Horses face the same kinds of stresses and frustrations as humans in their day-to-day lives. It is little wonder they sometimes feel the strain. Researchers are taking an interest in how horses cope with the pressures of training.
Most people know only too well the consequences of too much stress in their daily lives. Perhaps it is from long and arduous hours of work, or a boss who is too picky and demanding.
Researchers have in recent years started looking at stress in the workaday lives of horses, both in training and under saddle across a raft of disciplines.
Can horses buckle under the same kinds of stresses that affect humans?
The answer, it seems, is yes, and the trigger points would appear to be similar: learning difficult new tasks, boring day-to-day routines, poor relationships, negative reinforcement, insufficient rewards, and a troublesome boss (trainer).
All are stress factors for horses, researchers have shown. They can lead to frustration and neurosis in horses, behavioural scientists suggest.
Researchers in Europe have been leading the way in probing the training stresses faced by horses.
Why should horses get stressed in the first place?
Professor Martine Hausberger and her fellow researchers in France note that horses, like people, are often asked to work on a daily basis, involving “interpersonal” interactions not only with other working horses but also with a “boss” – the human who manages or rides the animal.
“Work sessions are based on training, using more often negative reinforcement or punishment than positive reinforcement,” they noted in the findings of recent research.
“Physical and emotional constraints depend also on the type of work performed. Negative consequences of some practices, leading to physical and behavioral resistances, open conflicts and tensions during the work sessions have been described for some time.
“Conflicting signals given by the rider (urge forward with the legs and keep restraining through the mouth/bit) may lead the horse to frustration and neurosis.
“Finally, horses are asked to suppress emotional reactions from their early stages of work on, as such reactions may be contrary to the performance expected (dressage competition) or considered dangerous for the rider (such as bucking).
“Few studies, however, question the possible durable effects of such work stressors – interpersonal conflicts, suppressed emotions, physical constraints – on the daily life of horses outside the work sessions.”
Hausberger, who directs the Department of Ethology at the University of Rennes 1 in France, suggests negative experiences linked to training could lead to chronic states where horses “switch off”, becoming unresponsive and apathetic – states described in humans in cases of work-related burnout.
Abnormal repetitive behaviours in horses are thought to be a way for animals to cope with an unfavourable stress-inducing environment.
So what would seem to be areas of greatest stress?
An Austrian study confirms that starting a horse under saddle causes stress, which rises markedly during the first time a rider gets on the horse.
It seems likely that the horse interprets the first mounting of a rider as a potentially lethal attack by a predator, from which it is unable to escape, the researchers suggest.
“In addition, the rider is outside the horse’s field of vision, which presumably exacerbates the problem,” researcher Alice Schmidt said.
Schmidt and others at the University of Veterinary Medicine, in Vienna, in a study reported in the journal, Hormones and Behavior, measured stress by examining the horses’ heartbeats and the levels of the stress hormone cortisol in their saliva.
In looking at the heartbeat, she considered not only their frequency but also the short-term fluctuations in intervals between the beats, which have previously been shown to be a good indicator for stress.
Schmidt used three-year-old horses at the start of their initial training regimes. Not surprisingly, she found the start of training was a stressful period.
“The initial work on the lunge caused only a moderate amount of stress but the stress level rose markedly when the rider first mounted,” she reports.
This was revealed by an immediate increase in heartbeat and in the fluctuations in intervals between individual beats, as well as by the release of cortisol into the saliva.
When the horse and rider walked or trotted forward, the level of stress decreased somewhat.
“It seems as though the horse adapts rapidly to the idea of being ridden and that – as is the case for humans – exercise may help relieve stress,” she says.
The extent of stress caused by mounting was found to decrease gradually as the horse was trained, provided the training was being done correctly.
Fellow researcher Jörg Aurich cautions that a lack of care or an incorrect regime in early training could cause long-term damage to the relationship between a horse and its rider. It could thus prevent a sports horse reaching its full potential, as well as causing the animal unnecessary anxiety.
Although Schmidt’s results clearly show that the initial training of a sport horse stresses the animal, Schmidt has some reassuring words for trainers and riders.
“The stress caused by being ridden for the first time is nowhere near as much as that caused by being transported by road. And if you are gentle and careful when you start to train a young horse, it will soon get used to you.”
In France, researchers extended stress research to the role of temperament in training.
They found that both stress and temperament influence the learning ability of horses, but it is not altogether simple.
The scientists used 49 female Welsh ponies aged around seven, randomly divided into three groups.
One group of 15 was stressed before a learning task, the second group of 15 was stressed after the same learning task and the third group, of 19 animals, was not stressed at all.
