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Argue, C. K., & Clayton, H. M. (1993). A preliminary study of transitions between the walk and trot in dressage horses. Acta Anat (Basel), 146(2-3), 179–182.
Abstract: The object of this study was to determine the limb support sequence during the transitions from walk to trot and from trot to walk in dressage horses under saddle and to test the null hypothesis that the limb support sequence during the transitions is not related to the level of training. Sixteen dressage horses training at novice to FEI Grand Prix level were videotaped performing an average of 9 transitions each from walk to trot and from trot to walk. The 30-Hz videotapes were viewed in slow motion, and based on the limb support sequence the transitions were categorized into two types. In type 1 transitions there were no intermediate steps between the walk and trot sequences. Type 2 transitions were characterized by intermediate steps, including a single support phase. The Kendall rank-order correlation coefficient showed that a higher level of training was positively associated with an increased percentage of type 1 transitions for both walk-to-trot transitions (p < or = 0.05) and trot-to-walk transitions (p < or = 0.01). No significant preference for initiating or completing the trot on the left or right diagonal was found using the binomial test for individual horses and the Wilcoxon signed-ranks test for the group.
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Aviad, A. D., & Houpt, J. B. (1994). The molecular weight of therapeutic hyaluronan (sodium hyaluronate): how significant is it? J Rheumatol, 21(2), 297–301.
Abstract: Various molecular weight hyaluronic acid (HA) preparations have been injected into joints for the treatment of human and equine osteoarthritis. A therapeutic advantage has been claimed for commercial products with a molecular weight in the range found in normal synovial fluid (SF), compared to lower molecular weight products. But a correlation between molecular weight and efficacy is not borne out by an analysis of the available literature on clinical results. SF viscosity, HA concentration, HA molecular weight and rate of synthesis in joint disease. It is proposed that the beneficial effect of injected HA in joint disease may be due to pharmacological rather than to physical properties.
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McComb, K., & Clutton-Brock, T. (1994). Is mate choice copying or aggregation responsible for skewed distributions of females on leks? Proc Biol Sci, 255(1342), 13–19.
Abstract: In several lek-breeding populations of birds and mammals, females arriving on leks tend to join males that already have females in their territories. This might occur either because females have an evolved preference for mating with males that are attractive to other females, or because they join groups of other females to obtain greater safety from predation or dangerous harassment by males. We have previously used controlled experiments to show that oestrous fallow deer females join males with established harems because they are attracted to female groups rather than to the males themselves. Here we demonstrate that the preference for males with females over males without females is specific to oestrous females and weak or absent in anoestrous ones, and that it is not associated with a preference for mating with males that have previously been seen to mate with other females. Furthermore, oestrous females given the choice between males that do not already have females with them show no significant preference for antlered over deantlered males or for older males over younger ones. We conclude that female attraction to other females on the lek is likely to be an adaptation to avoiding harassment in mixed-sex herds. In this situation, a male's ability to maintain the cohesion of his harem may be the principal cause of variation in mating success between males.
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Zeeb, K. (1994). [Possibilities for the all-year free-range raising of horses]. Dtsch Tierarztl Wochenschr, 101(3), 122–123.
Abstract: The ethological concept concerning supply of needs an avoidance of damage is mentioned as a possibility for the evaluation of welfare aspects related to animal management. The 250 Dulmen horses kept on 300 ha by the Duke of Croy show what must be provided for horse-keeping in a semi-natural environment: Sufficient food and water, efficient shelter as well as adequate structures for the needs of horses concerning social and comfort behaviour. A catalogue of factors, functions and facilities for this kind of horse-keeping is presented.
Keywords: Animal Feed; *Animal Husbandry; Animal Welfare; Animals; Germany; Horses/*physiology; Housing, Animal; Seasons; Weather
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Andrews, F. M., Ralston, S. L., Sommardahl, C. S., Maykuth, P. L., Green, E. M., White, S. L., et al. (1994). Weight, water, and cation losses in horses competing in a three-day event. J Am Vet Med Assoc, 205(5), 721–724.
