Social relationships in a herd of Sorraia horses

Proximity tracking using ultra-wideband technology for equine social behaviour research

Sociopositive interactions with conspecifics are essential for equine welfare and quality of life. This study aimed to validate the use of wearable ultra-wideband (UWB) technology to quantify the spatial relationships and dynamics of social behaviour in horses by continuous (1/s) measurement of interindividual distances. After testing the UWB devices' spatiotemporal accuracy in a static environment, the UWB measurement validity, feasibility and utility under dynamic field conditions was assessed in a group of 8 horses. Comparison of the proximity measurements with video surveillance data established the measurement accuracy and validity (r = 0.83, p < 0.0001) of the UWB technology. The utility for social behaviour research was demonstrated by the excellent accordance of affiliative relationships (preferred partners) identified using UWB with video observations. The horses remained a median of 5.82 m (95% CI 5.13-6.41 m) apart from each other and spent 20% (median, 95% CI 14-26%) of their time in a distance ≤ 3 m to their preferred partner. The proximity measurements and corresponding speed calculation allowed the identification of affiliative versus agonistic approaches based on differences in the approach speed and the distance and duration of the resulting proximity. Affiliative approaches were statistically significantly slower (median: 1.57 km/h, 95% CI 1.26-1.92 km/h, p = 0.0394) and resulted in greater proximity (median: 36.75 cm, 95% CI 19.5-62 cm, p = 0.0003) to the approached horse than agonistic approaches (median: 3.04 km/h, 95% CI 2.16-3.74 km/h, median proximity: 243 cm, 95% CI 130-319 cm), which caused an immediate retreat of the approached horse at a significantly greater speed (median: 3.77 km/h, 95% CI 3.52-5.85 km/h, p < 0.0001) than the approach.

Video Ethogram of Equine Social Behaviour

Equine social behaviour studies face challenges stemming from the absence of a comprehensive ethogram with unequivocal standardised definitions and the resulting limits to data comparison across studies. To address these constraints, this ethogram offers researchers a standardised framework, defining thirty-seven distinct equine social behaviours supplemented by video examples for enhanced clarity. These definitions amalgamate insights from existing ethograms and are fine-tuned through meticulous video observations, encompassing contextual cues such as distinguishing between aggressive and playful circling based on ear position and facial expressions and communicative nuances to provide a detailed representation of equine social behaviours. Video recordings complement the standardised definitions by capturing the dynamic flow and sequence of social interactions. By providing a dynamic and detailed representation, videos allow researchers to observe the temporal aspects of behaviour, including the sequence, duration, and rhythm of interactions. These detailed data are crucial for interpreting social behaviours and unravelling the complexities of equine societies. Standardized and video-illustrated definitions of equine social behaviour facilitate clear and consistent communication between researchers, enabling cross-study comparisons regarding the impact of husbandry practices and health conditions on equine social behaviour, which, in turn, can facilitate the assessment and optimisation of management practices and equine welfare.

Social networks of reintroduced Przewalski's horses in the Great Gobi B Strictly Protected Area (Mongolia)

Analyzing social networks is a powerful tool for understanding the ecology of social species. While most studies focus on the role of each group member, few compare groups with different characteristics. The current population of Przewalski's horses Equus ferus przewalskii at the Great Gobi B Strictly Protected Area (Mongolia) includes groups of wild-born and captive-bred individuals with different experiences with the area (acclimatizing, long-term reintroduced, and wild-born), therefore serving as an ideal natural behavioral lab. We filmed 11 groups for 141.5 hours in summer 2018 (July), late spring 2019 (May, June), and autumn 2019 (September, October). Affiliative and agonistic interactions were recorded, and social networks were created. We tested the influence of origin, experience, season, sex, age, relative time belonging to the group, relatedness, and dominance rank on different network indices at the individual and group levels. We found that groups with greater experience in the area are generally better connected than members of the newly formed groups. However, these strong networks were created by wild-born individuals with very low interaction rates. On the contrary, inexperienced groups composed of captive-bred individuals displayed many interactions but created weak social networks. The results show a trend of behavioral transition from acclimatizing through long-term reintroduced to wild-born groups, supporting that the newly formed groups of released Przewalski's horses need time to display the typical social behavior patterns of wild-born individuals. Long-term monitoring of released Przewalski's horses is recommended to promote the success of this reintroduction program.

