Figure 11.1 Equine Prisoners Model; based on Fraser et al. (1997) and Henderson (2007)
Not quite a pet, yet certainly a more intimate companion than agricultural livestock, the modern sport horse holds a unique position in the human-animal dynamic. The term “sport horse” (sometimes referred to as “performance horse” or “show horse”) refers to those horses that are bred for and perform at the higher echelons of equestrian sport in the traditional Olympic disciplines of show jumping, three-day eventing, combined driving and dressage, and are generally of European bloodlines. It is these equine elite that I am referring to in this chapter.
In spite of over 6000 years of domestication (Budiansky 1997) that has selected for a myriad of highly specialised physiological and psychological attributes designed for demanding disciplines, the horse’s ethological needs for continual foraging, movement and social interaction have changed little from those of their ancestors (e.g. Christensen et al. 2002). Yet today’s current sport horse husbandry practices too often fall short in meeting those needs.
Feral1 horses typically live in bands or harems consisting of one dominant stallion, several adult mares and their young offspring. Herd stability is paramount for survival and bands form cohesive units, with members often remaining together for life (Araba and Crowell-Davis 1994). To make the best use of the available food resources, bands graze almost continuously over large territories, varying in size from 1 to 48 square kilometres (Kieper 1986). The feral horse’s life of liberty comes with a price; horses are vulnerable to the perils of predators, parasites, harsh climatic changes and scarce resources, making survival a precarious business.
Domestication over the millennium has necessitated more intensive management practices to arrive at the extreme end of the continuum evidenced in the housing of the modern sport horse. These horses, in contrast to their ancestors, are safely housed in luxurious multi-million dollar facilities, exercised and groomed regularly and see a plethora of healthcare professionals (farriers, veterinarians, grooms, chiropractors, massage therapists etc.). These horses can usually see their equine neighbours but not touch them. Some are afforded “turn-out” (time spent outside of the stall in small paddock enclosures for a few hours per day). Contact with other horses is discouraged with electric wire or double fencing separating enclosures. The dietary norm for today’s North American sport horse, emphasising quality and necessarily limited in quantity, consists of highly palatable concentrates and rich timothy or alfalfa hay all of which is consumed quickly, leaving the horse for many hours in the stall with an empty stomach and nothing to do. When domestic horses are given the opportunity to live in natural conditions, their social organisation and time budgets are similar to those of their feral counterparts – forming lifelong, stable, social groups and foraging 16–20 hours per day over vast home ranges (Cooper and Albentosa 2005; Feh 2002).
Undoubtedly, as many equine scientists have suggested, today’s sport horses’ psychological wellbeing would be immeasurably enhanced from living with their herd mates on the open range, grazing at liberty on medium quality roughage (e.g. Luescher, McKeown and Halip 1991; Sarrafchi and Blokhuis 2013). However, this is not a solution that is generally palatable and/or feasible for owners or equine facilities managers, who assume responsibility for 15 to over 100 sport horses at a boarding facility, where horses are housed, fed, turned out for exercise and maintained, and owners come regularly to ride and receive coaching. Not only are owners protective of their costly investment, most develop a strong bond with their horses. Competing and working intensely with an animal over a number of years toward specific competition goals enhances this bond. Most riders describe their horses as they would a best friend and care intensely about their wellbeing. They fear their horses will injure themselves if provided greater liberty, let alone liberty with other horses. In an increasingly litigious society, stakeholders are reluctant to take what they believe to be unnecessary risks. Owners who sustain extravagant costs at a training facility expect their performance horses to feed on the best quality hay and grain, and to look the part of a sleek sport horse. Even if owners were willing to allow their horses a more “natural” existence, prohibitively costly real estate makes pasture acreage a luxury many facilities cannot provide. Thus, most sport horses live a life far removed from their ancestors – where the evidence presented in this chapter will suggest that their well-intentioned owners have subjected them to a life of significant suffering.
My focus is to illustrate how we might bridge the divide between the disparate lifestyles of sport horses and their free-ranging ancestors. A walk down the aisle of a typical sport horse training facility, with horses housed in spacious, deeply bedded stalls, or enjoying an appointment with their massage therapist does not bring images of animal cruelty to mind. Certainly few owners would knowingly consent to their animals being abused. However, as I will outline in this chapter, the psychological and physiological wellbeing of today’s sport horse is compromised; their suffering is immense, invisible and thankfully reversible. Relatively minimal management changes can enhance sport horses’ wellbeing without compromising the goals of industry professionals and owners.
