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Rocha, A. D. de L., Menescal-de-Oliveira, L., & da Silva, L. F. S. (2017). Effects of human contact and intra-specific social learning on tonic immobility in guinea pigs, Cavia porcellus. Appl. Anim. Behav. Sci., .
Abstract: Abstract Social learning is the capacity of animals to acquire adaptive information from others. In the case of fear responses, animals can learn fearful or non-fearful responses by observing the behavior of conspecifics. Tonic immobility (TI) is an anti-predatory behavior elicited during intense fear situations. Studies have revealed that regular contact with humans can reduce TI responses in animals. In our study, we evaluated the effect of human contact on the TI responses in guinea pigs. We also evaluated the effect of cohabitation (non-fearful animals with fearful animals) on their TI responses. To achieve this, we measured the TI responses induced by postural inversion and restraint in guinea pigs as a result of different treatments. In our first experiment, we determined the effect of human contact on TI responses by establishing 3 treatment groups: no contact, handled, and habituated. In our second experiment, we addressed the effect of social learning on TI response by testing TI response in habituated, and unhabituated animals that had cohabitated for 10 days. In the first experiment, 10 days of either handling or habituation did not prevent TI in guinea pigs, but habituation did increase latency [F(2,119) = 14.19; p < 0.0001] and handling or habituation decrease duration [F(2,119) = 15.01; p < 0.0001] of the TI behavior in the guinea pigs. In the second experiment, the cohabitation of unhabituated and habituated animals reduced TI duration [F(2,93) = 5.058; p < 0.008]. These data suggest that both forms of human interaction can reduce experimenter fear in guinea pigs. It therefore seems that unhabituated guinea pigs learn not to fear the experimenter by cohabitating with habituated guinea pigs.
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Keeling, L. J., Bøe, K. E., Christensen, J. W., Hyyppä, S., Jansson, H., Jørgensen, G. H. M., et al. Injury incidence, reactivity and ease of handling of horses kept in groups: a matched case control study in four Nordic countries. Appl Anim Behav Sci, .
Abstract: Abstract There is increasing interest in keeping horses in groups, but progress is hampered by a lack of knowledge about which horses can and should be kept together. Therefore, our objective was to investigate the effect of group composition on the occurrence of injuries among horses, the ease of removing horses from groups and horses’ reactivity to a fearful stimulus. Using a matched case control design, 61 groups of horses were studied in Denmark, Norway, Finland and Sweden. They were allocated into groups of similar or different age and sex or where membership changed regularly or remained stable. Injuries were recorded before mixing the horses into treatment groups, the day after mixing and four weeks later. Reactivity of horses to a moving novel object and the behaviour of a horse being removed from its group and the reactions of other group members towards this horse and the handler were evaluated. It was hypothesized that a more socially variable group composition has beneficial effects on behaviour, ease of handling and reducing reactivity whereas frequent changes in group composition has negative consequences, resulting in more injuries. We found that differences in treatment effects were mainly related to breed, rather than group composition. Icelandic horses reacted less to the movement of the novel object (P = 0.007) and approached it more afterwards (P = 0.04). They also had fewer new injuries than warmbloods following mixing (P < 0.001) and fewer than all other groups 4 weeks later (P < 0.01). Most new injuries after mixing were minor and recorded on the horse’s head, chest, hind legs and rump. In conclusion, variations in sex and age composition of the group had little effect on injury level, reactivity and ease of handling compared to the general effect of breed. Concerns about the risk of severe injuries associated with keeping horses in groups are probably overestimated. Thus, we propose that horses can be successfully kept in groups of different sex and age composition.
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Giles, S. L., Nicol, C. J., Harris, P. A., & Rands, S. A. (2015). Dominance rank is associated with body condition in outdoor-living domestic horses (Equus caballus). Applied Animal Behaviour Science, .
Abstract: Abstract The aim of our study was to explore the association between dominance rank and body condition in outdoor group-living domestic horses, Equus caballus. Social interactions were recorded using a video camera during a feeding test, applied to 203 horses in 42 herds. Dominance rank was assigned to 194 individuals. The outcome variable body condition score (BCS) was recorded using a 9-point scale. The variables age and height were recorded and considered as potential confounders or effect modifiers. Results were analysed using multivariable linear and logistic regression techniques, controlling for herd group as a random effect. More dominant (p = 0.001) individuals generally had a higher body condition score (p = 0.001) and this association was entirely independent of age and height. In addition, a greater proportion of dominant individuals fell into the obese category (BCS >= 7/9, p = 0.005). There were more displacement encounters and a greater level of interactivity in herds that had less variation in age and height, lending strength to the hypothesis that phenotypic variation may aid cohesion in group-living species. In addition there was a strong quadratic relationship between age and dominance rank (p < 0.001), where middle-aged individuals were most likely to be dominant. These results are the first to link behavioural predictors to body condition and obesity status in horses and should prompt the future consideration of behavioural and social factors when evaluating clinical disease risk in group-living animals.
