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Hanggi, E. B. (2001). Can Horses Recognize Pictures? Proceedings of the Third International Conference of Cognitive Science, , 52–56.
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Meershoek, L. S., Schamhardt, H. C., Roepstorff, L., & Johnston, C. (2001). Forelimb tendon loading during jump landings and the influence of fence height. Equine Vet J Suppl, (33), 6–10.
Abstract: Lameness in athletic horses is often caused by forelimb tendon injuries, especially in the interosseus tendon (TI) and superficial digital flexor tendon (SDF), but also in the accessory ligament (AL) of the deep digital flexor tendon (DDF). In an attempt to explain the aetiology of these injuries, the present study investigated the loading of the tendons during landing after a jump. In jumping horses, the highest forces can be expected in the trailing limb during landing. Therefore, landing kinematics and ground reaction forces of the trailing forelimb were measured from 6 horses jumping single fences with low to medium heights of 0.80, 1.00 and 1.20 m. The tendon forces were calculated using inverse dynamics and an in vitro model of the lower forelimb. Calculated peak forces in the TI, SDF and DDF + AL during landing were 15.8, 13.9 and 11.7 kN respectively. The relative loading of the tendons (landing forces compared with failure forces determined in a separate study) increased from DDF to TI to SDF and was very high in SDF. This explains the low injury incidence of the DDF and the high injury incidence of the SDF. Fence height substantially influenced SDF forces, whereas it hardly influenced TI forces and did not influence AL strain. Reduction of fence height might therefore limit the risks for SDF injuries, but not for TI and AL injuries.
Keywords: Animals; Biomechanics; Forelimb/injuries/physiology; Horses/injuries/*physiology; Lameness, Animal/etiology; Ligaments, Articular/*physiology; Locomotion/*physiology; Physical Conditioning, Animal; Tendon Injuries/complications/physiopathology/veterinary; Tendons/*physiology; Weight-Bearing/physiology
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Robert, C., Audigie, F., Valette, J. P., Pourcelot, P., & Denoix, J. M. (2001). Effects of treadmill speed on the mechanics of the back in the trotting saddlehorse. Equine Vet J Suppl, (33), 154–159.
Abstract: Speed related changes in trunk mechanics have not yet been investigated, although high-speed training is currently used in the horse. To evaluate the effects of speed on back kinematics and trunk muscles activity, 4 saddle horses were recorded while trotting on a horizontal treadmill at speeds ranging from 3.5 to 6 m/s. The 3-dimensional (3-D) trajectories of skin markers on the left side of the horse and the dorsal midline of the trunk were established. Electrical activity was simultaneously obtained from the longissimus dorsi (LD) and rectus abdominis (RA) muscles using surface electrodes. Ten consecutive strides were analysed for each horse at each of the 5 velocity steps. Electromyographic and kinematic data were time-standardised to the duration of the stride cycle and compared using an analysis of variance. The back extended during the first part of each diagonal stance phase when the RA was active and the back flexed during the second part of each diagonal stance phase when the LD was active. The onset and end of muscle activity came earlier in the stride cycle and muscle activity intensity increased when speed increased. The amplitude of vertical movement of the trunk and the maximal angles of flexion decreased with increasing speed, whereas the extension angles remained unchanged. This resulted in a decreased range of back flexion-extension. This study confirms that the primary role of trunk muscles is to control the stiffness of the back rather than to induce movements. Understanding the effects of speed on the back of healthy horses is a prerequisite for the prevention and treatment of back pathology.
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Watt, L. M., & McDonnell, S. M. (2001). Demonstration of Concept Formation in the Horse. Philadephia: University of Pennsylvania.
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Ferenc S. (2001). Computer-ssisted analysis of the developing brain motor system and coordinated locomotion in the foal. Ph.D. thesis, , .
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Wynne C. D. L. (2001). Animal Cognition: The Mental Lives of Animals. Palgrave.
Abstract: Covering a wide range of key topics, from reasoning and communication to sensation and complex problem-solving, this engagingly-written text presents a comprehensive survey of contemporary research on animal cognition. Written for anyone with an interest in animal cognition, but without a background in animal behaviour, it endeavours to explain what makes animals tick.
With numerous illustrations and including exciting recent studies from many little-studied species (such as the weakly electric African fish), this text is ideal for psychology students who are interested in how much of our human cognition is shared by other species, for students of biology who want to know how complex animal behaviour can get, and for all those with an interest in the animal mind. |
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Carroll, J., Murphy, C. J., Neitz, M., Hoeve, J. N., & Neitz, J. (2001). Photopigment basis for dichromatic color vision in the horse. J Vis, 1(2), 80–87.