In a theoretical paper discussing the assessment of animal welfare, Fraser and colleagues have proposed an “integrative model” to assess all animal welfare (Fraser et al. 1997). In the accompanying figure (see Figure 11.1) I have modified their model to fit specifically the dilemma of the modern sport horse (entitled “The Equine Prisoner’s Model”). Circle A depicts the “evolved adaptations” that horses bring to their present environment, and Circle B depicts the “environmental challenges” that these horses must currently meet. When horses live in the environment for which they were evolutionarily designed, adaptations and challenges correspond, and the overlap between the circles is large; when they are moved out of their natural environment, as is the case with sport horses, the circles no longer overlap entirely. It is this imperfect correspondence between adaptations and challenges that becomes critical for sport horse welfare.
In the area to the left of the overlap, we have the horse’s evolved adaptations that no longer serve a useful purpose. Here, we can place the feral horse’s hair trigger flight response, the aptitude to form stable and lasting pair bonds with conspecifics, or the capacity to live on poor forage spread over large territories. We compromise the sport horse’s welfare because the adaptation includes a motivational need to perform behaviours that now have no outlet for expression (e.g. a motivational need to graze is frustrated when the horse has no access to pasture), while simultaneously blocking the positive benefits associated with that behaviour (e.g. grazing promotes healthy gut functioning, exercise, opportunities for socialisation etc.)
In the area to the right of the overlap we have challenges in the environment for which the horse does not possess the corresponding adaptations. Here we can situate equine welfare problems discussed in this chapter such as the failure to cope with confinement, social isolation and a concentrated, high quality, low quantity diet.
In the centre overlap we have challenges faced by horses for which they do possess the corresponding adaptations. This would include qualities such as the horse’s strength, athleticism and an evolved social structure, based on dominance hierarchies, that predisposes horses to willingly acquiesce to the one in charge. These characteristics are what have allowed us to domesticate the horse so successfully through the centuries as a beast of burden, method of transport and now primarily for sport (Budiansky 1997).
A perfect correspondence of adaptations and challenges does not necessarily ensure optimal welfare; a starving pregnant mustang is living in the environment for which she was evolutionarily designed. When we have orchestrated the horse’s transfer into an environment of our choosing, however, this places a moral responsibility on industry professionals and owners to present these horses with challenges that are within reach of their adapted behavioural and psychological limits – that is, to increase the overlap of Fraser’s circles (see Figure 11.1).
Since horses make difficult research subjects due to obvious language barriers, and consistently perform well in spite of immense physiological and psychological suffering (injuries, lameness, ulcers, depression, anxiety etc.), measuring equine wellbeing has been an imprecise science. When adaptations have no outlet for expression, but where the motivation to perform them remains high, the expression of these behaviours may surface in the form of stereotypies. Albeit a crude measurement, the presence of stereotypies provides a starting point for exploring equine wellbeing.
Stereotypies, observed in a wide variety of species living in captivity, have been defined as repetitive behaviours that follow a ritualised, invariant sequence and appear to serve no obvious purpose (Houpt and McDonnell 1993; Luescher, Mc Keown and Halip 1991). The stereotypy is thought to derive from a normal behaviour to satisfy a goal which cannot be satisfied in the current environment. The resulting behaviour becomes an abbreviated version of what was once a purposeful and normal activity, and, as the stress is prolonged, the behaviour becomes repetitive, invariant and chronic.
Examples of stereotypies include Weaving, where the horse remains stationary, but shifts weight between the front legs, or among all four legs. This may originate as an impeded walking sequence where a stall-bound horse is highly motivated to reach an intended goal – most likely, food, companions or freedom – but is prevented from doing so. Cribbing – where the horse grasps the edge of a horizontal surface with the front incisors, and extends and draws the neck backwards to produce a burp-like sound, or windsucking which is accomplished without holding onto any surface – both appear to be associated with frustrated feeding behaviour. Stall-bound horses generally consume their typically rich and highly palatable feeds quickly, and thus satisfy their biological needs while the motivational drive to forage remains acute (Henderson 2007; Sarrafchi and Blokhuis 2013; Wickens and Heleski 2010).