The stress involved exposure to 20 unpredictable sudden events, from unfamiliar objects to loud sounds and sudden movements.
Each of the animals was assessed beforehand for temperament using a method adapted from previous researchers. It assessed five dimensions – fearfulness, group sociability, reactivity to humans, level of locomotor activity, and sensitivity to touch.
The learning task involved training each horse to touch a cone on the ground with its nose for a food reward. The learning task was repeated a week later to determine whether there was any differences between the three groups.
The study, led by Mathilde Valenchon and published in the open-access journal, PLoS ONE, showed that learning performances varied according to the exposure to stress.
Horses stressed before the learning task tended to perform more successes at the beginning of the learning session than the non-stressed horses.
Eight days later, during the re-learning session, the non-stressed animals improved their performance.
Contrary to the non-stressed group, the horses that had been stressed after the learning task, and, to a lesser extent, those stressed before, did not significantly improve their performance.
The researchers found that temperament influenced learning performance, but only when the learning or re-learning performances were affected by stress, suggesting that temperament had little influence on learning ability provided lessons occurred in a stress-free environment.
They found that while direct exposure to a stressor tended to increase learning performance, the state of stress induced by the memory of a stressor during efforts to re-learn or reinforce the task impaired performance.
Further, the negative effect of a state of stress on re-learning the task appeared to be stronger when exposure to the stress occurred after rather than before the learning session.
The results, the researchers said, suggested that stress impaired more cognitive abilities in fearful horses than in less fearful horses.
“The present study constitutes the first evidence that stress modulates the influence of temperament on cognitive abilities in horses,” Valenchon and her colleagues reported.
Valenchon, in another study, explored the effects of stressful situations on the working memory of horses, testing the ability of 30 Welsh pony mares to remember in which of two buckets they would find a carrot.
A researcher dropped a carrot in one of the buckets in sight of the mares. Each horse was made to wait between zero and 20 seconds before being allowed to the bucket to retrieve the carrot.
In a calm setting, the horses were found to have an average working memory of 16 seconds.
However, when the testing was performed under stressful conditions – involving the likes of a barking dog and a waving sheet – they performed much worse.
The mares also underwent temperament assessments, with the researchers finding the more fearful horses performed even worse under stressful conditions, despite generally performing best in the same test in a calm environment.
Researchers have also found that different disciplines induce different levels of stress in horses.
Findings from French research indicate that dressage and high-school work create higher levels of stress in horses than the likes of jumping, eventing and vaulting.
The scientists from the University of Rennes 1 explored whether the daily work to which many horses are exposed could result in the same sorts of stresses experienced by people in their work environments.
The findings, published in PLoS ONE, indicate that horses, like people, face stresses in their daily life involving troublesome human bosses, difficult interpersonal relationships, undue negative reinforcement and poor rewards.
Such negative experiences linked to training could lead horses to switch off, becoming unresponsive and apathetic – the equine equivalent of work-related burnout in people.
The researchers – Hausberger, Emmanuel Gautier, Véronique Biquand, Christophe Lunel, and Patrick Jego – set about studying 76 French Saddlebred horses stabled at the Ecole Nationale d’Equitation in Saumur.
The horses, aged six to 15, were all geldings and housed in the same conditions, spending 23 hours a day in their stables. They received the same diet. The only difference was in the kind of discipline they performed each day for an hour.
The scientists monitored the horses in their stables for behaviors called stereotypies – abnormal repetitive behaviors which serve no useful function. These include repetitive mouth movement, head tossing or nodding, wind-sucking, cribbing and weaving.
They found that the type of work performed by the horses each day had a significant influence on the prevalence and types of undesirable traits shown.
“To our knowledge, this is the first evidence of potential effects of work stressors on the emergence of abnormal behaviors in an animal species,” the researchers noted.
“It raises an important line of thought on the chronic impact of the work situation on the daily life of individual [horses].”
The researchers found that 65 of the 76 subjects performed some type of stereotypy.
The horses were categorised as doing one of three kinds of work:
Vaulting horses appeared to be the least prone to stereotypies whereas dressage/high-school horses presented the highest incidence of such undesirable traits. Several of these horses performed two or more types of stereotypies.
They also performed the stereotypies considered to be more serious – cribbing, windsucking and head shaking.
The authors pondered why dressage appeared to cause the most stress.
“Dressage and high school both expect horses to restrain from expressing emotions and put a strong physical constraint on the movements,” they noted.
“Moreover, cases where orders can be conflictual are more frequent here as the restricted gaits are often obtained by refraining movement through the reins and bit while pushing forward the horse through the legs.
