Tutorial Articleeve 217 531..539 How Riding May Affect Welfare: What the Equine Veterinarian Needs to Know P

EQUINE VETERINARY EDUCATION / AE / OCTOBER 2011 531

Tutorial Articleeve_217 531..539 How riding may affect welfare: What the equine veterinarian needs to know P. McGreevy*, A. McLean†, P. Buckley‡, F. McConaghy§ and C. McLean¶ Faculty of Veterinary Science (B19), University of Sydney, New South Wales; †Australian Equine Behaviour Centre, Victoria; ‡Charles Sturt University, Wagga Wagga, New South Wales; §Nature Vet, New South Wales; and ¶Central Highlands Veterinary Group, Victoria, Australia.

Keywords: horse; welfare; equitation; learning theory; performance

Summary (McGreevy 2007). Horses are highly adaptable and tolerant to human interventions. Indeed this characteristic Veterinarians generally focus on keeping the performance behavioural flexibility in horses makes them vulnerable to horse in work but they need to be mindful of ways in which welfare insults (McGreevy 2004). For veterinarians, the the work itself may jeopardise the animal’s welfare and increase in popular understanding of horse behaviour is health. Elements of a horse’s work may expose it to the risk having at least 2 effects: owners expect practitioners to of injury but insults to wellbeing, which are far more show best practice when handling their horses, and common and far more sustained, although less overt, also veterinary science, as the learned profession in horse care, deserve consideration. A good example is the way in must adopt a scholarly approach to emerging information which chronic physiological stress responses arising from that affects horse wellbeing. inhumane training techniques may compromise immunity This article is intended to address the need for and tissue repair. This article explores the physiological veterinarians to take an holistic view of their patient’s and musculoskeletal insults that can result from ridden umwelt. As Derksen and Clayton (2007) emphasise, “the work, alongside the gear and training paradigms that can challenge to equine veterinarians is that they become part compromise welfare. It also considers issues relating to the of a multidisciplinary team of scientists and equine use of pharmaceuticals in the ridden horse. With stress professionals devoted to finding ways to train elite horses reduction as a primary focus, it emerges that veterinarians and riders that will produce top competitive are uniquely placed to comment on the somatic effects of performances, while minimising injury and maximising psychological stressors, including the social and horse happiness”. ethological challenges resulting from the work required of Poor equitation can affect behaviour (such as attitude the so-called elite equine athlete. Whether the profession to work and response to signals), musculoskeletal health will step up to meet this significant challenge is also and gait biomechanics. Equitation science helps discussed. veterinarians to be more effective in preventing disease and injuries to horses and recommending effective, Introduction evidence-based therapy and rehabilitation of affected horses thereby improving sporthorse wellbeing. The current Like all animals, horses learn most effectively when training article tackles the broad issue of ridden horse welfare using methods are appropriately aligned with learning processes the following framework: and abilities. In addition to ineffective learning, inappropriate training practices can also have a negative 1. Physiological insults resulting from ridden work, impact on a horse’s welfare and can lead to conflict 2. Musculoskeletal insults resulting from ridden work, behaviours (for example bucking, rearing, bolting, etc.) 3. Issues relating to the use of pharmaceuticals in the that jeopardise the safety of riders, handlers and the horses ridden horse, themselves. Equitation science - the science of horse 4. Gear that can compromise welfare, training and riding - gives us a way of measuring and 5. Training paradigms that can compromise welfare, interpreting interactions between horses and their riders 6. Social and ethological challenges resulting from ridden work, *Corresponding author email: [email protected] 7. The elite equine athlete.

