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Author Davies, H.M.S.
Title The timing and distribution of strains around the surface of the midshaft of the third metacarpal bone during treadmill exercise in one Thoroughbred racehorse Type Journal Article
Year 2005 Publication Australian Veterinary Journal Abbreviated Journal Aust Vet J
Volume 83 Issue 3 Pages 157-162
Keywords Animals; Exercise Test/veterinary; Female; Gait/*physiology; Horses/*physiology; Metacarpus/*physiology; Motor Activity/physiology; Physical Conditioning, Animal/*physiology; Stress, Mechanical; Weight-Bearing/physiology
Abstract OBJECTIVE: To confirm that the midshaft dorsal cortex of the third metacarpal bone experienced higher compressive strains during fast exercise than the medial or lateral cortices, and that the strain peak occurred earlier in the hoof-down phase of the stride on the dorsal cortex than the medial or lateral cortices. DESIGN: Observations of a single horse. PROCEDURE: Strains were collected from a single, sound, 3-year-old Thoroughbred mare during treadmill exercise from rosette strain gauges implanted onto the medial, lateral and dorsal surfaces of the midshaft of the right cannon bone, simultaneously with data from a hoof switch that showed when the hoof was in the stance phase. RESULTS: Peak compressive strains on the dorsal surface of the third metacarpal bone were proportional to exercise speed and occurred at about 30% of stance. Peak compressive strains on the medial surface of the non-lead limb reached a maximum at a speed around 10 m/s and occurred at mid-stance. Peak compressive strains on the lateral surface varied in timing and size between strides at all exercise speeds, but remained less than -2000 microstrains. CONCLUSIONS: The timing of peak compressive strains on the dorsal cortex suggests a relationship to deceleration of the limb following hoof impact, so the main determinants of their size would be exercise speed and turning (as shown in previous experiments). This experiment confirms data from other laboratories that were published but not discussed, that peak compressive strains on the medial surface occur at mid-stance. This suggests that they are related to the support of body weight. The strains on the lateral cortex occurred at variable times so may be associated with the maintenance of balance as well as the support of body weight. Understanding the loading of the third metacarpal bone will help to determine causes of damage to it and ways in which the bone might be conditioned to prevent such damage.
Address Department of Veterinary Science, University of Melbourne, Parkville, Victoria 3010. h.davies@unimelb.edu.au
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ISSN 0005-0423 ISBN Medium
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Notes PMID:15825628 Approved no
Call Number Serial (up) 1891
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Author Macfadden, B.J.
Title Evolution. Fossil horses--evidence for evolution Type Journal Article
Year 2005 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume 307 Issue 5716 Pages 1728-1730
Keywords Animals; Body Size; DNA, Mitochondrial; Diet; *Equidae/anatomy & histology/classification/genetics; *Evolution; Feeding Behavior; *Fossils; *Horses/anatomy & histology/classification/genetics; Paleodontology; Phylogeny; Time; Tooth/anatomy & histology
Abstract
Address Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA. bmacfadd@flmnh.ufl.edu
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Series Editor Series Title Abbreviated Series Title
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ISSN 1095-9203 ISBN Medium
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Notes PMID:15774746 Approved no
Call Number Serial (up) 1892
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Author Bobbert, M.F.; Santamaria, S.
