| Records |
| Author |
Devenport, J.A.; Patterson, M.R.; Devenport, L.D. |
| Title |
Dynamic averaging and foraging decisions in horses (Equus callabus) |
Type |
Journal Article |
| Year |
2005 |
Publication |
Journal of Comparative psychology |
Abbreviated Journal |
J. Comp. Psychol. |
| Volume |
119 |
Issue |
3 |
Pages |
352-358 |
| Keywords |
Animals; *Decision Making; *Feeding Behavior; Female; Horses/*psychology; Male; *Memory, Short-Term; Motivation; Orientation; *Social Environment |
| Abstract |
The variability of most environments taxes foraging decisions by increasing the uncertainty of the information available. One solution to the problem is to use dynamic averaging, as do some granivores and carnivores. Arguably, the same strategy could be useful for grazing herbivores, even though their food renews and is more homogeneously distributed. Horses (Equus callabus) were given choices between variable patches after short or long delays. When patch information was current, horses returned to the patch that was recently best, whereas those without current information matched choices to the long-term average values of the patches. These results demonstrate that a grazing species uses dynamic averaging and indicate that, like granivores and carnivores, they can use temporal weighting to optimize foraging decisions. |
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Department of Psychology, University of Central Oklahoma, 73034, USA. jdevenport@ucok.edu |
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0735-7036 |
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PMID:16131264 |
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refbase @ user @ |
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752 |
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| Author |
Cant, M.A.; Field, J. |
| Title |
Helping effort in a dominance hierarchy |
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Journal Article |
| Year |
2005 |
Publication |
Behavioral Ecology |
Abbreviated Journal |
Behav. Ecol. |
| Volume |
16 |
Issue |
4 |
Pages |
708-715 |
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| Abstract |
In many cooperatively breeding species, group members form a dominance hierarchy or queue to inherit the position of breeder. Models aimed at understanding individual variation in helping behavior, however, rarely take into account the effect of dominance rank on expected future reproductive success and thus the potential direct fitness costs of helping. Here we develop a kin-selection model of helping behavior in multimember groups in which only the highest ranking individual breeds. Each group member can invest in the dominant's offspring at a cost to its own survivorship. The model predicts that lower ranked subordinates, who have a smaller probability of inheriting the group, should work harder than higher ranked subordinates. This prediction holds regardless of whether the intrinsic mortality rate of subordinates increases or decreases with rank. The prediction does not necessarily hold, however, where the costs of helping are higher for lower ranked individuals: a situation that may be common in vertebrates. The model makes two further testable predictions: that the helping effort of an individual of given rank should be lower in larger groups, and the reproductive success of dominants should be greater where group members are more closely related. Empirical evidence for these predictions is discussed. We argue that the effects of rank on stable helping effort may explain why attempts to correlate individual helping effort with relatedness in cooperatively breeding species have met with limited success. |
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10.1093/beheco/ari051 |
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no |
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refbase @ user @ |
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760 |
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Vahl, W.K.; Lok, T.; van der Meer, J.; Piersma, T.; Weissing, F.J. |
| Title |
Spatial clumping of food and social dominance affect interference competition among ruddy turnstones |
Type |
Journal Article |
| Year |
2005 |
Publication |
Behavioral Ecology |
Abbreviated Journal |
Behav. Ecol. |
| Volume |
16 |
Issue |
5 |
Pages |
834-844 |
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| Abstract |
In studying the success of foraging animals, studies of interference competition have put emphasis on effects of competitor density, whereas studies of resource defense have focused on the effects of the spatial distribution of food within patches. Very few studies have looked at both factors simultaneously, that is, determined whether the effects of competitor density on foraging success depend on the spatial distribution of food. We studied the behavior and the foraging success of ruddy turnstones (Arenaria interpres) using an experiment in which we varied both the presence of a competitor and the food distribution. Because turnstones may differ strongly in their relative dominance status, we also experimentally varied the foragers' relative dominance status. We found that the presence of a competitor only reduced the foraging success of subordinate birds foraging at the clumped food distribution. At this condition, dominant and subordinate birds differed markedly in their foraging success. Contrary to our expectations, we did not observe more agonistic behavior at the clumped food distribution. This indicates that the amount of agonistic behavior observed may be a bad indicator of interference effects. These findings have specific implications for models of interference competition. Most notably they show that the effects of competitor density on agonistic behavior and foraging success may well depend on the spatial distribution of food and the foragers' relative dominance status. Additionally, our results suggest that social dominance will not be fully understood without considering long-term processes such as the formation and maintenance of social dominance hierarchies. |