“Therefore both physical and interactional stress can explain the high prevalence and types of stereotypies observed in these horses.
“Jumping, eventing or instruction horses were trained more to take long strides while moving forward in a less ritualised posture. These horses performed more repetitive licking or biting of environmental structures.”
These, they said, are often considered to be early stages of stereotypy.
“Whether these horses would develop more serious stereotypies with time appears unlikely as they remained under these conditions for at least one year and often more. Maybe they were reacting mainly to the general unsuitable conditions (social separation …) they were housed in.
“Finally, vaulting horses appeared the least prone to perform stereotypies and these were restricted mainly to tongue play. Vaulting horses had been chosen for their quiet temperament and spent their work time turning in circles, with voice orders.
“Interpersonal conflicts with the human are rather limited as they are just required to keep regular and slow paces, while accepting humans to make movements on their backs. Their originally quieter temperament may also make them more resistant to possible work stressors as observed in humans.”
The authors pointed to earlier research suggesting that head shaking may be a lasting effect of strong bit action, resulting from damage to the trigeminal nerve, as riders work to keep their horse’s head down.
This would explain why headshaking and nodding were performed more often by dressage horses as for most of their working time they have to keep their necks flexed in restrained gaits, they said.
“Although some work stressors involved here may be specific to equine work, others are clearly shared with other species, including humans: emotion suppression, interpersonal conflict, physical demands, lack of reward and negative future expectancy that are associated with depression in humans.
“The present study opens clearly new and further lines of thought about, on one hand, the causation of abnormal repetitive behaviours, on another hand the effects of work stressors not only on well known expressions of psychological disorders such as depression or burnout but also on the possible emergence of abnormal behaviour.
“The very controlled restricted locomotion allowed in dressage and especially high-school horses associated with rapid transitions may explain an increase of reactivity, especially when bit pressure and spurs induce additional aversive stimulations.
“The higher emotional responses of dressage horses in emotional tests provide further support for this hypothesis. Collected gaits may also be physically very demanding and these difficulties may frustrate the horse, but also its rider who can transmit additional nervousness.”
The authors noted that other factors can be involved in development of stereotypies, including roughage availability, diet, social deprivation, lack of exercise and genetic susceptibilities. The length of time spent in stalls may also have an influence.
However, the results clearly showed that the discipline being performed by the horse influenced the degree to which they showed undesirable traits.
“We showed that, for a variety of reasons (physical, emotional …) the limited time spent with humans might affect the remaining daily life of the horses.
“This may well be true for other situations such as handling, feeding, transporting animals. These results also raise the question of how different types of repetitive movements may develop.
“While some may be explained by lasting effects of physical constraints, others may emerge through chronic stress.”
Of the 76 horses, 10 undertook eventing, 19 were show jumpers, seven worked in an advanced riding school, 17 performed dressage, 16 were high school horses and seven were used in vaulting.
In a related theme, British research showed the importance of matching a horse’s temperament to different equestrian disciplines.
The study involved a comprehensive review of psychological factors affecting equine performance.
The research, published in the open-access journal BMC Veterinary Research, explored issues surrounding training, competition environment and practices, and how the psychology of horse mood, emotion and temperament could be used to enhance performance.
British researchers Dr Sebastian McBride, from the Royal Agricultural College, and Professor Daniel Mills, from the University of Lincoln, looked at how current behavioral research and already-established behavioral modification techniques could be applied to enhance the performance of competition horses.
This included matching a horse’s temperament to different equestrian disciplines. For example, flightiness can be good for racing but detrimental for dressage.
“Another important consideration is the horse’s mood and emotional reaction,” McBride said.
“Although all of these have an intrinsic baseline observable in the young, untrained horse, they can be influenced by training and they are also dependent on the interaction between rider and horse.
“Competition riders are well aware how a strange environment, and nerves on competition day, can affect their horse’s performance.”
Mills continued: “The increased competitiveness and performance level of equestrian sport means that for each horse and rider pair, physical and psychological behavior must be taken into consideration when designing training conditions and increasing motivation to perform at the optimum level of athletics.
“They must also be applied to reducing over-emotional reactions on competition day and, given the trained horse’s high motivation to succeed, to decrease any negative experiences at competitions which may otherwise impact on future events.”
The researchers noted that increased competitiveness and the performance level in sport now required that individuals and teams must give over a substantial amount of time to their respective disciplines.
The pair identified areas within the current performance horse industry where known behavioral research and behavioral modification techniques could be applied to enhance the performance of those animals.
These included ensuring optimal environmental conditions for the horse, and using behavioural modification techniques to:
- Sufficiently motivate the animal to perform the correct athletic behaviour.