Evidence for stereotypies being indicative of compromised welfare is apparent when considering the context in which they develop. They are greater in single-housed than group-housed animals, associated with restricted diet and impoverished environments, are greater in intensely managed systems for horses in demanding disciplines and may result in self-damage (e.g. as in self-mutilation) (Mason and Latham 2004; McDonnell 2008; Sarrafchi and Blokhuis 2013). Although appearing relatively benign, less extreme stereotypies (e.g. mild stall walking, head nodding, or tongue playing) may still indicate welfare issues, and have been associated with the later development of more serious stereotypic behaviour (Nicol 1999; Waters, Nicol and French 2002).
Indeed, since stereotypies have never been observed in free-ranging feral horses, yet are seen at rates of 2.5 percent to 67 percent in domesticated horses (McGreevy, French and Nicol 1995b; Waters, Nicol and French 2002, Visser, Ellis and Van Reenen 2008), stereotypies have more aptly been named the “disease of domestication” (Marsden 2002).
From a human perspective, modern day equestrian facilities are designed with the horse’s best interest, health and safety at heart, yet confront horses with environmental challenges that stretch their ability to adapt. Confinement, solitary confinement, high quality/low quantity diets and the extra toll of competition all place extraordinary demands on today’s sport horses, which they often endure so invisibly that their suffering is not readily apparent.
Horses have been evolutionarily designed to forage over large territories, and periodically explode with sudden bursts of speed to flee actual or perceived threats. Sport horse stables that afford little or no turn-out, or turn-out in tiny enclosures compromise wellbeing by thwarting this innate desire to move. Studies across the globe overwhelmingly come to the same robust finding that as the time outside of the stable increases, rates of stereotypic behaviour decrease (e.g. Lesimple, Poissonnet and Hausberger 2016). Although confinement is stressful, it is the solitary nature of that confinement that exerts the heavier toll on these highly social animals. The fact that stereotypies are almost never seen in cavalry mounts (Houpt and Ogilvie-Graham 2002) and mares used for urine collection to make estrogen supplements (Houpt, Houpt and Johnson 2001; Flannigan and Stookey 2002) who live in highly restricted tie-stalls, but can touch and interact with neighbours, speaks to fact that tactile companionship may be even more important than freedom (Houpt, Houpt and Johnson 2001).
Recent research is providing convincing causal evidence about the link between impoverished environments and the development of stereotypies. For example, Yarnell and colleagues found when horses were group-housed with full visual and tactile contact with conspecifics, they showed the lowest physiological indicators of stress (heart rate, eye temperature, cortisol levels etc.) and were also the easiest to handle. When housed singly, with no social contact, they experienced the highest stress responses and were also much more difficult to manage (Yarnell et al. 2015). The repeated measures design (i.e. the same horses participated in each of the housing conditions) demonstrates that the restrictive housing was the contributing factor to the horses’ increasing stress and decreasing compliance.
In an elegant prospective study, Visser, Ellis and Van Reenen (2008) examined the impact of first time stabling on 36 two-year-old, non-stereotypic, Warmblood colts and fillies. For 12 weeks half the horses were housed in individual stalls while the other half pair-shared a larger stall. Strikingly, by the study’s end, 67 percent of the individually stalled horses developed serious stereotypies such as cribbing and weaving, whereas none of the pair-housed horses did so. Since none of the horses exhibited stereotypies at the study’s onset, this longitudinal study provides a convincing causal link between social isolation and development of stereotypies.
In short, housing horses in individual stalls may be a great idea for humans, but is a poor idea for horses. As Davidson comments, “Stabling our horses usually benefits only one half of the horse-human relationship – the human” (1999, 9).
Since many sport horse trainers and facilities managers mistakenly believe that horses learn stereotypies from one another, “offenders” are commonly isolated, further compromising their welfare (e.g. McBride and Long 2001). However, there has been no evidence for this “copycat” hypothesis (Nicol 1999; Wickens and Heleski 2010), nor that horses learn any behaviours by modelling conspecifics (Houpt 1998; Murphy and Arkins 2007). One explanation for purported stereotypy mimicry, is that the environment that precipitated the development of a stereotypy in one horse will do so in another (Houpt and McDonnell 1993). Ninomiya (2007) proposes that stereotypies may appear to be “copied” only if the non-stereotypical horse is motivated to learn the behaviour – in other words, both the “demonstrator” (the stereotypic horse) and the “observer” (the non-stereotypic horse) are living in a stressful environment. Observers pick up olfactory and visual stress cues from the demonstrator, which intensifies the stressful environment, the observer tries out the stereotypy, the behaviour is rewarded through the dopamine neural pathway, and stress is reduced. Consequently, the reinforced behaviour will continue to be performed in the future.