Reported Agonistic Behaviours in Domestic Horses Cluster According to Context

Agonistic behaviours are often directed at other animals for self-defence or to increase distance from valued resources, such as food. Examples include aggression and counter-predator behaviours. Contemporary diets may boost the value of food as a resource and create unanticipated associations with the humans who deliver it. At the same time the domestic horse is asked to carry the weight of riders and perform manoeuvres that, ethologically, are out-of-context and may be associated with instances of pain, confusion, or fear. Agonistic responses can endanger personnel and conspecifics. They are traditionally grouped along with so-called vices as being undesirable and worthy of punishment; a response that can often make horses more dangerous. The current study used data from the validated online Equine Behavioural and Research Questionnaire (E-BARQ) to explore the agonistic behaviours (as reported by the owners) of 2734 horses. With a focus on ridden horses, the behaviours of interest in the current study ranged from biting and bite threats and kicking and kick threats to tail swishing as an accompaniment to signs of escalating irritation when horses are approached, prepared for ridden work, ridden, and hosed down (e.g., after work). Analysis of the responses according to the context in which they arise included a dendrographic analysis that identified five clusters of agonistic behaviours among certain groups of horses and a principal component analysis that revealed six components, strongly related to the five clusters. Taken together, these results highlight the prospect that the motivation to show these responses differs with context. The clusters with common characteristics were those observed in the context of: locomotion under saddle; saddling; reactions in a familiar environment, inter-specific threats, and intra-specific threats. These findings highlight the potential roles of fear and pain in such unwelcome responses and challenge the simplistic view that the problems lie with the nature of the horses themselves rather than historic or current management practices. Improved understanding of agonistic responses in horses will reduce the inclination of owners to label horses that show such context-specific responses as being generally aggressive.

Age-specific effects of density and weather on body condition and birth rates in a large herbivore, the Przewalski's horse

Reproduction in young females can show a particularly sensitive response to environmental challenges, although empirical support from individual-based long-term studies is scarce. Based on a 20-year data set from a free-roaming Przewalski's horse population (Equus ferus przewalskii), we studied effects of large-herbivore density (horses + cattle) and weather conditions experienced during different life stages on females' annual birth rates. Foaling probability was very low in 2-year-olds, reaching maximum values in 5 to 10-year-olds, followed by a decrease in older females indicating reproductive senescence. Mother's previous reproductive investment affected her current reproduction; young and old mothers (as opposed to middle-aged ones), which had nursed a foal for at least 60 days during the previous year, reproduced with a lower probability. Foaling probability and body condition of young females were lower when large-herbivore density was high. Reproduction was also influenced by interactive weather effects during different life stages. Low late-summer precipitation during the females' year of birth was associated with a pronounced decrease in foaling probability in response to harsh late-winter temperatures prior to the mating season. In turn, increased amounts of late-summer rain during this early age together with more late-summer rain during the females' current pregnancy led to an increased reproductive probability in 2-3-year-olds. These results were corroborated by the ameliorating effects of late-summer rain on body condition in such females. In conclusion, our findings highlight the interactive importance of weather conditions experienced during early life, and of density and weather during current pregnancy on foaling probability, particularly in young females.

Equine Social Behaviour: Love, War and Tolerance

Sociality is an ethological need of horses that remained unchanged by domestication. Accordingly, it is essential to include horses' social behavioural requirements and the opportunity to establish stable affiliative bonds in equine management systems and welfare assessment. Thus, this systematic review aims to provide an up-to-date analysis of equine intraspecific social ethograms. A literature review yielded 27 papers that met the inclusion criteria by studying adult (≥2 years) equine social behaviour with conspecifics using a well-defined ethogram. Social interactions were observed in 851 horses: 320 (semi-)feral free-ranging, 62 enclosed (semi-)feral and 469 domesticated, living in groups averaging 9.1 (mean +/- 6.8 s.d., range: 2-33) horses. The ethograms detailed in these 27 studies included a total of 40 (mean: 12.8/paper, range: 2-23) social behaviours, of which 60% (24/40) were agonistic, 30% (12/40) affiliative, 7.5% (3/40) investigative and 2.5% (1/40) neutral. The 27 publications included 67.7% agonistic and only 26% affiliative, 5.1% investigative and 1.2% neutral social behaviours in their methodology, thus focusing predominantly on socio-negative interactions. The strong emphasis on agonistic behaviours in equine ethology starkly contrasts with the rare occurrence of agonistic behaviours in stable horse groups and the well-established importance of affiliative interactions for equine welfare. The nuanced and complex equine social behaviour requires refinement of the ethogram with a greater focus on affiliative, ambivalent and indifferent interactions and the role of social tolerance in equine social networks to advance equine welfare assessment.