- Reduce overly reactive behaviour in anticipation of the competitive event.
- Reduce emotionally reactive behaviour to novel stimuli associated with the competitive event.
- Reduce motivated behaviors in response to stimuli associated with competition events that are a result of previous negative experiences linked to those stimuli.
The pair noted that, despite its obvious importance, there was remarkably little research into any aspect of the psychology of equestrian performance.
They said psychological factors existed at three inter-related but separate levels: temperament, mood and emotional reaction.
Temperament existed as a relatively stable factor in adult life, they noted, having been shaped by genetic makeup and early experience, whilst mood described a more temporary psychological state.
Emotional reactions were the most tightly stimulus-bound affective states and the shortest lived temporally, describing the more immediate response to a situation.
“If mood is negative then there is a higher probability of negative emotional reactions to a given situation,” they wrote.
“Whilst there is a growing literature on temperament in horses, there is still very little scientific work on the emotional reactions of horses and almost none on the assessment of moods.
“It is nonetheless important to appreciate that although it is difficult to study these phenomena, this does not mean that they are not important and certainly that they do not exist.”
In their review of temperament, they said it was clear that more validation-type research was required to measure early temperament traits with a view to matching them with equestrian disciplines.
They said both mood and emotional state were crucial in determining how a horse perceived and reacted to its environment and thus how it would perform within a training and competition environment.
“Positive mood is essential for all disciplines, but the optimal emotional state leading to optimal emotional arousal can vary between disciplines and between horses, as in the case with humans,” they said.
“Over-reaction as the result of high emotional arousal is detrimental to performance and is heavily influenced by prior training techniques and also the emotional state of the rider.
“More extensive research is required within both of these areas,” they said.
The pair said many horses may fail in competition because of the difference between the training and competition environments and thus the lack of training to generate appropriate emotional and behavioral responses to competition.
“It follows, therefore, that one of the most important factors at the outset of training is to ensure that the individual animal is sufficiently motivated to perform.
“Interestingly, in human sports performance psychology, this motivation either to succeed or to avoid failure is so enhanced in some individuals that it often develops clinically as obsessive-compulsive characteristics, referred to as perfectionism.”
Motivation to learn is also heavily affected by the learning environment, they said, in particular the duration of the training session and how frequently those sessions occur on a daily or weekly basis.
“The level of motivation to perform will be determined by the type of learning taking place (for example, negative versus positive reinforcement) and the complexity of the task.”
In this respect, much more research was needed to establish optimal training schedules for specific equestrian tasks, they said.
To compete successfully in competition, regardless of the discipline, it was important that the horse is highly motivated to perform the specific athletic activity at the outset of both training and competition.
“The performance horse also needs to be motivated at the time of competition, but not to the extent that any restriction of that motivated behavior has a negative effect on the animal’s physiological or psychological state.
“Highly motivated horses, however, can be exposed to behavioral modification techniques in order to attenuate specific unwanted behaviors, but the animal must be capable of responding to these techniques in a positive way.
“Modification techniques can also be applied to highly reactive horses that are responding to novel stimuli or previous negative experiences, but again those individuals need to be responsive to those techniques.”
Not so negative
A Danish study that looked at negative reinforcement in training reveals that it may be beneficial in getting horses used to unfamiliar objects, but comes with a warning over stress responses in animals.
The results of the study by Janne Winther Christensen, of Aarhus University, was published in the Equine Veterinary Journal.
Christensen said the ability of horses to get used to novel objects influences safety in the horse-human relationship. However, the effectiveness of different ways of habituating horses had not been investigated in detail.
Christensen set about investigating whether horses showed increased stress responses when negatively reinforced to approach novel objects, compared to horses that were allowed to voluntarily explore the objects.
The research also set out to discover whether negative reinforcement aided object habituation.
Twenty-two 2 to 3 year old Danish Warmblood geldings were used in the study.
Half were negatively reinforced by a familiar human handler to approach a collection of novel objects in a test arena. The other half of the horses – the voluntary group – were individually released in the arena and were free to explore the objects.
On the next day, the horses were exposed to the objects again without a human to allow the rate of habituation to be investigated.
Behavioural and heart-rate responses were recorded during the study.
Christensen found that all horses in the voluntary group initially avoided the unknown objects, whereas the handler was able to get all negatively reinforced horses to approach and stand next to the objects within the first two-minute session.
The negatively reinforced horses had a significantly longer duration of alertness and a higher maximum heart rate in the first session. On the following day, however, the negatively reinforced horses spent significantly less time investigating the objects and approached a feed container, placed next to the objects, faster than the voluntary group, indicating increased habituation.