1. Physiological insults resulting from one study of Australian Pony Club animals (Buckley 2009). It ridden work has been suggested that lameness is often mediated through problems originating in the horse’s back The physiological challenges of ridden work reflect the (Landmann et al. 2004) that manifests as asymmetrical mismatch between the horse’s evolution and human loading through a given limb. By the same token, taller and requirements. It is generally only in cross-country and heavier horses may be characterised by longer thoracic endurance trials that veterinarians expect to examine vertebral columns and ventral curvature of the thoracic significant numbers of exhausted horses. However, vertebral column (Johnston et al. 2002). A longer vertebral subclinical issues associated with compromised nutrition, column can result in greater lateral/axial bending of the hydration and exercise affect the physiology of horses caudal vertebral column and may predispose this region during transit to competition or training and can even to injuries (Johnston et al. 2002). characterise some types of stable management. Deleterious effects of ridden work on hydration and Risk factors for sore backs acid-base balance are dealt with exhaustively elsewhere in the veterinary literature and so will not be considered in When Van Weeren and Crevier-Denoix (2006) explored the detail here. Other than being pushed beyond role of equine conformation in maintaining soundness, physiological limits, potential problem areas include they found very little supportive evidence and much overfeeding that creates the need for fatiguing lungeing conflicting data. For objective evaluations to proceed in regimes prior to ridden work (McGreevy and McLean the future, they suggested that conformation needs to be 2010), feeding of discrete meals that cause fluctuations in standardised and epidemiological studies must provide gastric acidity (McGreevy et al. 1995) and therefore data on injury occurrence. Johnston et al. (2002) found challenge acid-base homeostasis; excessive periods that back conformation and horse height affected the without feed and water that may compromise circulating movement of the vertebral column. Further significant risk blood volumes (Evans 2002), underestimating stress of factors in an epidemiological study of sore backs include transporting horses (Weeks et al. 2011), insufficient recovery exercise frequency, confinement (stabling), conformation, days after exercise (Evans 2002) and lack of adequate and body condition score and breed (Buckley 2009). inappropriate warming-up (McGreevy and McLean 2010). At pasture, horses spend most of their day with their heads down close to the ground, grazing and moving 2. Musculoskeletal insults resulting from (McGreevy 2004). There are data to demonstrate that ridden work stabling increases the risk of sore backs (Buckley 2009), perhaps as a result of inactivity or postural effects. The postural benefits of grazing at pasture may include Occurrence of musculoskeletal injury in prolonged lowering of the head that results in stretching horse populations the soft tissues along the horse’s dorsum. It has been suggested that extended periods of soft tissue shortening in Lameness has been widely documented as one of the the tendons and ligaments of the equine lower limb may most common health problems in domestic horses (Ross compromise effective conditioning of horses for exercise and Kaneene 1996; USDA 2001; Buckley 2009) and one of leading to a greater risk of injury (Goodship and Birch the leading causes of wastage among racehorses (Bailey 2001). The association between intermittent exercise and 1998; Perkins 2005; Parkin 2006). It is certainly not confined the incidence of sore backs reported by Buckley (2009) to disorders of the limbs since sore backs have been may result in horses being physically underprepared reported as among the most commonly diagnosed for competition and subsequently at higher risk of disease events in a longitudinal study of Pony Club horses in orthopaedic injury. Merely by being ridden, horses are Australia (Buckley 2009). challenged to perform at a higher or more sustained level Prevalence and incidence of musculoskeletal injuries than their wild counterparts (Goodship and Birch 2001). vary with population sampled. For example, among the Their work manifests as more movement of the back, general populations of horses, reports varied from a predisposing to orthopaedic injury (Goodship and Birch seasonal prevalence of 3.4% (USDA 2001) to a monthly 2001). incidence of 7.2% in Michigan State horses (Ross and Kaneene 1996) whereas, among Australian Pony Club Relationship between lameness and sore backs horses, the monthly prevalence of lameness was as high as 50% and monthly incidence as high as 27% (Buckley 2009). Associations between back problems and concurrent lameness have been reported in a population of horses Risk factors for lameness that presented with orthopaedic problems (Landmann et al. 2004). More back problems were detected in lame Horse size can increase the risk of lameness, with dressage horses than in the control group (horses with Thoroughbreds being at higher risk than pony breeds in similar breeding examined as part of a prepurchase