Show me your best side: Lateralization of social and resting behaviors in feral horses

Growing evidence shows a variety of sensorial and motor asymmetries in social and non-social interactions in various species, indicating a lateralized processing of information by the brain. Using digital video cameras on tripods and drones, this study investigated lateralization in frequency and duration of social behavior patterns, in affiliative, agonistic, and resting contexts, in a feral population of horses (Equus ferus caballus) in Northern Portugal, consisting of 37 individuals organized in eight harem groups. Affiliative interactions (including grooming) were more often performed, and lasted longer, when recipients were positioned to the right side. In recumbent resting (animals lying down) episodes on the left side lasted longer. Our results of an affiliative behavior having a right side tendency, provide partial support to the valence-specific hypothesis of Ahern and Schwartz (1979) - left hemisphere dominance for positive affect, affiliative behaviors. Longer recumbent resting episodes on the left side may be due to synchronization. However, in both instances it is discussed how lateralization may be context dependent. Investigating the position asymmetries of social behaviors in feral equids will contribute to a better understanding of differential lateralization and hemispheric specialization from the ecological and evolutionary perspectives.

Tend and Befriend in Horses: Partner Preferences, Lateralization, and Contextualization of Allogrooming in Two Socially Stable Herds of Quarter Horse Mares

Studies show that horses express favoritism through shared proximity and time and demonstrate unique affiliative behaviors such as allogrooming (mutual scratching) with favorite conspecifics. Allogrooming also occurs more frequently during stress and has been observed to occur more frequently in domestic herds than feral. The role of partner preference, lateralization, and duration of allogrooming as measures of social bonding has remained unclear. The present study looked at two socially stable herds of mares (n = 85, n = 115) to determine the frequency, duration, visual field of view and partner preference during allogrooming in both pasture settings (low stress) and confined settings (higher stress). One hundred and fifty-three videos for both herds were coded for allogrooming behaviors with 6.86 h recorded in confined conditions and 31.9 h in pasture settings. Six allogrooming sessions were observed in the pasture setting with an average duration of 163.11 s. In confined settings, a total of 118 allogrooming sessions were observed with an average duration of 40.98 s. Significant (p < 0.01) differences were found between settings for duration (s), number of allogrooming pairs, and frequency of allogrooming (per min) for each herd. All observed allogrooming sessions involved pairs of favored conspecifics (one partner per horse). The current study suggests that horses may have friendships that can be observed through the demonstration of specific affiliative behaviors during times of stress with more frequent, but shorter affiliative interactions with preferred partners during times of stress. This context suggests that horses adhere to the “tend and befriend” principles of friendship in animals.

The behavior of horses stabled in a large group at essential resources (watering point and lying halls)

Since there is a practical need, this study focused on the behavior of 51 horses kept in one large group in order to make management suggestions regarding the animal:watering point ratio and the design of lying halls. Drinking events and interactions between pairs of horses were analyzed for 18 days as well as the occupancy time of the watering point. The time period, had significant effects on drinking events with visible interactions (P < 0.05). The highest least square means (LSM) and standard errors (SE) of drinking events with and without visible interaction were observed between 12 noon-2 p.m. (8.6 ± 1.6 and 13.6 ± 2.2 drinking events, respectively) which was also the time period of main occupancy of the watering point (41.9 ± 2.7 min/2h). About 57% of drinking events were classed as with visible interaction, of which over 90% were mild (i.e. laying back of ears, tightening of face). Horses' behavior (resting while standing/others) and lying positions (sternal/lateral) in different lying halls were analyzed over 36 days by generalized mixed models. The sternal position was preferred (12.4 ± 1.4 - 39.2 ± 3.0%) compared to the lateral one (1.4 ± 0.4% - 8.3 ± 1.6%). Older horses spent significantly less time in the sternal position (13.8 ± 1.6%) and rested more standing (45.4 ± 3.3%) compared to younger horses (26.4 ± 4.5% and 29.1 ± 4.9%, respectively) (P < 0.05). Overall, this study provides first insights into drinking and lying behavior of horses kept in a large group.

