Abstract: Crib-biting is a common oral stereotype. Because of perceived deleterious effects on the health and appearance of subjects the prevention of crib-biting is regularly attempted. The resourcefulness of horses in satisfying their motivation to perform this behaviour often frustrates owners' efforts at prevention. This paper reviews the efficacy and observable consequences of attempting to prevent crib-biting by a variety of methods. These include attempts to prevent the grasping of objects, to interfere with air-engulfing and to introduce punishment for grasping and neck-flexion. Other approaches include the use of surgery, acupuncture, pharmaceuticals, operant feeding and environmental enrichment. A remedy that is effective for every crib-biter remains elusive. We conclude that, rather than concentrating on remedial prevention, further research should be directed at establishing why horses crib-bite and how the emergence of crib-biting can be avoided.

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: Many behaviours in domestic animals, such as the 'stable vices' of horses, are treated because they are considered undesirable for economic or cultural reasons, and not because the activity affects the horse's quality of life. The impact of a behaviour on the human reporter is not a function of its impact on the animal performer, and an understanding of the causes and effects of the particular activity is necessary to assess the costs and benefits of treatment. Where the behaviour is a sign of poor welfare, such as an inadequate environment, treatment can best be achieved by removing these underlying causal factors. Pharmacological or physical prevention of a behaviour can be justified only if the behaviour causes harm to the performer or to others. In these cases, prevention of the behaviour without addressing its causes is no cure and may result in its perseverance in a modified form or the disruption of the animal's ability to adapt to its environment. Where the behavioural 'problem' causes no harm and is not related to poor housing, then the education of the reporter, rather than treatment of the performer, may be the best solution.

Abstract: Forty-one Dutch Warmblood immature horses were used in a study to quantify temperamental traits on the basis of heart rate (HR) and heart rate variability (HRV) measures. Half of the horses received additional training from the age of 5 months onwards; the other half did not. Horses were tested at 9, 10, 21 and 22 months of age in a novel object and a handling test. During the tests, mean HR and two heart variability indices, e.g. standard deviation of beat-to-beat intervals (SDRR) and root mean square of successive beat-to-beat differences (rMSSD), were calculated and expressed as response values to baseline measures. In both tests, horses showed at all ages a significant increase in mean HR and decrease in HRV measures, which suggests a marked shift of the balance of the autonomic nervous system towards a sympathetic dominance. In the novel object test, this shift was more pronounced in horses that had not been trained. Furthermore, statistical analysis showed that the increase in mean HR could not be entirely explained by the physical activity. The additional increase in HR, the nonmotor HR, was more pronounced in the untrained horses compared to the trained. Hence, it is suggested that this nonmotor HR might be due to the level of emotionality. HR variables showed consistency between years, as well as within the second year. These tests bring about a HR response in horses, part of which may indicate a higher level of emotionality; and horses show individual consistency of these HR variables over ages. Therefore, it is concluded that mean HR and HRV measures used with these tests quantify certain aspects of a horse's temperament.

Abstract: Single species aggregations are a commonly observed phenomenon. One potential explanation for these aggregations is provided by the selfish herd hypothesis, which states that aggregations result from individual efforts to reduce personnel predation risk at the expense of group-mates. Not all movement rules based on the selfish herd hypothesis are consistent with observed animal behavior. Previous work has shown that herd-like aggregations are not generated by movement rules limited to local interactions between nearest neighbors. Instead, rules generating realistic herds appear to require delocalized interactions. To date, it has been an open question whether or not the necessary delocalization can emerge from local interactions under natural selection. To address this question, we study an individual-based model with a single quantitative genetic trait that controls the influence of neighbors as a function of distance. The results indicate that predation-based selection can increase the influence of distant neighbors relative to near neighbors. Our results lend support for the idea that selfish herd behavior can arise from localized movement rules under natural selection.