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Austin, N. P., & Rogers, L. J. (2014). Lateralization of agonistic and vigilance responses in Przewalski horses (Equus przewalskii). Applied Animal Behaviour Science, 151, 43–50.
Abstract: tEye and limb preferences were scored in the closest undomesticated relative of Equuscaballus using the same methods as used previously to study laterality in feral horses.Observations were made of 33 Przewalski horses (Equus ferus przewalskii) (male N = 20,female N = 13) living under natural social conditions on a large reserve in France. Signifi-cant left-eye/side biases were found in agonistic interactions within harem bands (M ± SEbias to left 58% ± 0.01 for threats, P < 0.001; 68% ± 0.05 for attacks; P < 0.001) and in stallionfights (threats, 52% ± 0.01 left, P < 0.001; attacks, 63% ± 0.02 left, P < 0.001): as many as 80%of the horses were significantly lateralized in attack responses within harem bands. Lat-erality of vigilance was measured as lifting up the head from grazing and turning it to theleft or right side: a directional bias to the left was found (M ± SE 53% ± 0.02 left, P < 0.001).Side bias in reactivity was calculated as the percent of head lifts above the level of thewithers on the left or right side and this was also left side biased (M ± SE 73% ± 0.03 left,P < 0.001). These results indicate right-hemisphere specialization for control of aggressionand responses to novelty. The left bias in attack scores within harem bands was strongerin males than females (P = 0.024) and in immature than adult horses (P = 0.032). Immaturehorses were also more strongly lateralized than adults in vigilance scores (P = 0.022), whichmay suggest that experience reduces these side biases. Our results show that Przewalskihorses exhibit left eye preferences, as do feral horses, and do so even more strongly thanferal horses. Considering feral and Przewalski horses together, we deduce that ancestralhorses had similar lateral biases. Also similar to feral horses, the Przewalski horses showedno significant forelimb preference at the group level or in the majority of horses at theindividual level, confirming the hypothesis that previously reported limb preferences indomestic breeds are entrained or generated by breed-specific selection.
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Granquist, S. M., Thorhallsdottir, A. G., & Sigurjonsdottir, H. (2012). The effect of stallions on social interactions in domestic and semi feral harems. Applied Animal Behaviour Science, 141(1–2), 49–56.
Abstract: Earlier research indicates that stallions may supress interactions of their harem members, leading to less stable hierarchies and friendship bonds in harems compared to non-stallion groups. In this paper, the effect of the presense of a stallion on the social behaviour of mares was studied by comparing six harems containing stallions to four mixed sex groups not containing stallions. Both temporary and permanent harems were studied, giving the possibility to investigate the effect of group stability on social interactions. A significant linear hierarchy was found in all non-stallion groups that were used for comparison, while the hierarchies were only found to be linear in three of the six harems containing stallions (Landaus h', p < 0.05). Aggression rate was lower (t-test, p < 0.05) and fewer friendship bonds (G-test, p < 0.0001) were found within the harems, compared to the groups without stallions. Stallions seldom intervene directly in interactions between harem members. Thus, our results give support to the hypothesis that stallions may suppress interactions of harem members, but in a more indirect way than with direct interference. In addition, our results give support for earlier findings that aggression rate may be affected by group stability. We found a higher aggression rate in the temporary harems compared to the permanent harems (Kruskal–Wallis, p < 0.05) and in the temporary non-stallion group compared to the permanent non-stallion group. The results have significance for further research on social structure of mammals, and may be applied in management of domestic animals.
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Young, T., Creighton, E., Smith, T., & Hosie, C. (2012). A novel scale of behavioural indicators of stress for use with domestic horses. Applied Animal Behaviour Science, 140(1–2), 33–43.