Title Contribution of the forelimbs and hindlimbs of the horse to mechanical energy changes in jumping Type Journal Article
Year 2005 Publication The Journal of Experimental Biology Abbreviated Journal J Exp Biol
Volume 208 Issue 2 Pages 249-260
Keywords Animals; Biomechanics; Forelimb/*physiology; Hindlimb/*physiology; Horses/*physiology; Locomotion/*physiology; Muscle, Skeletal/*physiology; Time Factors
Abstract The purpose of the present study was to gain more insight into the contribution of the forelimbs and hindlimbs of the horse to energy changes during the push-off for a jump. For this purpose, we collected kinematic data at 240 Hz from 23 5-year-old Warmbloods (average mass: 595 kg) performing free jumps over a 1.15 m high fence. From these data, we calculated the changes in mechanical energy and the changes in limb length and joint angles. The force carried by the forelimbs and the amount of energy stored was estimated from the distance between elbow and hoof, assuming that this part of the leg behaved as a linear spring. During the forelimb push, the total energy first decreased by 3.2 J kg(-1) and then increased again by 4.2 J kg(-1) to the end of the forelimb push. At the end of the forelimb push, the kinetic energy due to horizontal velocity of the centre of mass was 1.6 J kg(-1) less than at the start, while the effective energy (energy contributing to jump height) was 2.3 J kg(-1) greater. It was investigated to what extent these changes could involve passive spring-like behaviour of the forelimbs. The amount of energy stored and re-utilized in the distal tendons during the forelimb push was estimated to be on average 0.4 J kg(-1) in the trailing forelimb and 0.23 J kg(-1) in the leading forelimb. This means that a considerable amount of energy was first dissipated and subsequently regenerated by muscles, with triceps brachii probably being the most important contributor. During the hindlimb push, the muscles of the leg were primarily producing energy. The total increase in energy was 2.5 J kg(-1) and the peak power output amounted to 71 W kg(-1).
Address Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, van der Boechorstraat 9, NL-1081 BT Amsterdam, The Netherlands. MFBobbert@fbw.vu.nl
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ISSN 0022-0949 ISBN Medium
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Notes PMID:15634844 Approved no
Call Number Serial (up) 1895
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Author Spier, S.J.
Title P. McGreevy, Equine Behavior: A Guide for Veterinarians and Equine Scientists, Edinburgh, Saunders (2004) ISBN 0702026344 369 pp. (soft) [pound sign]45 Type Journal Article
Year 2005 Publication The Veterinary Journal Abbreviated Journal
Volume 169 Issue 3 Pages 375-222
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Call Number refbase @ user @ Serial (up) 1982
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Author Robert, N.; Walzer, C.; Ruegg, S.R.; Kaczensky, P.; Ganbaatar, O.; Stauffer, C.
Title Pathologic findings in reintroduced Przewalski's horses (Equus caballus przewalskii) in southwestern Mongolia Type Journal Article
Year 2005 Publication Journal of zoo and Wildlife Medicine : Official Publication of the American Association of Zoo Veterinarians Abbreviated Journal J Zoo Wildl Med
Volume 36 Issue 2 Pages 273-285
Keywords Animals; Babesiosis/epidemiology/pathology/*veterinary; Cause of Death; Conservation of Natural Resources; Disease Susceptibility/veterinary; Environment; Female; Food Chain; Horse Diseases/*epidemiology/pathology; Horses; Male; Mongolia/epidemiology; Streptococcal Infections/epidemiology/pathology/*veterinary; *Streptococcus equi; Theileriasis/*epidemiology/pathology; Weather
Abstract The Przewalski's horse (Equus caballus przewalskii) was extinct in the wild by the mid 1960s. The species has survived because of captive breeding only. The Takhin Tal reintroduction project is run by the International Takhi Group; it is one of two projects reintroducing horses to the wild in Mongolia. In 1997 the first harem group was released. The first foals were successfully raised in the wild in 1999. Currently, 63 Przewalski's horses live in Takhin Tal. Little information exists on causes of mortality before the implementation of a disease-monitoring program in 1998. Since 1999, all dead horses recovered (n = 28) have been examined and samples collected and submitted for further investigation. Equine piroplasmosis, a tick-transmitted disease caused by Babesia caballi or Theileria equi, is endemic in Takhin Tal and was identified as the cause of death of four stallions and one stillborn foal. In December 2000, wolf predation was implicated in the loss of several Przewalski's horses. However, thorough clinical, pathologic, and bacteriologic investigations performed on dead and surviving horses of this group revealed lesions compatible with strangles. The extreme Mongolian winter of 2000-2001 is thought to have most probably weakened the horses, making them more susceptible to opportunistic infection and subsequent wolf predation. Other occasional causes of death since 1999 were trauma, exhaustion, wasting, urolithiasis, pneumonia, abortion, and stillbirth. The pathologic examination of the Przewalski's horses did not result in a definitive diagnosis in each case. Several disease factors were found to be important in the initial phase of the reintroduction, which could potentially jeopardize the establishment of a self-sustaining population.
