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Koolhaas, J. M., Korte, S. M., De Boer, S. F., Van Der Vegt, B. J., Van Reenen, C. G., Hopster, H., et al. (1999). Coping styles in animals: current status in behavior and stress-physiology. Neuroscience & Biobehavioral Reviews, 23(7), 925–935.
Abstract: This paper summarizes the current views on coping styles as a useful concept in understanding individual adaptive capacity and vulnerability to stress-related disease. Studies in feral populations indicate the existence of a proactive and a reactive coping style. These coping styles seem to play a role in the population ecology of the species. Despite domestication, genetic selection and inbreeding, the same coping styles can, to some extent, also be observed in laboratory and farm animals. Coping styles are characterized by consistent behavioral and neuroendocrine characteristics, some of which seem to be causally linked to each other. Evidence is accumulating that the two coping styles might explain a differential vulnerability to stress mediated disease due to the differential adaptive value of the two coping styles and the accompanying neuroendocrine differentiation.
Keywords: Coping; Aggression; Stress; Disease; Corticosterone
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Hewitt, S. E., Macdonald, D. W., & Dugdale, H. L. (2009). Context-dependent linear dominance hierarchies in social groups of European badgers, Meles meles. Anim. Behav., 77(1), 161–169.
Abstract: A social hierarchy is generally assumed to exist in those mammalian societies in which the costs and benefits of group living are distributed unevenly among group members. We analysed infrared closed-circuit television footage, collected over 3 years in Wytham Woods, Oxfordshire, to test whether social groups of European badgers have dominance hierarchies. Analysis of directed aggression between dyads revealed linear dominance hierarchies in three social-group-years, but patterns within social groups were not consistent across years. Dominance hierarchies were significantly steeper than random in five out of six social-group-years. In those social-group-years where a linear hierarchy was determined, there was an effect of sex on dominance rank, with females gaining significantly higher rank than males in two social-group-years. Overall, rank was not related to age, nor did it appear to affect the likelihood of an individual being wounded, or an individual's breeding status. The latter resulted from nonorthogonality between sex and breeding status, as there were only two breeding males. Overall, hierarchies were primarily dominated by breeding females, and may occur when breeding competition arises. Relatedness, unreciprocated allogrooming and sequential allomarking were not consistently related to levels of directed aggression across social-group-years. We suggest that dominance structures within European badger groups may be context dependent, with future study required to complete our understanding of where, and when, they arise.
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Hemelrijk, C. K., Wantia, J., & Gygax, L. (2005). The construction of dominance order: comparing performance of five methods using an individual-based model. Behaviour, 142(8), 1043–1064.
Abstract: In studies of animal behaviour investigators correlate dominance with all kinds of behavioural
variables, such as reproductive success and foraging success. Many methods are used to produce a dominance hierarchy from a matrix reflecting the frequency of winning dominance interactions. These different methods produce different hierarchies. However, it is difficult to decide which ranking method is best. In this paper, we offer a new procedure for this decision: we use an individual-based model, called DomWorld, as a test-environment. We choose this model, because it provides access to both the internal dominance values of artificial agents (which reflects their fighting power) and the matrix of winning and losing among them and, in addition, because its behavioural rules are biologically inspired and its group-level patterns resemble those of real primates. We compare statistically the dominance hierarchy based on the internal dominance values of the artificial agents with the dominance hierarchy produced by ranking individuals by (a) their total frequency of winning, (b) their average dominance index, (c) a refined dominance index, the David`s score, (d) the number of subordinates each individual has and (e) a ranking method based on maximizing the linear order of the hierarchy. Because dominance hierarchies may differ depending on group size, type of society, and the interval of study, we compare these ranking methods for these conditions.We study complete samples as well as samples randomly chosen to resemble the limitations of observing real animals. It appears that two methods of medium complexity (the average dominance index and David`s score) lead to hierarchical orders that come closest to the hierarchy based on internal dominance values of the agents. We advocate usage of the average dominance index, because of its computational simplicity. |
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Hartmann, E. (2010). Managing horses in groups to improve horse welfare and human safety. Ph.D. thesis, , .