The typical sport horse diet of high quality, and necessarily limited quantity, concentrates and forage is problematic for horses designed to spend the majority of their time budgets grazing. Their psychological drive to forage remains long after their meal has disappeared, making them vulnerable to the development of stereotypies. Long periods with an empty stomach also makes horses vulnerable to equine gastric ulcer syndrome (EGUS), the result of an imbalance between the protective and acid producing functions of the stomach. Designed to have a consistently full gut, horses produce gastric juices constantly, and when there is no food to buffer them the protective stomach tissue is eroded. Indeed, the association between an empty stomach and the formation of ulcers is so reliable that food deprivation is used as a mechanism for creating ulceration in research animals (Murray and Eichorn 1996; Murray, Eichorn and Jeffrey 2001). Clinical signs of ulcers include weight loss, poor appetite, listless performance, depression and gastrointestinal discomfort. However, symptoms can be sufficiently subtle as to go undetected. A definitive confirmation of EGUS is only possible through endoscopy (Murray, Eichorn and Jeffrey 2001; Murray 2004). Endoscopically proven prevalence rates have been reported in 58 percent – 66 percent of hunter, jumper and dressage horses (Luthersson et al. 2009; Marqués et al. 2011), and a surprising 53 percent of pleasure horses (Luthersson et al. 2009).
The prevention and cure of ulcers is straightforward; temporarily easing the training regime and pasture turn-out (or, next best, free-choice hay) will cure ulcers in a matter of days. The medication, Omeprazole ®, which suppresses gastric acid secretion and increases gastric juice pH, is a standard, highly effective treatment. However, most researchers concur that medication needs to be accompanied by management changes to promote ulcer healing and prevent reoccurrence (e.g. Sutton 2014).
Jones and McGreevy (2010) comment that we set out extraordinary challenges for the horse in competition, because the desire to win goes beyond the notions of fun or even success; it requires that we outperform other competitors. By definition, each successful competition requires increasingly greater challenges. As challenges increase, animal welfare is compromised. And, because competition requires practice, more intense, longer, harder training of increasing difficulty, welfare is again compromised (more travel, more social isolation, changing environments, changing feeding schedules, changing social groups, and more taxing performances). Even at home, competition horses face numerous environmental challenges outside of their evolutionary adaptations, which are further exacerbated when on the road. McClure and colleagues (2005) found that exposing horses to a simulated typical horse show environment (transport to and from the site, and housing without turn-out, in an unfamiliar environment) reliably produced ulceration in horses without pre-existing ulcers, and could do so in less than 5 days.
There is some evidence that stereotypies may serve as an adaptive mechanism, so called do-it-yourself enrichments (Mason and Latham 2004), that may act as a buffer against psychological distress (Cooper and Albentosa 2005; Fejsáková et al. 2013; McGreevy 1997). The complex relationship among stereotypies, palatable grains and the release of beta endorphins supports the notion of the coping mechanism (Dodman et al. 1987; Gillham et al. 1994; Pell and McGreevy 1999). These sweet grains trigger a release of opioid peptides in the central nervous system, which then bind to and activate the parts of the brain associated with stereotypies and intensify the stererotypic behaviour (Gillham et al. 1994). Equine stereotypies are also believed to provide a “mantra effect” similar to that described by individuals on the autism spectrum, who note the calming and focussing properties of “stimming” (repetitive and stylized pacing, rocking, twirling etc.) (Mason and Latham 2004).
Cribbing may also offer relief for ulcers by momentarily extending the stomach and releasing pressure on ulcerated tissue, while increased salivary flow attenuates the acidity of stomach excretions. The erroneous belief that cribbing causes colic is more likely explained by the presence of ulcers, which, when treated, often reduces the occurrence of both.
Convincing support for the “coping hypothesis” has been provided by Briefer Freymond and colleagues (2015) who experimentally induced a physiological stress response with a synthetic adrenocorticotropic hormone (ACTH) injection in a group of cribbers and non-cribbers, and then compared physiological indicators of stress such as heart rate and salivary cortisol levels. Chronic cribbers who cribbed during the ACTH test had salivary cortisol levels similar to non-cribbing controls, whereas chronic cribbers who did not crib had elevated cortisol levels.
