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Weishaupt, M. A. (2008). Adaptation strategies of horses with lameness. Vet Clin North Am Equine Pract, 24(1), 79–100.
Abstract: The skill to diagnose lameness in horses is paramount for every equine practitioner. Early recognition of locomotor deficiencies plays a central role in sports medicine management, preventing deterioration of the disease or catastrophic injuries. Horses use characteristic compensatory movements of specific body parts to decrease loading of the affected limb. This article describes the underlying changes in intra- and interlimb coordination and the resulting load redistribution between the limbs. This enables the practitioner to better understand the changes in movement associated with lameness.
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Weisbecker, V., & Goswami, A. (2010). Brain size, life history, and metabolism at the marsupial/placental dichotomy. Proc. Natl. Acad. Sci. U.S.A., 107(37), 16216–16221.
Abstract: The evolution of mammalian brain size is directly linked with the evolution of the brain's unique structure and performance. Both maternal life history investment traits and basal metabolic rate (BMR) correlate with relative brain size, but current hypotheses regarding the details of these relationships are based largely on placental mammals. Using encephalization quotients, partial correlation analyses, and bivariate regressions relating brain size to maternal investment times and BMR, we provide a direct quantitative comparison of brain size evolution in marsupials and placentals, whose reproduction and metabolism differ extensively. Our results show that the misconception that marsupials are systematically smaller-brained than placentals is driven by the inclusion of one large-brained placental clade, Primates. Marsupial and placental brain size partial correlations differ in that marsupials lack a partial correlation of BMR with brain size. This contradicts hypotheses stating that the maintenance of relatively larger brains requires higher BMRs. We suggest that a positive BMR–brain size correlation is a placental trait related to the intimate physiological contact between mother and offspring during gestation. Marsupials instead achieve brain sizes comparable to placentals through extended lactation. Comparison with avian brain evolution suggests that placental brain size should be constrained due to placentals’ relative precociality, as has been hypothesized for precocial bird hatchlings. We propose that placentals circumvent this constraint because of their focus on gestation, as opposed to the marsupial emphasis on lactation. Marsupials represent a less constrained condition, demonstrating that hypotheses regarding placental brain size evolution cannot be generalized to all mammals.
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Weir, A. A. S., & Kacelnik, A. (2006). A New Caledonian crow (Corvus moneduloides) creatively re-designs tools by bending or unbending aluminium strips. Anim. Cogn., 9(4), 317–334.
Abstract: Previous observations of a New Caledonian crow (Corvus moneduloides) spontaneously bending wire and using it as a hook [Weir et al. (2002) Science 297:981] have prompted questions about the extent to which these animals 'understand' the physical causality involved in how hooks work and how to make them. To approach this issue we examine how the same subject (“Betty”) performed in three experiments with novel material, which needed to be either bent or unbent in order to function to retrieve food. These tasks exclude the possibility of success by repetition of patterns of movement similar to those employed before. Betty quickly developed novel techniques to bend the material, and appropriately modified it on four of five trials when unbending was required. She did not mechanically apply a previously learned set of movements to the new situations, and instead sought new solutions to each problem. However, the details of her behaviour preclude concluding definitely that she understood and planned her actions: in some cases she probed with the unmodified tools before modifying them, or attempted to use the unmodified (unsuitable) end of the tool after modification. Gauging New Caledonian crows' level of understanding is not yet possible, but the observed behaviour is consistent with a partial understanding of physical tasks at a level that exceeds that previously attained by any other non-human subject, including apes.
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Weir, A. A. S., Chappell, J., & Kacelnik, A. (2002). Shaping of hooks in New Caledonian crows. Science, 297(5583), 981.
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Weik, H., Lingk, W., & Altmann, H. J. (1972). [Behavior of individual fatty acids during in-vitro lipolysis and resynthesis in equine depot fat]. Zentralbl Veterinarmed A, 19(8), 677–685.
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Weik, H., & Altmann, J. (1972). The effect of L(+)-lactate on rat and horse adipose tissue in vitro. Zentralbl Veterinarmed A, 19(6), 514–518.
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Weik, H., & Altmann, H. J. (1971). [Behavior of blood lipids during fasting in the horse]. Zentralbl Veterinarmed A, 18(2), 131–138.
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Wehnert, C., Schmidt, A., Möstl, E., Aurich, J., Müller, J., & Aurich, C. (2008). Heart rate and cortisol release in horses during road transport. In IESM 2008.