Abstract: Managing horses in groups to improve horse welfare and human safety
: reactions to mixing and separation Hartmann, Elke (2010) Managing horses in groups to improve horse welfare and human safety . Doctoral diss. Dept. of Animal Environment and Health, SLU. Acta Universitatis agriculturae Sueciae vol. 2010:87. Full text available as: 439 Kb Abstract The aim of this thesis was to investigate whether specific anecdotal concerns related to keeping horses in groups are supported by science and, if so, provide scientifically based recommendations that could be implemented in practice. The aim of studies I and II was to identify methods for mixing unfamiliar horses that could minimise aggressive interactions and associated risk of injury. Results of study I revealed that pre-exposure of young horses in neighbouring boxes tended to lower contact-aggression (e.g. kicks, strikes) and biting behaviour in particular was reduced when the same pair of horses subsequently met in a paddock. This was not found when older horses were mixed (study II). Aggressive behaviour received by a new horse was not significantly different in meetings when it met one other horse compared to meeting two unfamiliar horses at the same time. Removing a horse from a group of four in study III was generally unproblematic. Most horses approached the handler when she was catching the horse and while standing with it in the middle of the paddock. Thus, potential risk may be higher in situations when the handler remains relatively stationary, as other horses of the group have time to approach. Rank did not influence the number of horses following to the paddock gate and interactions between horses were rare. Since horses naïve to social separation may be more difficult to handle away from the group, the objective in study IV was to investigate whether the initial presence of a companion horse would modify responses to separation. Results revealed no significant differences in heart rates and the number of training sessions required when the horses were subsequently trained in the absence of the partner compared to horses trained alone from the start. In summary, results give little support for the original areas of concerns about mixing and separating horses. Risk of injury to both horses and humans should not be overestimated when handling horses in groups, but being aware of potential risk situations and being able to react accordingly is likely to increase horse welfare and human safety. Faculty: Faculty of Veterinary Medicine and Animal Science Keywords: equine, behaviour, welfare, housing, mixing, aggression, injury, separation, habituation, learning Agrovoc terms: horses, behaviour, bites, injurious factors, animal learning, animal welfare, sweden ISBN: 978-91-576-7532-3 Series.: Acta Universitatis agriculturae Sueciae ISSN: 1652-6880 Volume: 2010:87 Papers/manuscripts: I. Hartmann, E., Winther Christensen, J., Keeling, L.J. (2009). Social interactions of unfamiliar horses during paired encounters: Effect of pre-exposure on aggression level and so risk of injury. Applied Animal Behaviour Science 121, 214-221. II. Hartmann, E., Rundgren, M., Keeling, L.J. (in press). Comparison of 3 methods for mixing unfamiliar horses (Equus caballus). Journal of Equine Veterinary Behavior: Clinical Applications and Research. III. Hartmann, E., Søndergaard, E., Keeling, L.J. Identifying potential risk situations for humans when removing horses from groups. Manuscript. IV. Hartmann, E., Christensen, J.W., Keeling, L.J. (in press). Training young horses to social separation: Effect of a companion horse on training efficiency. Equine Veterinary Journal. Number of pages: 75 Year of publication: 2010 Language: eng ID Code: 2396 Deposited By: Hartmann, Elke Deposited On: 08 November 2010 |
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Hartmann, E., Keeling, L. J., & Rundgren, M. (2011). Comparison of 3 methods for mixing unfamiliar horses (Equus caballus). J Vet Behav Clin Appl Res, 6(1), 39–49.