Abstract: Behaviour scores (BS) offer non-invasive, objective and easy to use ways of assessing welfare in animals. Their development has, however, largely focused on behavioural reactions to stressful events (often induced), and little use of physiological measures has been made to underpin and validate the behavioural measures. This study aimed to develop a physiologically validated scale of behavioural indicators of stress for the purpose of welfare assessment in stabled domestic horses. To achieve this, behavioural and physiological data were collected from 32 horses that underwent routine husbandry procedures. Principal component analysis (PCA) of the behavioural and physiological data revealed three meaningful components that were used as the basis of the scale. Analysis of video clips of the horses’ responses to the husbandry procedures was undertaken by a panel of equestrian industry professionals using a free choice profiling (FCP) methodology. These results were added to the scale along with key definitions from relevant literature. Salivary cortisol levels were significantly correlated with the BS confirming the scale was meaningful and reflected physiological stress. The scale offers an easy to use ‘tool’ for rapid, reliable non-invasive welfare assessment in horses, and reduces the need for potentially invasive physiological measures.
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Van de Weerd, H. A., Seaman, S., Wheeler, K., Goddard, P., & Mclean, B. (2012). Use of artificial drinkers by unhandled semi-feral ponies. Appl. Anim. Behav. Sci., 139(1-2), 86–95.
Abstract: This study investigated drinking behaviour of unhandled, semi-feral Dartmoor ponies. Aspects studied were drinking behaviour, latency to drink from novel unfamiliar drinkers after transport, preferences for different types of artificial water drinkers, effects of mixing with unfamiliar ponies and group size, on drinking behaviour, and the effect of a simulated market on the latency to drink. Ponies were tested in groups of three or six animals, or as individuals in test pens that were equipped with three water drinkers: bucket, automatic drinking bowl, flowing water trough. Behaviour was recorded using time-lapse video. An individual pony drank on average 10 l per day. Ponies also drank, but at a lower rate, during the night. The latencies to drink after 4.5 h of transport showed large variation, but most ponies drank within the first hour after being transported (all groups 80.5 ± 32.94 min, mean ± SEM). In the individual choice tests, the preferred drinkers were the bucket and the flowing water trough, but not the automatic drinking bowl (drinking time 25.2 ± 4.66, 11.5 ± 4.26, 2.4 ± 2.23 min for bucket, trough and bowl respectively, mean ± SEM; paired t-tests, bowl versus other drinkers, all tests p < 0.02). A possible reason for the avoidance of the automatic bowl was the noise it made when filling. After mixing a group of three ponies with a group of three unfamiliar animals, the ponies did not express their individual drinker preferences anymore. The use of the previously preferred bucket decreased significantly and the use of the initially, non-preferred, bowl increased significantly. This was likely caused by the fact that ponies were either intentionally or accidentally obstructing drinkers in certain areas of the pen and unfamiliar ponies did not want to push past them. In the simulated market, the differences in latencies to drink between ponies in the home pen and market groups did not reach significance. No significant effect of group size (groups of three versus six ponies) on drinking behaviour was detected. The results have implications for situations where only automatic water bowls are provided, such as during pony sales at livestock markets. Preventing ponies from expressing their drinking choice, either by offering non-preferred drinkers or by mixing with unfamiliar animals, could adversely affect their welfare especially if this happens in conjunction with other stressful events such as transport and markets, and potentially weaning.
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Fureix, C., Bourjade, M., Henry, S., Sankey, C., & Hausberger, M. (2012). Exploring aggression regulation in managed groups of horses Equus caballus. Appl. Anim. Behav. Sci., 138(3–4), 216–228.
Abstract: Horses are highly social animals that have evolved to live in social groups. However, in modern husbandry systems, single housing prevails where horses experience social isolation, a challenge-to-welfare factor. One major reason for this single housing is the owners’ concerns that horses may injure each other during aggressive encounters. However, in natural conditions, serious injuries due to aggressive encounters are rare. What could therefore explain the claimed risks of group living for domestic horses? Basing our questioning on the current knowledge of the social life of horses in natural conditions, we review different practices that may lead to higher levels of aggression in horses and propose practical solutions. Observations of natural and feral horses mostly indicate a predominance of low frequencies and mild forms of aggression, based on subtle communication signals and ritualized displays and made possible by group stability (i.e. stable composition), dominance hierarchy and learning of appropriate social skills by young horses. Obviously, adults play a major role here in canalizing undesirable behaviours, and social experience during development, associated with a diversity of social partners, seems to be a prerequisite for the young horse to become socially skilled. Given the natural propensity of horses to have a regulation of aggression in groups, the tendency to display more aggression in groups of domestic horses under some management practices seems clearly related to the conditions offered. We therefore review the managing practices that could trigger aggressiveness in horses. Non social practices (space, resource availability) and social practices (group size, stability of membership, composition and opportunities for social experiences during development) in groups of domestic horses are discussed here. Finally, we propose simple practical solutions leading to more peaceful interactions in groups of domestic horses, based on the knowledge of horses’ natural social life which therefore should be enhanced (e.g. ensuring roughage availability, favouring group stability, introducing socially experienced adults in groups of young horses, etc.). The state of the art indicates that many questions still need to be answered. Given the importance of the associated welfare issues and the consequences on the use of horses, further research is required, which could benefit horses… and humans.