Although this research suggests that some stereotypies may be partially successful in coping with environmental deficiencies, we cannot then assume that simply allowing their continued expression ensures good welfare. A weaving horse will not experience improved psychological wellbeing by simply being allowed to weave. To significantly improve welfare, one must also address and satisfy the end goal – in the weaver’s case, undoubtedly, contact with other horses.
Returning to the Equine Prisoner’s Model, stereotypies may serve as the horse’s own attempt to embrace the more desirable overlap area in the model – environmental challenges for which the horse does possess the corresponding adaptations. This valiant, albeit not entirely effective, new adaptation to reduce physiological arousal in stressful circumstances is possibly the horse’s best bid to gain a modicum of control in an uncontrollable situation.
Horses meet yet another roadblock when they are prevented from performing the very behaviours that may alleviate their distress in an adverse environment. This new, compounded, welfare problem may be one of the most egregious, albeit inadvertent, cruelties (Briefer Freymond et al. 2015; Cooper and McGreevy 2002; Hothersall and Casey 2012; McGreevy 1997, Wickens and Heleski 2010). Cribbing, in particular, has precipitated a wealth of “remedies”.
Various collars that reduce or eliminate cribbing by applying pressure, electric shocks or spikes into the neck are common industry practice. However, McGreevy (1997) found that collars reduced cribbing while on, but when removed, horses cribbed more aggressively. Consequently, the collars actually result in an increased motivation to crib.
“Cribbing rings”, inserted through the gums between the upper incisors, cause pain in the gums when the horse attempts to crib. Some veterinarians have suggested using larger rings drilled into the bone, as these are less apt to shift (Campbell Smith 2006; Smith-Thomas 2009).
Surgical intervention, the “Modified Forssell’s Myectomy”, involves cutting out a section of the ventral branch of the spinal accessory nerve on both sides of the neck along with major neck muscle tissue. Although marketed as a successful procedure, particularly if performed at the first instance of cribbing (Baia et al. 2015), “success” rates are modest – 61 percent (Krisová, Žert and Žuffová 2015), and surgical complications significant – 21 percent (Baia et al. 2015).
Even more benign, so-called, “humane” collars2 effectively stop the horse from performing the adaptation he has created to cope with his challenging environment, and thus impose ever greater and eventually insurmountable welfare challenges.
A further difficulty in increasing the overlap in the Equine Prisoner’s Model is recognising when we have succeeded in providing that elusive space where adaptations and challenges correspond. There is a default assumption that horses are happy when there are no obvious indicators to the contrary. However, there is evidence that industry professionals and owners often misinterpret, or miss entirely, many behavioural indicators of equine distress (e.g. Lesimple and Hausberger 2014).
In a study of 373 horses from 26 riding schools, Lesimple and Hausberger (2014) found large discrepancies between what caretakers reported about the horses in their care (5 percent stereotypy prevalence) and what researchers observed in the stable (37 percent prevalence). The discrepancy was evident for milder stereotypies, and for more maladaptive and obvious stereotypies (researchers observed 23 percent of horses weaving, but only 8 percent were identified by caretakers). Greater exposure to stereotypies exacerbated this effect. In the stable where stereotypies reached 70 percent, the discrepancy between caretaker reports and objective researcher measurements was the greatest. Lesimple and Hausberger (2014) note that caretakers’ consistent underestimation of these poor-welfare indicators mirrors that found in nurses and doctors who tend to underestimate the severity of patients’ pain (as do Hirsh, Callandar and Robinson 2011; Lidén et al. 2012). Prolonged exposure to large populations of suffering individuals presumably distorts healthcare professionals and horse caretakers’ perceptions of “normal” behaviours and expressions.
Horses’ propensity to suffer silently (might we call it stoicism?) further complicates the task of ensuring their wellbeing. Yarnell, Hall and Billet (2013) found that horses undergoing an abbreviated, 10-minute “sham”3 clipping, mimicking an actual clipping procedure but with clipping blades removed, experienced significant physiological stress (higher cortisol levels, elevated heart rate etc.), regardless of whether they had been categorised as “compliant” or “non-compliant” based on their previous clipping history. The authors suggest that compliant horses may suppress flight responses when escape is not possible, leading to adverse physiological health and the development of abnormal behaviours – in short, a state of “learned helplessness”.