Abstract: Horses, like other ungulates, are active in the day, at dusk, dawn, and night; and, they have eyes designed to have both high sensitivity for vision in dim light and good visual acuity under higher light levels (Walls, 1942). Typically, daytime activity is associated with the presence of multiple cone classes and color-vision capacity (Jacobs, 1993). Previous studies in other ungulates, such as pigs, goats, cows, sheep and deer, have shown that they have two spectrally different cone types, and hence, at least the photopigment basis for dichromatic color vision (Neitz & Jacobs, 1989; Jacobs, Deegan II, Neitz, Murphy, Miller, & Marchinton, 1994; Jacobs, Deegan II, & Neitz, 1998). Here, electroretinogram flicker photometry was used to measure the spectral sensitivities of the cones in the domestic horse (Equus caballus). Two distinct spectral mechanisms were identified and are consistent with the presence of a short-wavelength-sensitive (S) and a middle-to-long-wavelength-sensitive (M/L) cone. The spectral sensitivity of the S cone was estimated to have a peak of 428 nm, while the M/L cone had a peak of 539 nm. These two cone types would provide the basis for dichromatic color vision consistent with recent results from behavioral testing of horses (Macuda & Timney, 1999; Macuda & Timney, 2000; Timney & Macuda, 2001). The spectral peak of the M/L cone photopigment measured here, in vivo, is similar to that obtained when the gene was sequenced, cloned, and expressed in vitro (Yokoyama & Radlwimmer, 1999). Of the ungulates that have been studied to date, all have the photopigment basis for dichromatic color vision; however, they differ considerably from one another in the spectral tuning of their cone pigments. These differences may represent adaptations to the different visual requirements of different species.
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Budras, K. D., Scheibe, K., Patan, B., Streich, W. J., & Kim, K. (2001). Laminitis in Przewalski horses kept in a semireserve. J Vet Sci, 2(1), 1–7.
Abstract: Semireserves were created by the European Conservation Project for scientific research in preparation for reintroduction in the wilderness. They are defined as enclosures large enough to carry a group of Przewalski horses throughout the year without any additional feeding. The semireserve offers diverse opportunities for significant scientific research. As part of a general screening program, the hoof development in a group of Przewalski horses was investigated in the semireserve Schorfheide near Berlin. Since the foundation of this semireserve in 1992, veterinary treatment was not necessary with the exception of hoof trimming in two animals in 1993. However, major health problems were encountered in the spring of 1999, when three other mares showed signs of laminitis. The initial diagnosis by the authors and the local veterinary surgeon based on observation of behaviour, gait, stance, walk and trot of three mares whose initial weights were higher than those of the healthy mares. The initial diagnosis was confirmed by palpation and the occurrence of very deep horn rings on all hooves and a laminitic horn ring on the right front hoof of one mare. An adequate laminitic therapy was not possible under the conditions of a semireserve. The applied management aimed at two goals: 1. To reduce endotoxin production and acidosis in the horses by reducing the ingestion of carbohydrate rich food. 2. To reduce the mares level of activity and to prevent tearing of the suspensory apparatus of the coffin bone. To achieve these two goals it was decided to remove the three laminitic mares from the rich pasture in the main part of the semireserve and to confine them onto the poorer pasture of the small separately fenced area. All three affected mares had fully recovered from their laminitic condition. Prevention of grass laminitis can be achieved by the following measures: 1. Reduction in grass intake could be achieved by increasing the grazing pressure by an increase in stocking rate of the horses or mixed grazing with another species such as sheep. 2. A longer term solution to the problem may well be to sow specific varieties of grass with lower concentrations of water soluble carbohydrate.
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Itakura, S., Agnetta, B., Hare, B., & Tomasello, M. (2001). Chimpanzee Use of Human and Conspecific Social Cues to Locate Hidden Food. Dev Sci, 2(2), 448–456.
Abstract: Two studies are reported in which chimpanzees attempted to use social cues to locate hidden food in one of two possible hiding places. In the first study four chimpanzees were exposed to a local enhancement cue (the informant approached and looked to the location where food was hidden and then remained beside it) and a gaze/point cue (the informant gazed and manually pointed towards the location where the food was hidden). Each cue was given by both a human informant and a chimpanzee informant. In the second study 12 chimpanzees were exposed to a gaze direction cue in combination with a vocal cue (the human informant gazed to the hiding location and produced one of two different vocalizations – a 'food-bark' or a human word-form). The results were – (i) all subjects were quite skillful with the local enhancement cue, no matter who produced it; (ii) few subjects were skillful with the gaze/point cue, no matter who produced it (most of these being individuals who had been raised in infancy by humans); and (iii) most subjects were skillful when the human gazed and vocalized at the hiding place, with little difference between the two types of vocal cue. Findings are discussed in terms of chimpanzees' apparent need for additional cues, over and above gaze direction cues, to indicate the presence of food.
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Rizzolatti, G., Fogassi, L., & Gallese, V. (2001). Neurophysiological mechanisms underlying the understanding and imitation of action. Nat Rev Neurosci, 2(9), 661–670.
Abstract: What are the neural bases of action understanding? Although this capacity could merely involve visual analysis of the action, it has been argued that we actually map this visual information onto its motor representation in our nervous system. Here we discuss evidence for the existence of a system, the ‘mirror system’, that seems to serve this mapping function in primates and humans, and explore its implications for the understanding and imitation of action.
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