examination). It was reasoned that the resultant atypical with trauma, but these agents can also mask lameness. loading of the vertebral column that results from lameness Masking lameness may obstruct or delay a diagnosis and may contribute to the development of chronic back may force a horse to undertake work that accumulates injuries. additional damage to inflamed or injured tissues There is evidence that horse owners/riders need expert (McGreevy 2004). Nonsteroidal anti-inflammatory drugs assistance with the early detection of musculoskeletal also have the potential to have adverse side effects, injury. In one study, owners diagnosed lameness and sore including gastric ulceration and renal damage. For this backs in only 23 of the 202 lamenesses detected by a reason the FEI has resolved to disallow them in veterinarian, and only 11 of the 236 sore backs detected competition, but allow post competition usage of certain by a veterinarian (Buckley 2009). NSAIDs (FEI 2010). Intra-articular corticosteroids are also routinely used in the management of arthritis and, while Prevention some of these agents, including triamcinolone, have been shown to be beneficial to articular cartilage, overuse of While lameness and sore backs among ridden horses are these medications can result in cartilage damage (Trotter common, they are probably largely avoidable (Denoix 1996). Veterinarians must be aware of the possibility of and Pailloux 1997). Beyond the risk factors discussed abuse of these therapeutic agents, especially those that above, experts in equine locomotion and biomechanics they themselves may have prescribed and advise horse have emphasised the importance of an ideal rider-horse owners that horses requiring these agents need combination (Denoix and Pailloux 1997). The right appropriate rest and rehabilitation before returning to combination helps the horse cope with a weight on its exercise. back and the added physical demands of equestrian Sedatives and tranquilisers can be used in founda- endeavours, through thoracic, thoraco-lumbar and tion training, retraining and performance contexts lumbo-sacral flexion, concentric contraction of (McGreevy 2004) and agents that mask pain may abdominal muscles and of the long muscles of the neck transiently reduce the risk of pain-related misbehaviour. (Denoix and Pailloux 1997). A horse appropriately Tranquilisers commonly used in ridden horses include conditioned and trained to carry riders correctly, is likely acepromazine and reserpine. The effects of these to avoid many of the injuries that may otherwise be agents on the nervous system include depression of sustained. This underlines the need for more education of movement and complex behaviour (Dyke 1993). owners in appropriate musculoskeletal and behavioural Reserpine can result in adverse side effects, including conditioning (McGreevy 2004) as well as equine hypotension, bradycardia, colic, diarrhoea and penile biomechanics (Denoix and Pailloux 1997). Thoracolumbar relaxation (Tobin 1978). When horses are trained while disease in equine patients is complex and data on cause sedated, there is no chance of the horse learning to and prevention are incomplete. Additional factors likely behave appropriately when the medication is removed. to be involved in the soundness of horses’ backs are Veterinarians need to show leadership in emphasising this saddle fit (Haussler and Erb 2006), the horse-rider critical point to clients. compatibility and rider skills (Denoix and Pailloux 1997). In summary, it is reasonable for riders to expect equine 4. Gear that can compromise welfare veterinarians to be competent in assessing risks for orthopaedic injury, including lameness and sore backs. To The following discussion of equipment in horse training achieve this, equine practitioners must ensure that their assumes that the reader is conversant with learning theory knowledge and skills include an understanding of (for review see McGreevy and McLean 2007). Any piece of conformation, saddle fit, equitation skills and gear can be used inhumanely, so problems with certain musculoskeletal and behavioural conditioning. items of apparatus generally reflect problems with the operator. Veterinarians are challenged in making 3. Issues relating to the use of recommendations about tack because of the dearth of pharmaceuticals in the ridden horse scientific evidence on the effects on horse health, performance and welfare. It is recognised that pharmaceuticals can be used as Welfare can be compromised by restriction of natural masking agents to disguise unacceptable responses and movement and excessive pressure from apparatus. enhance performance. The most important conditions Pressure is a function of area (e.g. kg/m/s), so with any that relate to welfare in the ridden horse are lameness piece of tack, the broader the area that makes contact and dangerous locomotory responses. Nonsteroidal with the horse, the less discomfort it causes and the less anti-inflammatory drugs (NSAIDs), such as phenylbutazone, rewarding its removal is. In essence, all pressure-based ketoprofen, salicylic acid and flunixin meglumine, are used training places the horse in a discriminatory dilemma. The routinely in equine practice as these products have animal must respond to some pressures (e.g. from the bit) therapeutic benefits in reducing inflammation associated but habituate to others (e.g. from the girth).

