Abstract: Here we provide confirmation that the 'ramp retina' of the horse, once thought to result in head rotating visual behaviour, does not exist. We found a 9% variation in axial length of the eye between the streak region and the dorsal periphery. However, the difference was in the opposite direction to that proposed for the 'ramp retina'. Furthermore, acuity in the narrow, intense visual streak in the inferior retina is 16.5 cycles per degree compared with 2.7 cycles per degree in the periphery. Therefore, it is improbable that the horse rotates its head to focus onto the peripheral retina. Rather, the horse rotates the nose up high to observe distant objects because binocular overlap is oriented down the nose, with a blind area directly in front of the forehead.

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.

Abstract: Horses constantly modify their behaviour as a result of experience. This involves the creation of an association between events or stimuli. The influence of people on the modification and generation of certain behaviour patterns extends beyond the intentional training of the horse. The impact of any action depends on how it is perceived by the horse, rather than the motive of the handler. Negative and positive reinforcement increase the probability of specific behaviours recurring i.e. strengthen the association between events, whereas punishment reduces the probable recurrence of a behaviour without providing specific information about the desired alternative. In this paper the term 'punishers' is used to refer to the physical aids, such as a whip or crop, which may be used to bring about the process of punishment. However, if their application ceases when a specific behaviour occurs they may negatively reinforce that action. Intended 'punishers' may also be rewarding (e.g. for attention seeking behaviour). Therefore, contingency factors (which define the relationship between stimuli, such as the level of reinforcement), contiguity factors (which describe the proximity of events in space or time) and choice of reinforcing stimuli are critical in determining the rate of learning. The many problems associated with the application of punishment in practice lead to confusion by both horse and handler and, possibly, abuse of the former. Most behaviour problems relate to handling and management of the horse and can be avoided or treated with a proper analysis of the factors influencing the behaviour.

Abstract: Horses kept in stalls are deprived of opportunities for social interactions, and the performance of natural behaviors is limited. Inadequate environmental conditions may compromise behavioral development. Initial training is a complex process and it is likely that the responses of horses may be affected by housing conditions. Sixteen 2-year-old Arabian horses were kept on pasture (P) (n=8) or in individual stalls (S) (n=8). Twelve horses (six P and six S) were subjected to a standardized training procedure, carried out by two trainers in a round pen, and 4 horses (two P and two S) were introduced to the round pen but were not trained (C; control). On sample collection day 0, 7, 21 and 28, behavior observations were carried out, blood samples were drawn and heart rates were monitored. Total training time for the stalled horses was significantly higher than total time for the pastured horses (S: 26.4+/-1.5 min; P: 19.7+/-1.1; P=0.032). The stalled group required more time to habituate to the activities occurring from the start of training to mounting (S: 11.4+/-0.96; P: 7.3+/-0.75 min; P=0.007). Frequency of unwanted behavior was higher in the stalled horses (S: 8.0+/-2.0; P: 2.2+/-1.0; P=0.020). Pastured horses tended to have higher basal heart rates on day 0 (S: 74.7+/-4.8; P: 81.8+/-5.3 bpm; P=0.0771). While the physiological data failed to identify differences between housing groups, the behavioral data suggest that pasture-kept horses adapt more easily to training than stalled horses.

Abstract: Human relationships or interactions with horses have varied throughout history depending on human needs, but it is horses' ability to carry a human individual that has had perhaps the greatest impact on their relationship with man. Despite our long association with the horse, there have been few studies on human-horse relationships. There is little historical evidence on individual relationships with horses but indications of strong human-horse relationships have been noted in mounted societies, such as North American Plains Indians. Riding a horse has traditionally been associated with power, and was reserved for the ruling elite in many areas. Demographic data suggest that human relationships with horses may have changed in recent times. Although the lack of land and the relatively high cost of horse care may reduce the possibility of ownership for many people, the availability of riding establishments and increases in leisure time mean that riding is no longer restricted to the upper classes. There is a wide range in type and intensity of potential interactions with horses, indicating that human-horse relationships are likely to vary considerably. Some people appear to sacrifice a great deal in order to own a horse. However, the motivation behind these activities and the process by which an individual assesses personal costs of ownership versus their perceived benefits remains to be studied. Future research should focus on characterising the human-horse relationship, and the degree of individual and cultural variation. A greater understanding of horse owner perceptions of 'costs' versus 'benefits' may also increase our understanding of the relationship and the economic importance of horses in society.