Abstract: For centuries, a goal of training in many equestrian disciplines has been to straighten the horse, which is considered a key element in achieving its responsiveness and suppleness. However, laterality is a naturally occurring phenomenon in horses and encompasses body asymmetry, motor laterality and sensory laterality. Furthermore, forcibly counterbalancing motor laterality has been considered a cause of psychological imbalance in humans. Perhaps asymmetry and laterality should rather be accepted, with a focus on training psychological and physical balance, coordination and equal strength on both sides instead of enforcing “straightness”. To explore this, we conducted a review of the literature on the function and causes of motor and sensory laterality in horses, especially in horses when trained on the ground or under a rider. The literature reveals that body asymmetry is innate but does not prevent the horse from performing at a high level under a rider. Motor laterality is equally distributed in feral horses, while in domestic horses, age, breed, training and carrying a rider may cause left leg preferences. Most horses initially observe novel persons and potentially threatening objects or situations with their left sensory organs. Pronounced preferences for the use of left sensory organs or limbs indicate that the horse is experiencing increased emotionality or stress, and long-term insufficiencies in welfare, housing or training may result in left shifts in motor and sensory laterality and pessimistic mentalities. Therefore, increasing laterality can be regarded as an indicator for insufficiencies in housing, handling and training. We propose that laterality be recognized as a welfare indicator and that straightening the horse should be achieved by conducting training focused on balance, coordination and equal strength on both sides.

Abstract: We tested the hypothesis that social defensive responses to the vocalisation of a predator still exist in horses. The recordings of a grey wolf, an Arabian leopard and a golden jackal were played to 20 Konik polski and Arabian mares. Durations of grazing, standing still, standing alert and the number of steps in walk and trot/canter were measured. In one-minute scans, the distances of the focal horse from the reference horse (DIST-RH) and from the nearest loudspeaker (DIST-LS) were approximated. The vocalisation of a leopard aroused the Arabians more than the Koniks (less grazing, stand-still and walk, more stand-alert and trotting/cantering). Koniks showed more relaxed behaviours to the leopard vocalisation (more grazing, stand-still and walk), but high alertness to the wolf playback (stand-alert, trotting/cantering). Spatial formation of the herd of Koniks showed tight grouping (lower DIST-RH) and maintaining distance from the potential threat (DIST-LS) in response to the wolf howling, while the Arabians approached the loudspeakers in linear herd formation when the leopard growls were played. Adult horses responded to potential predation by changing spatial group formations. This ability to apply a social strategy may be one of the explanations for the least number of horses among all hunted farm animal species.

Abstract: The millennia-old practices of horse training markedly predate and thus were isolated from the mid-twentieth century revelation of animal learning processes. From this standpoint, the progress made in the application and understanding of learning theory in horse training is reviewed including a discussion of how learning processes are employed or otherwise under-utilised in training. This review describes the process of habituation and the most commonly applied desensitisation techniques (systematic desensitisation, counter-conditioning, overshadowing, response prevention) and propose two additional techniques (approach conditioning and stimulus blending). The salience of different types of cues, the interaction of operant and classical conditioning and the impact of stress are also discussed. This paper also exposes the inflexibility and occasional inadequacy of the terminology of learning theory when translated from the research laboratory situation to the practical setting in horse training. While learning theory provides a rich toolbox for riders and trainers, the training process is subject to the simultaneous use of multiple learning processes. In addition, learning/behavioural outcomes and trained responses are not just the result of simple stimulus-response based interactions but are further shaped by arousal, affective and attachment states. More research is needed in these areas. For the field of equitation science to progress and to improve clarity and use of learning processes, changes in nomenclature are required. In particular, the use of the terms 'positive' and 'negative' as descriptive labels in both reinforcement and punishment modalities are unacceptably misleading for everyday use. These labels inhibit the understanding and recognition of the learning processes that these terms supposedly represent, yet the learning processes they describe are vital for horse riders, handlers and trainers to understand. We therefore propose that these labels should be re-labelled more appropriately as 'addition' or 'subtraction' reinforcement/punishment. This would enlighten trainers on the correct application of learning theory, and safety and welfare benefits for people and horses would follow. Finally it is also proposed that the term 'conflict theory' be taken up in equitation science to facilitate diagnosis of training-related behaviour disorders and thus enable the emergence of improved training practices. The optimal use of learning theory should be established as a fundamental principle in equestrian education.

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.

Abstract: Horses, and in particular sport horses, remain housed predominantly in single stalls. One of the main reported reasons is the fear that they will become agitated and injure themselves and thereby impair their performance if released in paddocks. The hour spent daily at work is also assumed to be sufficient to satisfy the horses' needs for locomotion. Growing scientific evidence shows that single stall housing has negative consequences on horses' welfare and that time for free movement is necessary. Our aim was to assess the feasibility of allowing sport horses used to staying permanently in their stall (except for 1 h riding/day) daily free time in a paddock and to evaluate its potential impact on their welfare using two behavioural reliable indicators (stereotypic behaviours and ear position), as well as selected blood parameters (blood cell count, oxytocin and serotonin concentrations). Two experiments were conducted on the same site. The first experiment evaluated sport horses' habituation to the novel situation of daily sessions in a paddock, and recorded welfare indicators in their stall before and during the experiment, comparing horses that were taken outdoors (experimental) and those that stayed in their stall (control). The second experiment evaluated the impact of this daily free time in a paddock on horses' welfare and its durability, focusing on positive indicators. Behavioural observations in paddocks showed that even horses that had never experienced free movement outside their stall habituated rapidly to this situation. The presence of hay in the paddock, may have speeded up habituation. Their restricted living conditions were associated with abnormalities in blood cell count that were not overcome during the time of daily paddock sessions but behavioural indicators showed that their welfare improved. In the second study, the experimental horses' welfare improved during the paddock release period, in particular their stereotypic behaviours decreased and oxytocin levels increased. No effects on serotonin concentrations could be evidenced. These effects were directly associated with being in paddock, as the indicators returned rapidly to their previous levels indicating compromised welfare when the paddock release sessions stopped. In conclusion, it can be recommended to release sport horses for free movement in paddocks as welfare is improved and subjective assessment by caretakers indicated minimal risks.