Christensen found that while the approach using negative reinforcement aided habituation in young horses to approach novel objects, there was an increased stress response during initial exposure.
“Although negatively reinforced approach appears beneficial for habituation, the procedure should be carefully managed due to increased stress responses in the horse which may constitute a safety risk,” Christensen said.
“Further experiments should aim to investigate differences in stimulus intensity.”
Ironically, it seems that horses properly trained for the competition environment do not suffer from one of the curses of human performance – stage fright.
Austrian research suggests horses do not suffer from stage fright in front of an audience – but their riders most certainly do.
The researchers set about determining whether the familiar signs of stage fright, with all its nasty manifestations such as rapid pulse, dry mouth, shaky voice, blushing and sweaty palms, affected horses.
Was the condition restricted to humans, they wondered? How do animals react to the presence of human audiences?
Professor Christine Aurich and her team at the University of Veterinary Medicine, in Vienna, tackled the questions.
Their research confirms that horse riders suffer more stress when performing in front of an audience than when practising for the event, but show that the horses themselves react identically whether or not spectators are present.
The horses and their riders thus perceive the challenges of competing in equestrian events differently, the scientists concluded.
Little attention has been paid to the effects on riders, the researchers noted. That was surprising, they said, given that equestrian sports relied on the close co-operation between the animals and their riders.
The research was undertaken by Mareike von Lewinski in Aurich’s group, together with colleagues at the university and at the Ecole Nationale d’Equitation in Saumur, France.
The scientists measured the changes in various stress-related parameters, such as the level of stress hormones in saliva and the regularity of the pulse, in horses and their riders when the animals were ridden in a particular show programme.
The measurements were taken both when the presentation was completed in front of about a thousand spectators and when the riders practised beforehand without any spectators.
The results were compared to assess how the riders and their mounts responded to the presence of the audience.
In line with previous experiments, the researchers could observe symptoms of stress – higher cortisol concentrations in the saliva and more irregular heartbeats – both in horses and in their riders during the study.
But the riders showed significantly higher levels of stress when an audience was present, confirming what was suspected – participation in equestrian events is associated with stage fright, even in experienced riders.
There are many reasons why riders might be more stressed when performing in front of an audience than when practising. As Aurich says: “They are only human, after all.”
In contrast, the horses appeared not to be affected by the presence of spectators: their reaction to the course was essentially independent of whether an audience was present or not.
In other words, the horses and their riders respond differently to the challenges posed by performing for spectators, with the horses not suffering from the increased levels of stress shown by their riders.
The results imply that the riders do not communicate their heightened anxiety to the animals.
The lack of transfer of emotions between rider and horse was completely unexpected.
Aurich concedes: “We started with the assumption that the rider’s stress would affect his horse but this does not seem to be the case.
“Nevertheless, we should bear in mind that we were working with experienced horses and highly skilled riders: our findings cannot be generalized to inexperienced riders, who might be less able to prevent their horses from being stressed by the situation.”
Changes in cortisol release and heart rate and heart rate variability during the initial training of three-year-old sport horses, by Alice Schmidt, Jörg Aurich, Erich Möstl, Jürgen Müller and Christine Aurich, is published in the September issue of the journal Hormones and Behavior. The work was carried out at the University of Veterinary Medicine, Vienna and the Graf Lehndorff Institute for Equine Science, Neustadt (Dosse), Germany.
Valenchon M, Lévy F, Prunier A, Moussu C, Calandreau L, et al. (2013) Stress Modulates Instrumental Learning Performances in Horses (Equus caballus) in Interaction with Temperament. PLoS ONE 8(4): e62324. doi:10.1371/journal.pone.0062324. The full study can be accessed online here.
The paper Changes in cortisol release and heart rate and heart rate variability during the initial training of three-year-old sport horses by Alice Schmidt, Jörg Aurich, Erich Möstl, Jürgen Müller and Christine Aurich is published in the September issue of the journal Hormones and Behavior.
The work was carried out at the University of Veterinary Medicine, Vienna and the Graf Lehndorff Institute for Equine Science, Neustadt (Dosse), Germany.
Object habituation in horses: The effect of voluntary vs. negatively reinforced approach to frightening stimuli.
Janne Winther Christensen
“Cortisol release, heart rate and heart rate variability in the horse and its rider: Different responses to training and performance”. It is written by Mareike von Lewinski, Sophie Biau, Regina Erber, Natascha Ille, Jörg Aurich, Jean-Michel Faure, Erich Möstl and Christine Aurich.