Abstract: Horses are likely to exhibit aggression when meeting for the first time. Therefore, this study compared 3 methods for mixing horses to evaluate their effectiveness in reducing aggressive interactions: (1) mixing pairs of horses in a paddock (P, 10 minutes, 15 tests), (2) introducing 1 unfamiliar horse to a pair of familiar, resident horses in a paddock (PP, 10 minutes, 15 tests), (3) allowing limited physical contact between pairs of horses for a short period of pre-exposure in neighboring boxes (B, 5 minutes, 16 tests) before mixing them in a paddock (BP, 10 minutes 16 tests). A total of 16 Swedish Standardbred mares, aged 6-18 years (mean age ± SD: 11 ± 4.4), were included in the study. Half of the horses were familiar with each other (resident horses, n = 8), whereas the other half were bought in from a variety of sources (unfamiliar horses, n = 8). Social interactions, consisting of behaviors from the sender, the receiver, and the subsequent sender's response, were recorded continuously as frequencies. There were no differences in the frequencies of aggressive behaviors between the 3 mixing methods, including those aggressive behaviors in which physical contact had been attempted (kick, strike). Although resident horses were overall more aggressive (median number of aggressive behaviors per horse, 62; Q1, 36; Q3, 68.5) than unfamiliar horses (median per horse, 4; Q1, 2; Q3, 12.5) during all tests (U = 97, P = 0.003), none of the 62 tests needed to be terminated. Unfamiliar horses did not receive more aggression from resident horses in PP (mean per test ± SD: 5.1 ± 3.1) than in P (mean per test ± SD: 6.4 ± 4.9) (t = 0.63, P = 0.544). However, the behavior “attack” was more frequent in PP (median per test, 2; Q1, 0; Q3, 5) than in P (median per test, 0; Q1, 0; Q3, 1) (U = 282, P = 0.042), and “flee” was more frequent in PP (median per test, 6; Q1, 4; Q3, 8) than in P (median per test, 1; Q1, 0; Q3, 6) (U = 290, P = 0.018). Pre-exposure in boxes did not reduce aggression in BP (median per test, 7; Q1, 4.3; Q3, 11.8) as compared with P (median per test, 6; Q1, 2; Q3, 16) (U = 264, P = 0.767), but during pre-exposure in B tests, horses exchanged more nonaggressive (median per test, 2; Q1, 0.3; Q3, 4) than aggressive (median frequency of aggressive behavior, 0; Q1, 0; Q3, 1) (W = 71, P = 0.013) and mixed interactions (median per test, 0; Q1, 0; Q3, 1) (W = 92, P = 0.016) through the opening. Results suggest mixing an unfamiliar horse with 2 resident horses at the same time instead of one by one may be preferable. In this way, the total aggression received by the unfamiliar horse will potentially be less, even though aggressive interactions may be more intense.
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Vervaecke, H., Stevens, J., Vandemoortele, H., Sigurjönsdöttir, H., & De Vries, H. (2007). Aggression and dominance in matched groups of subadult Icelandic horses (Equus caballus). J. Ethol., 25(3), 239–248.
Abstract: Abstract We studied sex differences in the nature of aggression and dominance behaviour in two newly formed groups of 1-year-old Icelandic horses. One herd contained nine geldings, the other nine mares. The groups were matched with regard to dominance-determining traits such as age, weaning age, composition of native herd, social experience, genetic origin, body condition and maternal dominance status. High-ranking individuals of both sexes were more aggressive, high-ranking males were older, and high-ranking females had a better body condition. Frequencies of aggressions were similar in both groups. The mares reacted significantly more by showing submission upon an aggression rather than by not responding or by escalating the aggression. For the geldings, this difference was not observed due to a lower tendency to submit. A linear dominance hierarchy was found in both groups. David`s scores provided additional information regarding cardinal rank distances and were used to calculate steepness of hierarchies. The female hierarchy was somewhat steeper compared to the male hierarchy, suggesting somewhat lower despotism among males. This was mainly a consequence of the lower unidirectionality in male submission. Male contests occurred predominantly between dyads at top and mid positions, suggesting a low degree of acceptance of the hierarchy.
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VanDierendonck, M. C. (2006). Social relationships in a group of horses without a mature stallion (Vol. Chapter 4). Universiteit Utrecht.
Abstract: Feral horses are social animals, which have to rely on survival strategies centered on the formation of cohesive social bonds within their bands. Many problems in the husbandry of social animals such as horses, are due to the fact that the limits of their adaptive abilities are exceeded. Evidence suggests that the fundamental social characteristics of domestic horses have remained relatively unchanged. The social structure, social strategies and social interactions were investigated (3 non-consecutive years, 24 hr per day for several weeks) in long term established groups of domestic horses (mares and geldings of all ages) and a few small introduced groups, kept in (semi)natural environments. The general aim was to investigate the social needs of domestic horses. The social life of domestic horses was characterised by long lasting bonds with preferred partners which were established and maintained by allogrooming, play, proximity and dominance behaviours. Bonding partners were mainly found within the same sex-age group, but adult geldings also bonded with sub-adult mares and geldings. Adult mares were clustered in a group, while the other animals formed a second group. Among the adult mares, subgroups according to reproductive state were formed. Individuals regulated their social network by interfering with interactions between other members of the herd, which in itself is complex. An intervention is a behavioural action of one animal that actively interferes with an ongoing interaction between a dyad with the apparent aim of altering that interaction. This was verified by post-hoc analyses of disturbed and undisturbed interactions. Interventions in allogrooming or play were performed significantly more often when at least one member of the initial dyad was a preferred partner of, or familiar to (within the small introduced bands) the intervener. The stronger the preferred association in allogrooming between the intervener and member(s) of the initial dyad, the higher the probability the intervener would displace one initial member and continue allogrooming with the other. Just five behaviours were extracted which reliably reflected the dominance relations among horses. Aggression with the hind quarters was used both offensively and defensively and therefore not suitable as a reliable parameter. Individual dominance relationships were related to social experience. The implications of these findings for horse husbandry were assessed. It is argued that the execution of affiliative behaviours may be rewarding in itself, and therefore always will be a highly motivated behaviour. It is shown that social positive physical interactions (allogrooming, play) with other horses is an ethological need and therefore indispensable in modern husbandry systems. Ethological needs are so important for the animal that husbandry systems that lack the possibilities to execute such behaviours will cause chronic stress. It is concluded that all horses need physical social contact, and that horses, which lack appropriate social learning experiences during ontogeny, may be hampered in their social functioning later in life. Solutions for problems, including dominance problems, in individual social housing and group housing are presented.