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Normando, S., Meers, L., Samuels, W. E., Faustini, M., & Ödberg, F. O. (2011). Variables affecting the prevalence of behavioural problems in horses. Can riding style and other management factors be significant? Appl. Anim. Behav. Sci., 133(3-4), 186–198.
Abstract: The effects of riding style and various management factors on the prevalence of stereotypies and other behavioural problems among 346 mixed-breed saddle horses (phase 1) and 101 Arabian horses (phase 2) were analysed through a questionnaire answered by owners. In phase 1, the questionnaire data were partially validated through 20-min observations of 81 (23.3%) of the cases. Results indicate that horses primarily ridden in the English style were reported to be significantly more likely to display stereotypies (p < 0.001), problems when transported (p = 0.001), multiple behavioural problems (p < 0.001), and to have more restrictive stabling (p < 0.001) than horses ridden with other styles. When only Arabian horses were assessed in phase 2, however, there was no significant difference in behavioural problems between the Arabian horses ridden English style versus other riding styles. However Arabian horses were housed less restrictively than horses in phase 1 and English riding style and restrictive stabling tended to exacerbate each other's association with stereotypies. Management-related effects were found when, e.g., horses housed in restrictive stabling were more frequently reported to show locomotion stereotypies (p = 0.02) and those denied ad libitum hay displayed stereotypic wood-chewing behaviour (p = 0.02). To aid diagnosing and prioritizing interventions and care, the most predictive subsets of factors were computed for the various problem behaviours. E.g., among saddle horses, a statistical model comprised of the main riding style, duration of access to a paddock, and horse's age predicted whether a horse was reported to display any behavioural problem 62% of the time. This study supports the effects of management and handling on the prevalence of behavioural problems, and helps prioritize the relative importance of broad management categories on equine welfare. In particular, it underscores the importance of riding style on the well-being of saddle horses.
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Christensen, J. W., Søndergaard, E., Thodberg, K., & Halekoh, U. (2011). Effects of repeated regrouping on horse behaviour and injuries. Appl. Anim. Behav. Sci., 133(3), 199–206.
Abstract: Domestic horses are faced with social challenges throughout their lives due to limitations in social contact, space restrictions and frequent changes in social companionship. This is in contrast to natural conditions where horses live in relatively stable harem bands. Currently, little is known about how repeated regrouping affect horse behaviour and welfare, and it is unknown whether horses may adapt to regrouping. In this study, we aimed to investigate the effects of an unstable group structure, caused by weekly regroupings, on behaviour and frequency of injuries in young horses. Forty-five horses were included in the study and were randomly assigned to the treatments; Stable (S; seven groups of three horses) or Unstable (U; eight groups of three horses). The experimental period lasted 7 weeks, during which horses in Stable groups remained in the same group, whereas one horse was exchanged between Unstable groups every week. The groups were kept in 80m×80m grass-covered enclosures and were fed additional roughage on the ground daily. Social interactions were recorded in Unstable groups immediately after each regrouping (30min), and in both Stable and Unstable groups on day 1, 3 and 6 after each regrouping (2×20min/group/day). Injuries were scored by the end of the experimental period. The level of aggression shown by horses in Unstable groups immediately after regrouping was not affected by week (F5,35=0.42, P=0.83), indicating that horses neither habituated, nor sensitized, to repeated regrouping. Compared to horses in Stable groups, more agonistic behaviour was shown by horses in Unstable groups (i.e. non-contact agonistic; F1,65=5.60, P=0.02), whereas there was no treatment effect on other variables. The level of play behaviour appeared, however, to be more variable in Unstable groups. There was a significant effect of week on the level of contact agonistic interactions as well as greeting behaviour, due to a high occurrence in weeks 4-6. Non-contact agonistic interactions constituted the major part of agonistic interactions (66%). Possibly as consequence, no serious injuries were registered and there was no treatment effect (U=184; P=0.11). We conclude that the behaviour of young horses is affected by group management, and that horses appear not to adapt to weekly regroupings.
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