Address Center for Fish and Wildlife Health, Institute of Animal Pathology, University of Berne, Langgass-Strasse 122, CH-3001 Berne, Switzerland
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ISSN 1042-7260 ISBN Medium
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Notes PMID:17323569 Approved no
Call Number Serial (up) 2023
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Author Dumont, B.; Boissy, A.; Achard, C.; Sibbald, A.M.; Erhard, H.W.
Title Consistency of animal order in spontaneous group movements allows the measurement of leadership in a group of grazing heifers Type Journal Article
Year 2005 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.
Volume 95 Issue 1-2 Pages 55-66
Keywords Cattle; Grazing; Leadership; Movement order; Walking
Abstract The term `leadership' has been used in several different senses, resulting in very different ways of identifying leaders and apparently inconsistent conclusions on how leadership is determined in herbivores. We therefore propose the following definitions: (i) a leader is the individual that is consistently the one who initiates long-distance, spontaneous group movements toward a new feeding site and (ii) long-distance spontaneous group movements are movements which happen when an animal changes activity and location and is immediately followed by a similar change in activity and location by other members of the group. Using these definitions, we tested for consistency of movement order across time and situation within a group of fifteen 2-year-old heifers. We found that the same individual was recorded as the very first animal in 48% of movements toward a new feeding site and could therefore be identified as the `leader'. We also showed that movement order when the animals entered an experimental plot, or progressed slowly through the field during a grazing bout, did not produce the same result. This method, which enables us to identify leaders in groups of animals at pasture, should improve our knowledge of how leadership is determined in grazing herbivores.
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Call Number Equine Behaviour @ team @ room B 3.029 Serial (up) 2027
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Author Barrett, L.; Henzi, P.
Title The social nature of primate cognition Type Journal Article
Year 2005 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 272 Issue 1575 Pages 1865-1875
Keywords Animals; Brain/anatomy & histology/*physiology; Cognition/*physiology; *Evolution; Intelligence/*physiology; Primates/*physiology; *Social Behavior
Abstract The hypothesis that the enlarged brain size of the primates was selected for by social, rather than purely ecological, factors has been strongly influential in studies of primate cognition and behaviour over the past two decades. However, the Machiavellian intelligence hypothesis, also known as the social brain hypothesis, tends to emphasize certain traits and behaviours, like exploitation and deception, at the expense of others, such as tolerance and behavioural coordination, and therefore presents only one view of how social life may shape cognition. This review outlines work from other relevant disciplines, including evolutionary economics, cognitive science and neurophysiology, to illustrate how these can be used to build a more general theoretical framework, incorporating notions of embodied and distributed cognition, in which to situate questions concerning the evolution of primate social cognition.
Address School of Biological Sciences, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK. louiseb@liv.ac.uk
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ISSN 0962-8452 ISBN Medium
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Notes PMID:16191591 Approved no
Call Number Serial (up) 2086
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Author Dunbar, R.I.M.; McAdam, M.R.; O'connell, S.
Title Mental rehearsal in great apes (Pan troglodytes and Pongo pygmaeus) and children Type Journal Article
Year 2005 Publication Behavioural Processes Abbreviated Journal Behav. Process.