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VanDierendonck, M. C. (2006). Diff erences in social behaviour between late pregnant, post-partum and barren mares in a herd of Icelandic horses (Vol. Chapter 5). Ph.D. thesis, , Universiteit Utrecht.
Abstract: Feral horses are social animals, which have to rely on survival strategies centered on the formation of cohesive social bonds within their bands. Many problems in the husbandry of social animals such as horses, are due to the fact that the limits of their adaptive abilities are exceeded. Evidence suggests that the fundamental social characteristics of domestic horses have remained relatively unchanged. The social structure, social strategies and social interactions were investigated (3 non-consecutive years, 24 hr per day for several weeks) in long term established groups of domestic horses (mares and geldings of all ages) and a few small introduced groups, kept in (semi)natural environments. The general aim was to investigate the social needs of domestic horses. The social life of domestic horses was characterised by long lasting bonds with preferred partners which were established and maintained by allogrooming, play, proximity and dominance behaviours. Bonding partners were mainly found within the same sex-age group, but adult geldings also bonded with sub-adult mares and geldings. Adult mares were clustered in a group, while the other animals formed a second group. Among the adult mares, subgroups according to reproductive state were formed. Individuals regulated their social network by interfering with interactions between other members of the herd, which in itself is complex. An intervention is a behavioural action of one animal that actively interferes with an ongoing interaction between a dyad with the apparent aim of altering that interaction. This was verified by post-hoc analyses of disturbed and undisturbed interactions. Interventions in allogrooming or play were performed significantly more often when at least one member of the initial dyad was a preferred partner of, or familiar to (within the small introduced bands) the intervener. The stronger the preferred association in allogrooming between the intervener and member(s) of the initial dyad, the higher the probability the intervener would displace one initial member and continue allogrooming with the other. Just five behaviours were extracted which reliably reflected the dominance relations among horses. Aggression with the hind quarters was used both offensively and defensively and therefore not suitable as a reliable parameter. Individual dominance relationships were related to social experience. The implications of these findings for horse husbandry were assessed. It is argued that the execution of affiliative behaviours may be rewarding in itself, and therefore always will be a highly motivated behaviour. It is shown that social positive physical interactions (allogrooming, play) with other horses is an ethological need and therefore indispensable in modern husbandry systems. Ethological needs are so important for the animal that husbandry systems that lack the possibilities to execute such behaviours will cause chronic stress. It is concluded that all horses need physical social contact, and that horses, which lack appropriate social learning experiences during ontogeny, may be hampered in their social functioning later in life. Solutions for problems, including dominance problems, in individual social housing and group housing are presented.
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VanDierendonck, M. C. (2006). Interventions in social behaviour in a herd of mares and geldings (Vol. Chapter 6). Universiteit Utrecht.