Learned helplessness occurs when horses (like other animals, including humans) face prolonged inescapable stress, and passively resign themselves to their dire circumstances even when an escape route has been reintroduced (Seligman, Maier and Geer 1968). Hall and colleagues (2008) suggest that learned helplessness is a logical adaptation; when behaviour has no impact on consequences, there ceases to be any motivation to trial novel strategies. This passivity becomes maladaptive because it generalises to other aspects of horses’ behavioural repertoire, and results in negative manifestations such as ulcers, weight loss and stereotypic behaviour.
What trainers may mistake as obedience and successful training may more likely represent a horse who has given up trying to escape from inescapable, conflicting pressure. When the equine discipline requires a flat affect such as western pleasure horses, show hunters, or “bomb proof” school horses, a state of learned helplessness is often considered not only normal, but desirable.
Almost all research agrees that preventing stereotypies initially is far more effective than trying to eradicate them once they become established (e.g. Luescher et al. 1991). Over time, stereotypies become emancipated from the original stressor, requiring little cognitive processing or need for sensory feedback. They are said to have moved into “central control” where they are triggered more readily, performed in more diverse situations and are more resistant to modification (Hothersall and Casey 2012; Mason and Latham 2004).
Although these “scars of the past” (Mason and Latham 2004, 563) will likely persist in spite of enrichment modifications, a failure to reduce or eliminate stereotypies should not be interpreted as a failure to improve welfare. Welfare may still be substantially enhanced through a variety of alternative management practices, both for horses with existing stereotypies and their compliant, non-stereotypic, but potentially more compromised, neighbours.
Although free pasture access remains the gold standard, alternatives are available to satisfy feeding motivation that may be more realistically provided in sport horse boarding facilities. The industry standard of providing the richest, finest quality hay may not be in the best interests of the horse (Cooper and Albentosa 2005; Mazzola et al. 2016; McGreevy et al. 1995a). For sport horses with higher energy needs, some high quality hay may be necessary, but can be supplemented with higher-fiber (less delicious) hay that will allow horses to eat for longer periods, and satisfy foraging needs without contributing to obesity (Davidson and Harris 2002). Forage consumption can also be slowed with the use of small-holed hay nets, doubling and tripling up small-holed hay nets (Ellis et al. 2015b), mangers with difficult access, spreading hay thinly over a larger area (Davidson and Harris 2002), or placing several hay nets in multiple locations (Ellis et al. 2015a).
Providing a variety of forage choices at multiple feeding stations also slows consumption, more closely mimics natural grazing and thus enriches the environment of stabled horses (Goodwin, Davidson and Harris 2002; Davidson and Harris 2002; Thorne et al. 2005). Goodwin et al. (2002) note that when given a choice of multiple forages, horses always consumed their less preferred forage along with their preferred forage. The authors suggest that the flexibility to selectively graze on a variety of available forages likely evolved as an adaptation that allowed horses to meet their energy requirements from whatever scarce resources were available (see also Thorne et al. 2005).
For sport horses competing in demanding disciplines, forage generally needs to be supplemented with high protein concentrates (oats, corn, pelleted grains etc.). However, palatable grains seem to be involved in the complex relationship between stereotypies and endogenous opiates, both of which promote dopamine production and seem to exacerbate stereotypies, particularly cribbing (Wickens and Heleski 2010).
As with forage, making horses work harder to access their grain (e.g. adding chaff to concentrates, placing smooth large stones in the bottom of the feeding tub, or using foraging devices that allow small amounts of food to fall out of a rolling ball or barrel) increase feeding time and encourage foraging behaviour (Malpass and Weigler 1994; Winskill, Waran and Young 1996). Mazzola and colleagues trained cribbers and matched controls to use a food dispenser (Quaryka ®) where horses activated a wheel to deliver small amounts of concentrates. Quaryka ® increased the time spent feeding for both cribbers and non-cribbers, and cribbers showed a significant reduction of their cribbing behaviour. Although cribbing “rebounded” to pre-intervention levels when Quaryka® was removed, the authors note that the 15-day intervention may have been insufficient to impact cribbing behaviour over the long term (Mazzola et al. 2016).
Interestingly, simply increasing meal frequency of concentrates does not necessarily reduce stereotypic behaviour, and in some cases exacerbates it. From survey data from 622 Swiss performance horse stables and 2341 horses, Bachmann, Audige and Stauffacher (2003) found that feeding four times per day increased the likelihood of stereotypic activity, compared with horses fed less or more often (see also McGreevy et al. 1995a). Horses fed less often may have experienced less emotional stress, having had fewer opportunities to anticipate food, whereas horses fed more often were presumably more satiated and less likely to perform anticipatory behaviours. Cooper et al. (2005) also found that increasing meal frequency increased locomotor stereotypic behaviour (weaving and head nodding), but decreased oral stereotypies (such as cribbing). As horses learned the new schedule, anticipatory weaving and head nodding peaked around feeding, and these behaviours were subsequently reinforced with food. Not surprisingly, horses not being fed while other horses were, or while feeding cues were present, also increased stereotypic behaviour.