Behavioural and Physiological Changes in a Herd of Arabian Mares after the Separation of Individuals Differently Ranked within the Dominance Hierarchy

Simple Summary

There are many situations in riding facilities and studs in which horses have to be separated out of a group, for example, when they are needed for a riding lesson, training purposes or veterinary treatments. Such a group may form a social herd in which a dominance hierarchy with dominant and submissive members is established. In the study, we investigated how mares respond to a short separation of some of the herd members and whether the response differs according to the rank order of the mares separated. The response was determined with rates of different behaviours showing agitation or calmness, times of locomotion and physiological parameters. The results of the experiment show that the separation of some mares increases the agitation in the remaining herd. In spite of the fact that such situations are constantly repeated in practice, they are stressful for the horses. The reaction of the remaining herd does not depend strictly on the composition of the mares separated regarding their rank in the dominance hierarchy, i.e., it does not differ consistently when a dominant, mixed or submissive group of mares is separated.

Abstract

Horses in a herd develop and maintain a dominance hierarchy between all individuals. There are many situations in riding facilities and studs in which horses have to be separated out of a group. The aim of the study was to determine the rate of behaviours, level of locomotor activity and cardiac activity variables in a herd of horses during a short social separation of individuals differently ranked in the dominance hierarchy. Twelve adult Arabian mares were involved. A behavioural test had been performed before the main experiment to determine the rank order of the mares in this social herd. Three tests were performed when a dominant, mixed and submissive three-member group of mares was separated for 10 min. The response of the remaining herd was determined by a rate of behaviours, time of locomotor activity and cardiac parameters. The results of the experiment reveal evident changes towards emotional arousal in the social herd elicited by a short separation of some conspecifics. The herd created by humans preserves the sensitivity to a temporary loss of its members. The response of the remaining herd does not depend strictly on the composition of the separated mares regarding their rank in the dominance hierarchy.

Dominance and Leadership in the Equine Social Structure: A Preliminary Study About Mules and Sex Influence

Little is known about the dominance and leadership behaviors in the social structure of mules (Equus caballus × Equus asinus). Based on the frequency of threat and aggressive behaviors, we compared the social structure, dominance, and leadership of independent groups of mules and horses (n = 11 per group), and filmed the frequency of these behaviors over a period of four days. In both groups, aggressions were uncommon and, when based on threats, the social structure was linear and consistent with males ranking higher in dominance. When compared to horses, mules exhibited some agonistic social interactions without a recognized submissive individual and displayed more specific aggressive behaviors, whereas horses presented more specific threat behaviors. Comparing between groups, mares exhibited more leader behaviors than female mules, in contrast to male horses which showed fewer leader behaviors than male mules. Regarding behaviors within the mule group, males showed more leader and threat behaviors than females, while females showed more frequent aggression. While in horses, the females showed more leader behaviors than male horses and, although there were differences in specific agonistic behaviors, both sexes presented more often threat behaviors. In this preliminary study, we conclude that the social structure of mules, although similar to those of horses, showed to be less stable, since it involves more aggression and agonistic social interactions without a submissive. Moreover, although mules did not present a sex influence on leadership as horses did, they presented it on aggression: females showed more aggression than males.

Two Hours of Separation Prior to Milking: Is This Strategy Stressful for Jennies and Their Foals?