Volume 69 Issue 3 Pages 323-330
Keywords Algorithms; Animals; Child; Child, Preschool; Food; Frontal Lobe/anatomy & histology/physiology; Humans; *Imagination; Pan troglodytes; Pongo pygmaeus; Problem Solving/*physiology; Psychomotor Performance/physiology; Reward
Abstract The ability to rehearse possible future courses of action in the mind is an important feature of advanced social cognition in humans, and the “social brain” hypothesis implies that it might also be a feature of primate social cognition. We tested two chimpanzees, six orangutans and 63 children aged 3-7 years on a set of four puzzle boxes, half of which were presented with an opportunity to observe the box before being allowed to open it (“prior view”), the others being given without an opportunity to examine the boxes before handling them (“no prior view”). When learning effects are partialled out, puzzle boxes in the “prior view” condition were opened significantly faster than boxes given in the “no prior view” condition by the children, but not by either of the great apes. The three species differ significantly in the speed with which they opened boxes in the “no prior view” condition. The three species' performance on this task was a function of relative frontal lobe volume, suggesting that it may be possible to identify quantitative neuropsychological differences between species.
Address Evolutionary Psychology Research Group, School of Biological Sciences, University of Liverpool, Biosciences Building, Crown Street, Liverpool L69 7ZB, UK. rimd@liv.ac.uk
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ISSN 0376-6357 ISBN Medium
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Notes PMID:15896530 Approved no
Call Number Serial (up) 2097
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Author Pompilio, L.; Kacelnik, A.
Title State-dependent learning and suboptimal choice: when starlings prefer long over short delays to food Type Journal Article
Year 2005 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 70 Issue 3 Pages 571-578
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Abstract Recent studies have used labels such as `work ethics', `sunk costs' and `state-dependent preferences' for apparent anomalies in animals' choices. They suggest that preference between options relates to the options' history, rather than depending exclusively on the expected payoffs. For instance, European starlings, Sturnus vulgaris, trained to obtain identical food rewards from two sources while in two levels of hunger preferred the food source previously associated with higher hunger, regardless of the birds' state at the time of testing. We extended this experimentally and theoretically by studying starlings choosing between sources that differed not only in history but also in the objective properties (delay until reward) of the payoffs they delivered. Two options (PF and H) were initially presented in single-option sessions when subjects were, respectively, prefed or hungry. While option PF offered a delay until reward of 10 s in all treatments, option H delivered delays of 10, 12.5, 15 and 17.5 s in four treatments. When training was completed, we tested preference between the options. When delays in both options were equal (10 s), the birds strongly preferred H. When delay in H was 17.5 s, the birds were indifferent, with intermediate results for intermediate treatments. Preference was not mediated by disrupted knowledge of the delays. Thus, preferences were driven by past state-dependent gains, rather than by the joint effect of the birds' state at the time of choice and knowledge of the absolute properties of each alternative, as assumed in state-dependent, path-independent models of optimal choice.
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Call Number Serial (up) 2104
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Author Fernández-Juricic,E.; Smith, R.; Kacelnik,A.
Title Increasing the costs of conspecific scanning in socially foraging starlings affects vigilance and foraging behaviour Type Journal Article
Year 2005 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.
Volume 69 Issue 1 Pages 73-81
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Abstract Social foragers receive and use information both about companions (social information) and about events external to the group, such as presence of potential predators. Scanning behaviour is often incorporated in theoretical models using simplifying assumptions in relation to the trade-off in information gathering between body postures (head-up versus head-down); however, some avian visual systems may allow individuals to scan in both body postures. We studied these issues experimentally, using starlings, Sturnus vulgaris, foraging in enclosures on natural fields. We varied the availability of information from conspecifics by placing visual barriers that blocked the view when the subjects were in head-down position and by manipulating the distance between group members. We found that as social information was reduced, starlings spent more time scanning (on and off the ground) and head-up scanning was mainly oriented towards conspecifics. The visual-obstruction effects imply that some information about conspecifics is normally gathered while starlings are foraging head-down. Neighbour distance and visual obstruction negatively affected food-searching rates and intake rates in two ways: (1) the effect of obstruction was mediated mostly through time competition between foraging and scanning on the ground, and (2) the effect of distance was due to a reduction in the rate of prey returns per searching effort while the birds were head-down. We conclude that the head-up posture is only one component of scanning, that the effects of head-down scanning should also be considered in species with ample visual fields, and that scanning in starlings is strongly connected to monitoring other flock members.
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Notes Approved no
Call Number Serial (up) 2105
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