Cooper’s group discussed the advantages of feeding free-choice forage, as satiated horses are less easily aroused when grain concentrates are being fed. Forage may also reduce cribbing duration and intensity by reducing gastric pain and making the horse’s need to crib less urgent (2005). Clearly, there is value in exploring the motivation behind stereotypical behaviour. Differing underlying motivations will not be universally ameliorated by a one-size-fits-all solution. Additionally, overall stereotypic activity may increase unless feeding schedule modifications are universally applied.
Group or paired turn-out reduces stereotypies, improves welfare, reduces housing costs and may not be as radical as it is currently perceived (van Dierendonck 2009; Keeling et al. 2016; Ladewig 2013). Contrary to popular wisdom, in stable herds aggression is rare, and almost never results in injury (Hartmann, Christensen and Keeling 2009; Hartmann, Keeling and Rundgren 2011; Heitor, Oom and Vicente 2006; Keeling et al. 2016; Ladewig 2013). Horses living in a natural herd form clear dominance hierarchies that serve to minimise aggression rather than exacerbate it. In an established herd of Sorraia horses, Heitor’s (2006) group found that dominance relationships were clear, linear and seldom contested. Even after the introduction of a breeding stallion, dominance ranks remained stable and served to keep aggression to a minimum. As Heitor and collegues explain, once ranks have been established, a dominant horse who wants access to a resource need only threaten a subordinate, who in turn avoids or acquiesces. Similarly, in 46 tests of introducing new horses to residents in various conditions of pre-exposure, Hartman and colleagues observed only one incidence of actual body contact, and the resulting injury was minor (2009).
Cozzi et al. (2010) demonstrated that horses are also unlikely to stay angry after aggressive encounters. In horses living in a stable social group, 86 percent of conflicts were followed by a friendly reunion between the opponents within 10 minutes after conflict. Reconciliations involving a third horse were even more likely. Third horses acted both as appeasers (initiating friendly contact with the aggressor), or consolers (initiating friendly contact with the victim). Cozzi proposes that these triadic interactions may provide a critical social mechanism for conflict resolution and the maintenance of social cohesion.
Recommended strategies for successful and peaceable group or paired turn-out include:
Where owners are still not convinced about group or paired turn-out, singly housed horses may still benefit from stable designs that allow tactile contact (e.g. grilled windows between stalls, half walls, or half wood/half grill walls). Cooper and colleagues (2000) eliminated weaving in a group of chronic weavers when the horses were housed in stalls that were open on all sides, allowing them to interact with compatible neighbours (see also Hothersall and Casey 2012; Dezfouli et al. 2014). In modern stable designs where stalls are separated with floor to ceiling wooden planks, gradually removing the upper planks so that eventually horses can put their heads into their neighbours stall is a cost effective way to increase interaction (see Figure 11.2).
Mirrors have demonstrated a moderating effect on some stereotypies (McAffee, Mills and Cooper 2002; Mills and Davenport 2002). In a group of six chronic weavers and head shakers, McAffee and colleagues found that the installation of an acrylic mirror eliminated these stereotypies entirely, along with other undesirable behaviours such as head nodding and aggressive head threats. The effect lasted over the study’s 5-week duration, even when the horses transitioned to a winter schedule of very limited turn-out. There appeared to be no “rebound effect” (i.e. an increase in motivation to perform the stereotypy once the intervention had ceased). Horses may interpret the mirror image as a new friend, enjoy the increased visual horizons or stimulation that the mirror provides or a combination of these factors. Arguably, the low cost, easy installation and portability make mirrors an environmental enrichment worth pursuing for horses that have limited equine contact.
