receives little tactile and proprioceptive information about the ipsilateral hand. The eye-forelimb hypothesis proposes that abundant ipsilateral retinal projections developed in the primate brain to synthesize, in a single hemisphere, visual, tactile, proprioceptive, and motor information about a given hand, and that this improved eye-hand coordination and optimized the size of the brain. If accurate eye-hand coordination was a major factor in the evolution of stereopsis, stereopsis is likely to be highly developed for activity in the area where the hands most often operate.The primate visual system is ideally suited for tasks within arm's length and in the inferior visual field, where most manual activity takes place. Altering of ocular dominance in reaching tasks, reduced cross-modal cuing effects when arms are crossed, response of neurons in the primary motor cortex to viewed actions of a hand, multimodal neuron response to tactile as well as visual events, and extensive use of multimodal sensory information in reaching maneuvers support the premise that benefits of accurate limb control influenced the evolution of the primate visual system. The eye-forelimb hypothesis implies that evolutionary change toward hemidecussation in the optic chiasm provided parsimonious neural pathways in animals developing frontal vision and visually guided forelimbs, and also suggests a new perspective on vision convergence in prey and predatory animals.
|
|
|
|
Silk, J., Cheney, D., & Seyfarth, R. (2013). A practical guide to the study of social relationships. Evol. Anthropol., 22(5), 213–225.
Abstract: Behavioral ecologists have devoted considerable effort to identifying the sources of variation in individual reproductive success. Much of this work has focused on the characteristics of individuals, such as their sex and rank. However, many animals live in stable social groups and the fitness of individuals depends at least in part on the outcome of their interactions with other group members. For example, in many primate species, high dominance rank enhances access to resources and reproductive success. The ability to acquire and maintain high rank often depends on the availability and effectiveness of coalitionary support. Allies may be cultivated and coalitions may be reinforced by affiliative interactions such as grooming, food sharing, and tolerance. These findings suggest that if we want to understand the selective pressures that shape the social behavior of primates, it will be profitable to broaden our focus from the characteristics of individuals to the properties of the relationships that they form with others. The goal of this paper is to discuss a set of methods that can be used to quantify the properties of social relationships.
|
|
|
|
Iliopoulos, Y., Youlatos, D., & Sgardelis, S. (2013). Wolf pack rendezvous site selection in Greece is mainly affected by anthropogenic landscape features. Eur J Wildl Res, 60.
|
|