Abstract: In sport horses, equestrian competitions may lead to increased cortisol release. The competition itself but also a new environment or transport to the events can be considered as stressors. In this study, warmblood sport horses (4-16 years, 4 mares, 2 stallions, 18 geldings) were transported by road for one (t1), 3.5 (t3.5) and 8 hours (t8), (n=8 per group). Heart rate (HR) is an indicator of stress and correlates with cortisol release. Heart rate was recorded with a mobile recording system (f810i, Polar, Kempele, Finland), fixed to a girth around the thorax of the horse and was monitored the day before transport, during transport and 12 hours thereafter. In addition, cortisol metabolite concentrations in faeces were determined in order to analyse adrenocortical activation during transport. Faecal samples were collected three times per day. Cortisol metabolite concentrations in faeces are increased approximately 24 hours after an elevation in plasma cortisol concentrations. Basal HR before transport did not differ between groups (45±2 (SEM) beats/min). During the first 30 min of transport, HR increased significantly (84±6, p<0.001, Kruskal-Wallis-H-test) but did not differ between groups. During the remaining part of the transport, HR was 61±6 beats/min (p<0.001 vs. first 30 min). When HR was analysed for the last 30 min of transport, values for groups t1 and t8 were significantly (p<0.05) higher than in group t3.5. HR decreased to baseline values within less than 30 min after transport and did not differ between groups (30-60 min after transport: 44±3 beats/min). Faecal cortisol metabolite concentrations on the day after transport were elevated compared to pre-transport baseline values in all three groups of horses. Significant differences existed between groups (e.g. 18 hours after transport t1: 91±5, t3.5: 110±18, t8: 136±27 ng/g; p<0.05). Based on HR analysis, horses of group t3.5 had adapted to transport, while the prolonged transport in group t8 again was a stressor. In group t1, which was transported only for one hour, the higher heart during the last 3 min of transport was still part of the initial rise in HR. After an initial increase, heart decreases indicating adaptation of the horse to transport. Cortisol metabolite concentrations in faeces indicate that transport causes adrenocortical activation with the amount of cortisol released depending on the duration of transport. Transport over medium distances appears to no major stressor and a negative impact on the performance of the horse is unlikely. Transport over 8 hours caused the most pronounced cortisol release and HR increases again during the last hours of an 8-hour transport. Transports exceeding this time may temporarily affect the subsequent performance of the horse in equestrian sports.
Supported by Stiftung Forschung für das Pferd
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Weeks, J. W., Crowell-Davis, S. L., & Heusner, G. (2002). Preliminary study of the development of the Flehmen response in Equus caballus. Appl. Anim. Behav. Sci., 78(2-4), 329–335.
Abstract: The flehmen response is commonly seen in most ungulates as well as in several other species (e.g. felids). The behavior is most often thought to be part of the sexual behavioral repertoire of males. One reigning hypothesis suggests that this behavior allows the male to determine the estrous state of a female through the chemosensory functions of the vomeronasal organ. However, females and young of both sexes also exhibit this behavior. Horse foals most frequently show the flehmen response during their first month of life with colts showing the behavior more often than fillies. This study tested the flehmen response on male and female foals throughout their pre-pubertal period. Foals were separately presented estrous and non-estrous urine weekly during the first month of life and then monthly until they were approximately 7 months of age. No significant differences were found between male and female foals for the following variables: latency to flehmen, duration of flehmen, frequency of flehmen and sniffs.
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Weeks, J. W., Crowell-Davis, S. L., Caudle, A. B., & Heusner, G. L. (2000). Aggression and social spacing in light horse (Equus caballus) mares and foals. Appl. Anim. Behav. Sci., 68(4), 319–337.
Abstract: Aggression and social spacing were studied in 14 light horse mares and their foals living at pasture. Focal samples were collected on each mare-foal dyad for 6 to 10.5 h from 2 months of foal age until weaning at approximately 4 months of age. Observations on foals continued until approximately 6 months of age for 7.5 to 10.5 h per foal. Every 2 min the identities of all individuals within 5 m were recorded. All occurrences of agonistic behavior, and the participants, were recorded during the focal samples. In addition, during feeding of supplemental grain, all occurrences of agonistic behavior by all subjects were recorded. Significant correlations were found between mare rank and the rank of foals both prior to and after weaning. Before weaning, the rank of the foal was significantly correlated with birth order. No significant correlation between birth order and foal rank was found for the post-weaning hierarchy. An animal's gender had no significant effect on foal rank or the choice of preferred associate. Both prior to and after weaning, foals associated preferentially with the foal of their dam's most preferred associate. In addition, significant positive correlations were found between rank of mares and foals and the rate at which they directed aggression to other herd members. (C) 2000 Elsevier Science B.V.
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