Abstract: A human-animal relationship can be developed through subsequent interactions, affected by the positive or negative emotional valence of the proceeding one. Horses implement a process of categorization to classify humans with whom they interact as positive, negative, or neutral stimuli by evaluating the kind of approach and the nature of the contact. In these terms, human-animal interactions are emotionally charged events, eliciting specific emotional states in both subjects involved. Although the human-horse relationship has been mainly investigated through behavioral analysis, physiological indicators are needed for a more objective assessment of the emotional responses. Heart rate variability (HRV) is a commonly used autonomic nervous system (ANS) correlate estimating the sympathovagal balance as a psychophysiological marker of emotion regulation in horses. We have assumed that long-term positive relationships with humans may have a positive and immediate impact on the emotional arousal of the horse, detectable, via ANS activity, during the interaction. We analyzed horses' heartbeat dynamics during their interaction with either familiar or unfamiliar handlers, applying a standardized experimental protocol consisting of three different conditions shifting from the absence of interaction to physical contact. The ANS signals were monitored through an innovative non-invasive wearable system, not interfering with the unconscious emotional response of the animal. We demonstrated that horses appeared to feel more relaxed while physically interacting (e.g., grooming on the right side) with some familiar handlers compared to the same task performed by someone unfamiliar. The shift of the sympathovagal balance toward a vagal predominance suggests that the horses experienced a decrease in stress response as a function not only of the handler's familiarity but also of the type of interaction they are experiencing. These results constitute the objective evidence of horses' capacity to individually recognize a familiar person, adding the crucial role of familiarity with the handler as a paramount component of human-animal interaction. Our rigorous methodological approach may provide a significant contribution to various fields such as animal welfare while further investigating the emotional side of the human-animal relationships.

Abstract: This paper describes how man can enter the social hierarchy of the horse by mimicking the behaviour and stance it uses to establish dominance. A herd is organised according to a dominance hierarchy established by means of ritualised conflict. Dominance relationships are formed through these confrontations: one horse gains the dominant role and others identify themselves as subordinates. This study was conducted using five females of the Haflinger breed, totally unaccustomed to human contact, from a free-range breeding farm. The study methods were based on the three elements fundamental to the equilibrium of the herd: flight, herd instinct and hierarchy. The trainer-horse relationship was established in three phases: retreat, approach and association. At the end of the training sessions, all of the horses were able to respond correctly to the trainer. These observations suggest that it is possible to manage unhandled horses without coercion by mimicking their behaviour patterns.

Abstract: This article focuses on the validation of smart textile electrodes used to acquire electrocardiogram (ECG) signals in horses in a comfortable and robust manner. The performance of smart textile electrodes is compared with standard Ag/AgCl electrodes in terms of the percentage of motion artifacts (MAs, the noise that results from the movement of electrodes against the skin) and signal quality. Seven healthy Standardbred mares were equipped with 2 identical electronic systems for the simultaneous collection of ECGs. One system was equipped with smart textile electrodes, whereas the second was equipped with standard Ag/AgCl electrodes. Each horse was then monitored individually in a stall for 1 hour, without any movement constraints. The ECGs were visually examined by an expert who blindly labeled the ECG segments that had been corrupted by MAs. Finally, the percentage of MAs (MA%) was computed as the number of samples of the corrupted segments over the whole length of the signal. The total MA% was found to be lower for the smart textiles than for the Ag/AgCl electrodes. Consistent results were also obtained by investigating MAs over time. These results suggest that smart textile electrodes are more reliable when recording artifact-free ECGs in horses at rest. Thus, improving the acquisition of important physiological information related to the activity of the autonomic nervous system, such as heart rate variability, could help to provide reliable information on the mood and state of arousal of horses.

Abstract: The objective of this study was to investigate the ability of horses (Equus caballus) to detour around symmetric and asymmetric obstacles. Ten female Italian saddle horses were each used in three detour tasks. In the first task, the ability to detour around a symmetrical obstacle was evaluated; in the second and third tasks subjects were required to perform a detour around an asymmetrical obstacle with two different degrees of asymmetry. The direction chosen to move around the obstacle and time required to make the detour were recorded. The results suggest that horses have the spatial abilities required to perform detour tasks with both symmetric and asymmetric obstacles. The strategy used to perform the task varied between subjects. For five horses, lateralized behaviour was observed when detouring the obstacle; this was consistently in one direction (three on the left and two on the right). For these horses, no evidence of spatial learning or reasoning was found. The other five horses did not solve this task in a lateralized manner, and a trend towards decreasing lateralization was observed as asymmetry, and hence task difficulty, increased. These non-lateralized horses may have higher spatial reasoning abilities.

Abstract: Recent studies have tested the ability of horses to understand human gestures. But even at the moment results are rather contradictory. This study was aimed at analyzing ability of horses to understand, remember and use human-given cues in a delayed three choice task. After the training period, sixteen horses had to choose between three blue buckets. One of them hid a carrot. Eight horses (A-group) saw the person hiding the carrot and they had to choose the correct bucket only after the person had hidden carrot and gone away. Control group, eight horses (B-group) did not know where the carrot was, and could only choose the bucket through the use of smell or by random choice. Each horse carried out 10 trials in the same test session. A-group chose the correct bucket to a greater extent on the first try (4.37±1.42), compared to the second (3.00±0.53) and the third try (0.75±0.71). With significant differences between the first and the second try (t14=2.582, p=0.022), the first and the third try (t14=6.508, p=0.000), and between the second and the third try (t14=7.180, p=0.000). Also the B-group chose the correct bucket to a greater extent on the first try (3.87±0.83) compared to the second (3.37±1.51) and the third (1.75±1.49). Anyway, there was no differences between the first and the second try (t14=0.821, p=0.425). As regards the B-group, statistical differences were found between the first and the third try (t14=3.523, p=0.003) and between the second and the third try (t14=2.171, p=0.048). Moreover, A-group showed a negative correlation (r=-0.652, p=0.0409) between the number of correct answers at first trial, and seemed that they used human information during the first half of the trials. As the trials proceeded, the average time required to find carrot decreased, with a negative correlation (r=-0.779, p=0.0079) over trials while, the number of overturned bucket to find carrot increased over trials (r=0.770, p=0.0091). As the trials proceeded, the horses tended to choose at first the bucket where the carrot had been found in the previous trial (r=0.450, p=0.013). Any kind of correlation over trials was found in B-group. In the first trials, the horses we studied seemed to understand human given-cues information, store it and use it appropriately even in absence of a person. As trials proceeded they seemed to change strategy, searching carrots where it had been found in the previous trial. Therefore, horses could use human given-cues or other cognitive strategy depending on the time, energy cost and mental effort required to solve the task. KW -