Simple Summary

The economic importance of donkeys has decreased in Brazil, which has led to their mass abandonment. Asinine milk production is a potential solution to the reintroduction of donkeys into the Brazilian social and economic scenario. The milk has nutraceutical properties that make it valuable for human consumption, and thus a donkey dairy industry is likely to help stop their abandonment. That said, in any such industry, the welfare of jennies maintained for milk production must be guaranteed. Few studies have been published measuring the impact of milking management on the welfare of jennies and foals, and the potential behavioural and physiological challenges it may cause. It is also unknown whether these animals adapt to the milking routine. The goal of this study was to assess the impact of separating Pêga jennies from their foals for 2 h on indicators of welfare. Animal welfare was analysed through behavioural and hormonal assessments, their potential adaptive responses and effects on milk yield. Few significant alterations were found in behaviour, salivary cortisol concentrations, or milk yield as a result of the 2-h separation, which could indicate that the welfare of the animals was not compromised; however, the adaptation of jennies and foals to separation stress remains to be fully verified. The 2-h separation period, based on the reported data, is possibly not a stressful experience for the assessed group of Pêga jennies and foals. The reported protocol, which included frequent positive interactions with the animals, may be useful to assure acceptable animal welfare levels for donkeys in small-scale dairy production settings.

Abstract

The goal of this study was to assess whether or not a separation period of 2 h is stressful for jennies and foals, as measured by changes in behaviour, salivary cortisol, and milk production. This study was reviewed and approved by the Committee for the Use and Care of Animals in Research (CEUA) of the School of Veterinary Medicine and Animal Science of the University of São Paulo. Fourteen multiparous Pêga jennies (245 kg average body weight) and their foals were assessed from day 45 to 135 of lactation. Dams and foals were separated for 2 h prior to milking. Behavioural assessments and saliva samples were collected before and after separation, every 15 days, resulting in 14 samples per individual animal. Behavioural states (affiliative and inactivity) and events (agonistic, abnormal, eliminative and vocalisations) of the jennies were observed during 6 min in both periods. Moreover, milk yield was measured. Few significant behavioural and salivary cortisol changes were observed, and milk yield was not affected by cortisol levels in response to the separation. The 2-h separation period, on the basis of the collected variables, did not appear to be stressful for the assessed group of Pêga jennies or foals; however, their ability to adapt to milking routine stress remains to be investigated.

The Contribution of Mutual Grooming to Affiliative Relationships in a Feral Misaki Horse Herd

Simple Summary

Social grooming strengthens affiliative relationships between participants in many social primates. Three hypotheses regarding the function of mutual grooming in feral horses were tested: the affiliative relationship strengthening hypothesis, the worsened relationship restoring hypothesis, and the parasite removal hypothesis. All the nine horses in the “6m” herd in a Misaki feral horse (Equus caballus) herd in Cape Toi, Japan, were investigated in terms of kinship, grooming, aggression, proximity, social rank, and social network. The correlations between mutual grooming and proximity and between aggression and proximity were established mathematically. Controlling for kinship, there were significant positive partial correlations between mutual grooming and proximity and between aggression and proximity. No correlation was observed between aggression and mutual grooming. Individuals that spent less time on self-grooming invested longer times receiving grooming from other individuals. In a feral horse population, mutual grooming maintains hygiene by controlling ectoparasites and forges affiliative interactions between herd members.

Abstract

Although herd size, structure, stability, and social rank among Misaki feral horses have been reported, no studies have been conducted on the affiliative relationships and interactions among members in a Misaki horse herd. The validity of three hypotheses regarding the function of social grooming, the affiliative relationship strengthening hypothesis, the worsened relationship restoring hypothesis, and the grooming parasite removal hypothesis, were tested in a Misaki feral horse (Equus caballus) herd in Cape Toi, Japan. All the nine horses in the “6m” herd were investigated in terms of kinship, grooming, aggression, proximity, social rank, and social network. Mutual grooming occurred only in pairs and was almost perfectly symmetrical. For each member, there was a significant negative correlation between total grooming received from other individuals and self-grooming. Controlling for kinship, there were significant positive partial correlations between mutual grooming and proximity and between aggression and proximity. No correlation was observed between aggression and mutual grooming. The results suggest that mutual grooming symmetry may contribute that both participants simultaneously benefit from parasite removal and strengthen affiliative relationships between seasonally changing herd members; however, mutual grooming did not foster restoring the worsened relationship following aggression promoted by physical proximity. The findings of this study may elucidate the mechanisms by which interactions between herd members are maintained or strengthened.