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10.1093/beheco/ari067 |
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no |
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refbase @ user @ |
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761 |
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| Author |
Haring, H. |
| Title |
Development, level and prospects of the german horse breeding |
Type |
Journal Article |
| Year |
2005 |
Publication |
Zuechtungskunde |
Abbreviated Journal |
Zuechtungskunde |
| Volume |
77 |
Issue |
6 |
Pages |
490-495 |
| Keywords |
Breeding program; Breeding/Member association; Change of structure; Estimation of breeding values; Fédération Equestre Nationale (FN)/German Equestrian Federation; Step of selection; Equidae; Equus caballus |
| Abstract |
The economic impact of the horses of the Federal Republic of Germany has gone up, the statistic numerals verify obviously that Germany took pride of place in Europe in terms of numbers of riders as well as numbers of horses. Successes of German branded horses let their breeders reach the summit worldwide. The carefully agreed breeding programme connects practical cognitions with those of science and permits the leading breeding areas unobstructed space to set their own priorities. Globalisation and rised demand of customers forces breeding associations towards a far-reaching reorganisation because just large powerful institutions can meet these requirements. An end of this process, which scarcely has just begun, cannot yet be conceivable seen. – Eugen Ulmer KG, Stuttgart. |
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Deutsche Reiterliche Vereinigung e. V., 48229 Warendorf, Germany |
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00445401 (Issn) |
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Cited By (since 1996): 1; Export Date: 21 April 2007; Source: Scopus; Language of Original Document: German; Correspondence Address: Haring, H.; Deutsche Reiterliche Vereinigung e. V. 48229 Warendorf, Germany; email: Hharing@fn-dokr.de |
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no |
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refbase @ user @ |
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791 |
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| Author |
Lansade, L.; Bertrand, M.; Bouissou, M.-F. |
| Title |
Effects of neonatal handling on subsequent manageability, reactivity and learning ability of foals |
Type |
Journal Article |
| Year |
2005 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
92 |
Issue |
1-2 |
Pages |
143-158 |
| Keywords |
Horse; Neonatal handling; Manageability; Emotional reactivity; Learning-ability; Human-animal relationship |
| Abstract |
Behaviour is an important factor to be taken into account in the various uses of horses. Today horses are mainly used for sport and leisure activities. They should therefore be easy to manage, calm and not fearful. Early handling is known to improve manageability and learning ability and to reduce fearfulness in various species. It has become fashionable in the horse industry to use an early training procedure, referred to as “imprint training”, which is said to produce durable if not permanent effects. However, no studies concerning the long-term effects of such neonatal handling have been carried out in horses. The present study examines the short- and long-term effects of neonatal handling on manageability, general reactivity and learning ability of foals. Twenty-six Welsh foals were studied: 13 were handled daily for 14 days from birth and 13 were non-handled controls. The handling procedure consisted of fitting a halter, gently patting all parts of each foal's body, picking up feet and leading over 40 m. Two days, 3 months, 6 months and 1 year after the end of the handling period, foals underwent behavioural tests to measure their manageability and various aspects of their reactivity. The results showed that neonatal handling has only short-term effects on manageability: 2 days after the handling period, handled animals were significantly easier to handle than controls for the four parameters measured during this test (time to fit a halter, time to pick up feet, walk ratio that is time during which foal walks under constraint/total time measured during leading and number of defensive reactions). Two parameters (time to fit a halter and walk ratio) were still lower in handled foals than in non-handled foals 3 months later and only one 6 months later (walk ratio). One year later there was no difference between groups. In addition, there was no effect of handling on reactivity at any time of testing or in any of the tests (reaction to isolation from conspecifics, presence of a human, presence of a novel object and to a surprise effect). Finally, neonatal handling did not improve the spatial or discriminative learning abilities measured at 14 months of age. To conclude, the effects of neonatal handling are only temporary. |
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no |
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refbase @ user @ |
Serial |
841 |
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Uehara, T.; Yokomizo, H.; Iwasa, Y. |
| Title |
Mate-choice copying as Bayesian decision making |
Type |
Journal Article |
| Year |
2005 |
Publication |
The American naturalist |
Abbreviated Journal |
Am Nat |