Saddles, treeless saddles, saddle pads, girths, (especially if they touch only in small areas, as in the case cinches and surcingles of thin, bladed and twisted bits). Unrelenting pressure from a bit can prompt a horse to The horse’s back moves by rotation, flexion, extension and trial evasions (McLean and McGreevy 2010a). Unorthodox lateroflexion (Denoix and Pailloux 1997) during locomotion. bits apply pressure with greater severity or to different parts A saddle supports the rider’s position and distributes the of the mouth. Although they can, and sometimes do, sever rider’s weight across the musculature on either side of the the tongue (Rollin 2000), saw chain bits (so-called mule bits horse’s thoracic midline. The tree within a conventional and correction bits) are readily available to riders having saddle prevents the rider’s weight from pinching the problems getting horses to respond to milder bits. The horse’s back. Flexible and adjustable trees are becoming escalation of force operating in this paradigm is entirely popular among riders acknowledging that movement contraindicated. restrictions caused by tack should be minimised for optimal In some equestrian cultures, hackamores and bosals performance and maximal comfort. Straps to prevent are the preferred means of controlling the head; in others saddles from slipping include girths around the thorax, they are used more often when traditional bits have surcingles for both saddle and thorax, cinches or cinch proved ineffective. If changing or increasing mouth straps for the abdomen, breast-plates for the base of the pressure is unsuccessful, riders and trainers may resort to an neck and pectoral region and cruppers for the tail-head. If alternative or additional means of making the horse adopt any of these are inappropriately loose or tight or in contact the desired posture by applying pressure to other parts of with damaged or highly sensitised tissue, the horse may be the head (McLean and McGreevy 2010b). Typically other prompted to produce a counter-predator response ‘training’ devices employed include curb chains, gags, (McGreevy and McLean 2010). For girths specifically, it is draw reins, balancing reins and chambons. Such devices recognised that overtightening can compromise thoracic generally use first class levers that amplify the tension on excursions and thus affect athletic performance (Bowers the rein as a result of their lever action and so can create and Slocombe 2005). Unfortunately, scientific evidence for a misleading impression of mildness. The length of the correct saddle fit criteria is lacking. However, the fit of the shank magnifies the leverage through the bit. saddle can be assessed using the method described by Unfortunately, the tendency is to develop a reliance on Harman (1999) that aims to distribute the pressure beneath these extra pulleys, rather than to use them solely for the saddle in a fairly uniform pattern over the panels retraining. without areas of localised high pressure. Horses that fight or ignore pressure cues are often subjected to increased pressure via mechanical restraints Bits and nosebands and stimulants (McLean and McGreevy 2010b). However, horses rapidly habituate to aversive stimuli, so reaching for Biomechanically, bits allow riders to either direct pressure more severe bits is ill advised and may only lead to further on the tongue and bars (snaffle and curb bits) or pressure desensitisation. via leverage through shanks attached to the bit The need in some equestrian sports to use strong (McGreevy and McLean 2010). The horse’s mouth never pressure on horses so that they adopt an ‘outline’ and evolved to accommodate a bit, let alone 2. It is make them work ‘on the bit’, can prompt trainers to use remarkable that at the highest levels of dressage, the use stronger bits as their first approach to achieving what is of a double bridle remains mandatory. When the tongue is known as direct (or vertical) flexion (McGreevy et al. 2010). depressed by a bit, it does not fit in the narrow In contrast, enlightened trainers have known for centuries intermandibular space, so the tongue is regularly pressed that the ‘on the bit’ outline is an emergent property of against the bars of the mouth (McGreevy and McLean correct basic responses, in particular when locomotory 2010). Fluoroscopic studies show that the bit rests on the responses are under stimulus control. tongue, rather than on the bars of the mouth, as was When horses open their mouths to escape the bit originally believed (Clayton 2005). The tongue normally fills pressure, one short-term response by riders and trainers is to the oral cavity, so the bit sits on it but can easily press up on use a noseband that keeps the mouth tightly closed the