Abstract: Feral horses are social animals, which have to rely on survival strategies centered on the formation of cohesive social bonds within their bands. Many problems in the husbandry of social animals such as horses, are due to the fact that the limits of their adaptive abilities are exceeded. Evidence suggests that the fundamental social characteristics of domestic horses have remained relatively unchanged. The social structure, social strategies and social interactions were investigated (3 non-consecutive years, 24 hr per day for several weeks) in long term established groups of domestic horses (mares and geldings of all ages) and a few small introduced groups, kept in (semi)natural environments. The general aim was to investigate the social needs of domestic horses. The social life of domestic horses was characterised by long lasting bonds with preferred partners which were established and maintained by allogrooming, play, proximity and dominance behaviours. Bonding partners were mainly found within the same sex-age group, but adult geldings also bonded with sub-adult mares and geldings. Adult mares were clustered in a group, while the other animals formed a second group. Among the adult mares, subgroups according to reproductive state were formed. Individuals regulated their social network by interfering with interactions between other members of the herd, which in itself is complex. An intervention is a behavioural action of one animal that actively interferes with an ongoing interaction between a dyad with the apparent aim of altering that interaction. This was verified by post-hoc analyses of disturbed and undisturbed interactions. Interventions in allogrooming or play were performed significantly more often when at least one member of the initial dyad was a preferred partner of, or familiar to (within the small introduced bands) the intervener. The stronger the preferred association in allogrooming between the intervener and member(s) of the initial dyad, the higher the probability the intervener would displace one initial member and continue allogrooming with the other. Just five behaviours were extracted which reliably reflected the dominance relations among horses. Aggression with the hind quarters was used both offensively and defensively and therefore not suitable as a reliable parameter. Individual dominance relationships were related to social experience. The implications of these findings for horse husbandry were assessed. It is argued that the execution of affiliative behaviours may be rewarding in itself, and therefore always will be a highly motivated behaviour. It is shown that social positive physical interactions (allogrooming, play) with other horses is an ethological need and therefore indispensable in modern husbandry systems. Ethological needs are so important for the animal that husbandry systems that lack the possibilities to execute such behaviours will cause chronic stress. It is concluded that all horses need physical social contact, and that horses, which lack appropriate social learning experiences during ontogeny, may be hampered in their social functioning later in life. Solutions for problems, including dominance problems, in individual social housing and group housing are presented.
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VanDierendonck, M. C. (2006). General Discussion (Vol. Chapter 7). Universiteit Utrecht.
Abstract: Feral horses are social animals, which have to rely on survival strategies centered on the formation of cohesive social bonds within their bands. Many problems in the husbandry of social animals such as horses, are due to the fact that the limits of their adaptive abilities are exceeded. Evidence suggests that the fundamental social characteristics of domestic horses have remained relatively unchanged. The social structure, social strategies and social interactions were investigated (3 non-consecutive years, 24 hr per day for several weeks) in long term established groups of domestic horses (mares and geldings of all ages) and a few small introduced groups, kept in (semi)natural environments. The general aim was to investigate the social needs of domestic horses. The social life of domestic horses was characterised by long lasting bonds with preferred partners which were established and maintained by allogrooming, play, proximity and dominance behaviours. Bonding partners were mainly found within the same sex-age group, but adult geldings also bonded with sub-adult mares and geldings. Adult mares were clustered in a group, while the other animals formed a second group. Among the adult mares, subgroups according to reproductive state were formed. Individuals regulated their social network by interfering with interactions between other members of the herd, which in itself is complex. An intervention is a behavioural action of one animal that actively interferes with an ongoing interaction between a dyad with the apparent aim of altering that interaction. This was verified by post-hoc analyses of disturbed and undisturbed interactions. Interventions in allogrooming or play were performed significantly more often when at least one member of the initial dyad was a preferred partner of, or familiar to (within the small introduced bands) the intervener. The stronger the preferred association in allogrooming between the intervener and member(s) of the initial dyad, the higher the probability the intervener would displace one initial member and continue allogrooming with the other. Just five behaviours were extracted which reliably reflected the dominance relations among horses. Aggression with the hind quarters was used both offensively and defensively and therefore not suitable as a reliable parameter. Individual dominance relationships were related to social experience. The implications of these findings for horse husbandry were assessed. It is argued that the execution of affiliative behaviours may be rewarding in itself, and therefore always will be a highly motivated behaviour. It is shown that social positive physical interactions (allogrooming, play) with other horses is an ethological need and therefore indispensable in modern husbandry systems. Ethological needs are so important for the animal that husbandry systems that lack the possibilities to execute such behaviours will cause chronic stress. It is concluded that all horses need physical social contact, and that horses, which lack appropriate social learning experiences during ontogeny, may be hampered in their social functioning later in life. Solutions for problems, including dominance problems, in individual social housing and group housing are presented.
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