| Volume |
165 |
Issue |
3 |
Pages |
403-410 |
| Keywords |
Animals; *Bayes Theorem; *Choice Behavior; Female; Male; *Models, Biological; *Sexual Behavior, Animal |
| Abstract |
Mate-choice copying by females has been reported in fishes (e.g., guppies) and lekking birds. Presumably, females assess males' quality using both information from direct observation of males and information acquired by observing other females' choices. Here, we study mathematically the conditions under which mate-choice copying is advantageous on the basis of Bayesian decision theory. A female may observe the mate choice of another female, called the model female, who has performed an optimal choice based on her own judgment. The conditions required for the focal female to choose the same mate as that chosen by the model female should depend on the male's appearance to her, the reliability of her own judgment of male quality, and the reliability of the model females. When three or more females are involved, the optimal mate choice critically depends on whether multiple model females make decisions independently or they themselves copy the choices of others. If two equally reliable females choose different males, the choice of the second female, made knowing the choice of the first, should have a stronger effect on the choice of the third (focal) female. This “last-choice precedence” should be tested experimentally. |
| Address |
Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan. uehara@bio-math.biology.kyushu-u.ac.jp |
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1537-5323 |
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PMID:15729669 |
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no |
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1821 |
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McGreevy, P.D.; Rogers, L.J. |
| Title |
Motor and sensory laterality in thoroughbred horses |
Type |
Journal Article |
| Year |
2005 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
92 |
Issue |
4 |
Pages |
337-352 |
| Keywords |
Horse; Lateralisation; Training; Olfaction; Forelimb preference |
| Abstract |
We investigated lateralisation in horses because it is likely to be important in training and athletic performance. Thoroughbred horses (n = 106) were observed every 60 s for 2 h, when they were at pasture, and the position of the forelimbs in relation to one another was recorded. There was a population bias skewed to standing with the left forelimb advanced over the right (i.e. directional lateralisation). Using the first 50 observations, the distribution of preferences was 43 significantly left, 10 significantly right with 53 being non-significant (i.e. ambidextextrous). The strength of motor bias increased with age, suggesting maturation or an influence of training. The horses were also presented with an olfactory stimulus (stallion faeces) to score the tendency to use one nostril rather than the other. A significant preference to use the right nostril first was shown in horses under 4 years of age (n = 61) but not in older horses. Of the 157 horses tested for nostril bias, 76 had been assessed for motor bias and so were used for analysis of the relationship between laterality in the two modalities. There was no significant relationship between direction of foreleg motor bias and first nostril used, total number of inhalations or laterality index of nostril use. The absence of a correlation between laterality of nostril use and motor bias indicates that lateralisation of the equine brain occurs on at least two levels of neural organisation--sensory and motor--a finding that is consistent with other examples of lateralisation in species that have been examined in more detail. |
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Equine Behaviour @ team @ room 3.029 |
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1827 |
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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 |
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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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0022-0949 |
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PMID:15634844 |
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1895 |
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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 |
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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 |
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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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1042-7260 |
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PMID:17323569 |
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2023 |
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Dumont, B.; Boissy, A.; Achard, C.; Sibbald, A.M.; Erhard, H.W. |
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Consistency of animal order in spontaneous group movements allows the measurement of leadership in a group of grazing heifers |
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Journal Article |
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2005 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
| Volume |
95 |
Issue |
1-2 |
Pages |
55-66 |
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Cattle; Grazing; Leadership; Movement order; Walking |
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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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Equine Behaviour @ team @ room B 3.029 |
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2027 |
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