Weaning places youngsters at high risk of developing stereotypies (see Figure 11.3). Good management for youngsters means “less management” – less weaning interference, less confinement and less grain (Wickens and Heleski 2010). In a study of breeding farms in North America, Europe and Australia “natural weaning,” where mares weaned the foals themselves, was associated with a decreased incidence of stereotypies in the foals (Parker et al. 2008). Confinement, even part-time, makes weanlings much more likely to develop stereotypies than those living in paddocks or pasture (Heleski et al. 2002; Waters et al. 2002; Parker et al. 2008). Feeding concentrates to weanlings is also problematic. Foals fed concentrates after weaning have been reported to be four times more likely to become cribbers than those who are not (Waters et al. 2002).
A plethora of research evidence points to the futility and cruelty of attempting to prevent stereotypic horses from engaging in their abnormal behaviours (e.g. Briefer Freymond et al. 2015; Mason and Latham 2004). For confirmed, chronic cribbers a practical, humane and realistic solution is to provide them with a place where they can crib safely without destroying their surroundings (Henderson 2007; Marsden 2002). A metal u-shaped bar, fitted with PVC piping, that reduces tooth wear and stall damage, provides a very satisfactory cribbing station for a committed cribber. It can be permanently mounted around an automatic water bowl (often a preferred, and disastrous, cribbing site – see Figure 11.4).
Alternatively, or additionally, a cribbing station mounted solidly on a plywood board that can be removed, transported and reinstalled in a horse show stall provides a welcome security blanket for a showing cribber on the road (Henderson 2007) (see Figure 11.5).
Horses are hard-wired to form social bonds. When other horses are not available, they will make do with other species, including donkeys, goats, dogs, cats and humans. As Budiansky (1997, 84–85) comments,
our horses’ affection for us, their owners, is unquestionably real, grounded in a basic instinct to form friendship bonds; it is slightly bruising to our egos, though, to realize that they bond with us only for lack of better company.
In herd living, allogrooming, the mutual, synchronous, nibbling around the withers and neck observed between pairs of horses, plays an integral role in establishing, maintaining and strengthening pair bonds, and herd mates generally have one or two preferred and enduring allogrooming conspecifics (Budiansky 1997; see Figure 11.6). Allogrooming has been associated with physiological effects of stress reduction, including lowered heart rate, blood pressure and cortisol levels; increased immunity; and a rise in beta endorphins (Feh and de Mazières 1993; Normando et al. 2003). Vigorous wither grooming by humans appears to have similar stress reduction effects for horses (Feh and de Mazières 1993), and may have similar bonding properties (McLean et al. 2013). Although it has not been tested, I would argue that it may also have similar calming and bonding properties for the human groomer!
Given the disparity between sport horses as they have evolved (Circle A) and the environmental challenges that we have asked of them (Circle B), it is remarkable that there is any overlap between these two circles. Arguably, this correspondence exists because the horse, for the most part, is the quintessential “nice-guy”. Unless we have done something to shatter their trust, most horses are affable, imminently social and extraordinarily adaptable (dare I say generous) in their efforts to cope with the taxing environments we have created for them. As Budiansky comments:
What we are exploiting in our relationship with horses is a well-developed set of equine behaviors, developed within the context of the equine social structure…. It is the [horse’s] innate social behavior that provides the raw material we of necessity must work with: this is the basis for the bonding and subordination that makes learning even possible.
(1997, 81)
Horses’ intensely social nature is both the quality that defines them and that which we have exploited to use for our sport and pleasure. It is such a travesty then, that we take these social beings, whose survival for millennium has depended upon the stability and cohesion of their social structures, and destine them to a life of solitary confinement.
Competitive riders face the unpleasant reality that they will always make greater demands on their horses than their horses would ever make on themselves. There is some comfort in knowing that in return we offer them a lifestyle of rich resources that would never be afforded to them toughing it out on the range. Yet, given the choice of an hour in the dressage or jumping arena, or eating grass with their equine friends, our horses would not choose us. Horses do extraordinary things for us, often against their inherent nature, but it is unlikely that they do so out of a competitive spirit or a desire to work in partnership toward a common goal. The horse has come a long way into our world. They are forced to use their athleticism and their intellect to configure themselves into whatever version of a horse we have invented for them in each equine discipline.
Perhaps it is time that we embrace their needs – needs not so very different from their ancestors. In the Equine Prisoner’s Model we can expand the overlap by modifying the environmental challenges we have set out for our horses and thus create a better fit with their evolutionary adaptations. As Budiansky (1997, 2) comments, “we have all too often confused the horse’s willing nature in the company of man with its inherent nature”. By recognising the challenges horses face in the environment we have created and making minimal modifications, we can begin to give back to the horse a modest fraction of what the horse has provided for us.
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