Abstract: Body weight of 48 horses competing in a 3-day event was measured the day before the event (baseline), following the dressage phase of the event (day 1), after the endurance phases of the event (day 2), and 18 to 24 hours after the endurance phases (day 3). Plasma sodium and potassium concentrations were measured the evening before, immediately after, and 10 minutes after the endurance phases. Total body water, water loss, and net exchangeable cation loss were then calculated. Body weight and total body water were significantly decreased, compared with baseline values, at all times during the event, and significant water loss was detected. The largest changes were recorded after the endurance phases of the event. Water deficits were still detected 18 to 24 hours after the endurance phases of the event. Mean plasma sodium concentration was significantly increased immediately after the endurance phases of the event, compared with concentration measured the evening before, and remained increased after the 10-minute recovery period, presumably because of dehydration. Mean plasma potassium concentration was significantly increased immediately after the endurance phases of the event, compared with concentration measured the evening before, but was not increased after the 10-minute recovery period.
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Clayton, H. M. (1994). Comparison of the stride kinematics of the collected, working, medium and extended trot in horses. Equine Vet J, 26(3), 230–234.
Abstract: Highly-trained dressage horses were studied to test the hypothesis that stride length is altered independently of stride duration in the transitions between the collected, working, medium and extended trot. Six well-trained dressage horses were filmed at a frame rate of 150 frames/s performing the collected, working, medium and extended trots in a sand arena. Temporal, linear and angular data were extracted from the films, with 4 strides being analysed for each horse and gait type. There were no significant asymmetries between the left and rights limbs or diagonals when data from the whole group were pooled, but 3 horses showed asymmetries in one or more variables (P < 0.01). Analysis of variance and post-hoc tests indicated that the speed increased significantly (P < 0.01) from the collected (3.20 m/s) to the working (3.61 m/s) to the medium (4.47 m/s) to the extended (4.93 m/s) trot. The increases in speed were associated with a significant increase in stride length from 250 cm in the collected trot, to 273 cm in the working trot, 326 cm in the medium trot and 355 cm in the extended trot (P < 0.01). The lengthening of the stride was a result of increases between each gait type in the over-reach distance, whereas the diagonal distance was significantly longer in the extended than the collected trot only (P < 0.01). The stride duration tended to decrease as speed increased, and the difference became significant between the collected and extended trots (P < 0.01).
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Atock, M. A., & Williams, R. B. (1994). Welfare of competition horses. Rev Sci Tech, 13(1), 217–232.
Abstract: In the large majority of cases and circumstances, horses benefit from their association with man. However, abuse of horses can occur, due to neglect or through the pressures of competition. The welfare of all animals, including competition horses, has become increasingly topical over the past ten years. Equestrian sport is coming under closer public scrutiny due to reports of apparent abuse. The bodies responsible for regulating these sports strenuously endeavour to protect the welfare of horses which compete under their rules and regulations. The Federation Equestre Internationale (FEI: International Equestrian Federation) is the sole authority for all international events in dressage, show-jumping, three-day event, driving, endurance riding and vaulting. The FEI rules illustrate the ways in which the welfare of competing horses is safeguarded.
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Houpt, K. A. (1995). New perspectives on equine stereotypic behaviour (Vol. 27).
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de Waal, F. B. (1995). Bonobo sex and society. Sci Am, 272(3), 82–88.
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Krebs, J. R., Clayton, N. S., Hampton, R. R., & Shettleworth, S. J. (1995). Effects of photoperiod on food-storing and the hippocampus in birds. Neuroreport, 6(12), 1701–1704.
Abstract: Birds that store food have a relatively large hippocampus compared to non-storing species. The hippocampus shows seasonal differences in neurogenesis and volume in black-capped chikadees (Parus atricapillus) taken from the wild at different times of year. We compared hippocampal volumes in black-capped chickadees captured at the same time but differing in food-storing behaviour because of manipulations of photoperiod in the laboratory. Differences in food-storing behaviour were not accompanied by differences in the volume of the hippocampus. Hippocampal volumes also did not differ between two groups of a non-food-storing control species, house sparrows (Passer domesticus), exposed to the same conditions as the chickadees.
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