Domesticated horses differ in their behavioural and physiological responses to isolated and group housing

The predominant housing system used for domestic horses is individual stabling; however, housing that limits social interaction and requires the horse to live in semi-isolation has been reported to be a concern for equine welfare. The aim of the current study was to compare behavioural and physiological responses of domestic horses in different types of housing design that provided varying levels of social contact. Horses (n = 16) were divided equally into four groups and exposed to each of four housing treatments for a period of five days per treatment in a randomized block design. The four housing treatments used were single housed no physical contact (SHNC), single housed semi-contact (SHSC), paired housed full contact (PHFC) and group housed full contact (GHFC). During each housing treatment, adrenal activity was recorded using non-invasive faecal corticosterone metabolite analysis (fGC). Thermal images of the eye were captured and eye temperature was assessed as a non-invasive measure of the stress response. Behavioural analysis of time budget was carried out and an ease of handling score was assigned to each horse in each treatment using video footage. SHNC horses had significantly higher (p = 0.01) concentrations of fGC and were significantly (p = 0.003) more difficult to handle compared to the other housing types. GHFC horses, although not significantly different, had numerically lower concentrations of fGC and were more compliant to handling when compared to all other housing treatments. Eye temperature was significantly (p = 0.0001) lower in the group housed treatment when compared to all other treatments. These results indicate that based on physiological and behavioural measures incorporating social contact into the housing design of domestic horses could improve the standard of domestic equine welfare.

Age and group residence but not maternal dominance affect dominance rank in young domestic horses

We present a study focused on those factors influencing dominance position in young horses, with emphasis on the role of the mother. Horses, as other group-living polygynous mammals, form stable linear dominance hierarchies based on agonistic interactions. Higher dominance positions are believed to be connected, in both sexes, to better condition and higher reproductive success. Many variables play a role in forming the dominant-submissive relationships between horses; however, the maternal effect on the dominance position of the offspring still remains unclear, as do the possible mechanisms of transference ("inheritance"). We hypothesized that the maternal dominance position, plus differences in suckling parameters or maternal style, may be responsible for later outcome of the offspring's dominance position, characterized by 2 variables: index of fighting success (CB); and rate of winning encounters (RW). Our study animals were 8 groups of Kladruby horses, loose-housed lactating mares with foals (n = 66 mare-foal pairs); and subsequently 4 groups of the same foals at 3 yr of age. Our results revealed the impact of age on the dominance position of the young horses (P < 0.001 for CB, and P < 0.01 for RW), and residence in the group (P < 0.01, P < 0.01, respectively); not the maternal dominance position. Older foals reached higher dominance positions, independent of the dominance position, age, or experience of the mother; therefore, we did not find support for direct inheritance of maternal rank. Nevertheless, the foals born to the same mare in 2 consecutive seasons (n = 16 mares) revealed fair repeatability in the dominance position they obtained at 3 yr of age (intraclass correlation coefficient = 0.46). This suggests an important constant effect of the mother on the social success of her progeny; however, we did not find a significant effect of any of the tested variables describing maternal characteristics or maternal care. Dominance position depended significantly on the foal's age at observation, and the residence in the herd formed via sequential introducing of later-weaned groups of foals. The most dominant horses were mainly recruited from the first-weaned group of the season, and thus were also the oldest individuals in the herd. Further research is needed to discover the role of foal personality and mare style, and their links to possible dominance behaviors in a herd.

The role of an alpha animal in changing environmental conditions

The maintenance and development of conservation areas by grazing of large herbivores, such as Przewalski's horses, is common practice. Several nature conservation areas house male bachelor groups of this species. When males are needed for breeding they are removed from the groups, often without considering group compositions and individual social positions. However, alpha animals are needed for ensuring group stability and decision making in potentially dangerous situations in several species. To investigate the role of the alpha male in a bachelor group, we observed the behaviour of five Przewalski's horse males during the enlargement of their enclosure. We analyzed the group's social structure and movement orders, as well as the animals' connectedness, activity budgets, and whether they moved with preferred group members and how factors such as social rank influenced the horses' behaviour. We also investigated the excretion of glucocorticoid metabolites (GCM) via faeces of the horses while exploring a new area as a parameter of glucocorticoid production. Our results show that the alpha male is important for a bachelor group in changing environmental conditions. The alpha male had the highest level of connectedness within the group. When exploring the new environment, its position in the group changed from previously being the last to being the first. Furthermore the whole group behaviour changed when exploring the new area. The stallions showed reduced resting behavior, increased feeding and did not stay close to each other. We found that the excretion of glucocorticoid metabolites of most horses rose only marginally during the first days on the new area while only the alpha male showed a significant increased amount of glucocorticoid production during the first day of the enclosure enlargement.

Influence of emotional balance during a learning and recall test in horses (Equus caballus)

Modern day horse-human relationships entail different types of sport and riding activities, which all require learning. In evaluating the interaction between learning and emotions, studying normal coping strategies or adaptive responses to the surroundings is critical. 34 horses were involved in a cognitive test, in the absence of physical effort, to analyze performance, as well as physiological and behavioral responses related to learning, memorization and recall, associated to the capacity to reverse a learned model. Synthetic Equine Appeasing Pheromone (EAP) was used in 17 horses in order to modulate their emotional state and evaluate differences in cognitive-emotional response during cognitive effort in comparison to the control group (placebo group). Both groups showed statistically significant changes in heart rate during the test, indicating emotional and physio-cognitive activation. The EAP group produced fewer errors and made more correct choices, showing behaviors related to increased attention, with less influence from environmental stimuli. The capacity to learn to learn, as shown in the bibliography, allows animals to establish conceptual learning, when a normal or positive emotional state (in this case modulated by semiochemicals) is used to control limbic system activation and, consequently, decrease stressful/fearful reactions, resulting in better learning capacities during the cognitive test.

Post-conflict friendly reunion in a permanent group of horses (Equus caballus)

Gregarious animals living in permanent social groups experience intra-group competition. Conflicts over resources can escalate into costly aggression and, in some conditions, non-dispersive forms of conflict resolution may be favoured. Post-conflict friendly reunions, hence reconciliation, have been described in a variety of species. The aim of this study was to explore, for the first time, the occurrence of reconciliation in a group of domestic horses (Equus caballus) and learn more about strategies used to maintain group cohesion. The behaviour of seven horses living as permanent group in an enclosure for at least 2 years was observed by video for 108h from June to August 2007. We used a Post-Conflict/Matched Control method to assess the existence of reconciliation and third-party affiliation. Behaviours recorded Post-Conflict, or during Matched Control periods, were classified as affiliative based on previous descriptions of visual communication patterns in horses. The proportion of attracted pairs over total post-conflict situations was significantly greater than the proportion of dispersed pairs, both during dyadic interactions (p<0.001) and during triadic interactions (p=0.002). The results of the present study show that both dyadic reconciliation and third-party post-conflict affiliative interactions form important social mechanisms for managing post-conflict situations in horses.

Social feeding decisions in horses (Equus caballus)

Like many other herbivores, in a natural environment equids feed on rather evenly distributed resources. However, the vegetation in their vast habitats constantly changes. If food is plentiful only little competition occurs over food, and in non-competitive situations domestic horses tend to return to the same feeding site until it is overgrazed. In contrast, they compete over limited food for which the social status of the individuals appears to be important. Especially in ruminants several studies have proved an influence of social organisations, rank, sex and the depletion of feeding sites on the feeding behaviour of individuals. However, it is not yet understood whether and how social aspects affect horses' feeding decisions. Curiosity about the influence of social rank on the horses' feeding decisions between two, equally with high-quality surplus food-filled buckets placed in different social feeding conditions, led us to create the test below. The observer horses were alternately tested with a dominant and a subordinate demonstrator placed in one of the three different positions. We conclude that domestic horses use social cognition and strategic decision making in order to decide where to feed in a social feeding situation. When possible they tend to return to the same, continuously supplied feeding site and switch to an "avoidance tendency" in the presence of dominant horses or when another horse is already feeding there. Thus, the social rank and the position of conspecifics affect the feeding strategy of horses.