bony, hard palate. Certain types of bits may be (McGreevy 2010). Evidence to support the benefits of such associated with a reduction in swallowing frequency nosebands is lacking although anecdotal evidence (Manfredi et al. 2005), possibly by restricting the suggests that rein responses are lighter when the ridden movements of the tongue necessary in deglutition. The horse’s mouth is kept tightly closed. A similar criticism can same is likely with restrictive nosebands that effectively be levelled at tongue ties since they restrict normal function as jaw-clamps. movement of the tongue, such as during swallowing, and Horses can be easily trained to pull against harnesses, also stop the horse from finding comfort. However, there breast plates and collars in contact with well muscled is some evidence of tongue ties improving racing areas, such as the shoulders and pectoral regions, but performance in selected Thoroughbred racehorses common sense suggests that they are generally reluctant (Franklin et al. 2002; Barakzai et al. 2009). The putative to habituate to strong pressure from bits in the mouth benefits are probably in ameliorating the effects of oral

conflicts that have arisen from dysfunctions in negative presence of the bit requires the tongue to move into a reinforcement of correct stop/slow responses. As more-or-less abnormal position plus there is a need in some equestrian sports became more popular and competitive equestrian disciplines to maintain rein contact, sharp in the 1970s, dropped nosebands gave way to elements of the horse’s dental arcade may damage its Hanoverian, crossover and grackle nosebands. Then, in the cheeks and tongue. The result can manifest as bit 1980s, ‘crank’ nosebands emerged. These have a dubious avoidance or habituation. In effect, the horse can added feature: they can be tightened much further than become more difficult to maintain in speed, line and regular nosebands due to a lever action. This seems to posture. sensitise the horse’s mouth, making the horse much more Mouth pain may also be associated with responsive to rein pressure and, to some, this gives the heavy-handed riding or inappropriate gear. For example, appearance of the horse becoming more ‘submissive’. some jointed bits can cause pinching between the second The breadth of the bit that has contact with the premolar and the labial commissures (McGreevy 2004). mouth (or other part of the head) and the action of any Wolf teeth, especially those with loose roots and cusps that levers will also affect the way rein tension is translated to are directed towards the seat of the bit, may trigger the the horse. Bitless bridles may be an effective alternative horse to reef the reins out of the rider’s hands or avoid it by to traditional bridles and may avoid some horses shortening its neck. This can rapidly escalate into head acquiring oral conflicts (Cook and Mills 2009). However, tossing which is reinforcing (McGreevy 2004). In the event bitless bridles are not necessarily a panacea for horses of a horse fighting the bit, some veterinarians and equine since they also rely on negative reinforcement (and dental technicians are prepared to remove an therefore the horse’s motivation to remove the pressure) appreciable portion of the second premolar to create a as much as any bitted bridle so they are only as good as ‘bit seat’ or ‘cheek seat’, which is supposed to improve the hands at the other end of the reins. Furthermore, comfort in this part of the mouth (Wilewski and Rubin 1999). bitless bridles may sometimes lack the ability to deliver While one study reported improved athletic performance the clear lateral pressure needed for turns, tending in most horses after the creation of bit seats (Wilewski and instead to tighten on the horse’s head before effecting a Rubin 1999), an abiding question is whether a simple turn. It is, therefore, important that when equitation change of riding technique or bit (e.g. to an unjointed scientists report studies of rein tension, they must specify design) would have been equally effective. the dimension and design of the gear used. Whips and spurs Martingales and tie-downs If a horse fails to show sufficient forward movement or There is a dearth of science around the physiological and impulsion, trainers often direct their attention to the sides, behavioural consequences of physical restraint in horses. where they can increase the pressure by using whips and That said, it is clear that martingales and tie-downs that spurs and more effectively send the horse forward apply pressure to the nasal planum via the noseband (in (McGreevy and McLean 2010). Although, for some, these the case of the standing martingale and tie-downs) or the stimulants are distasteful, they are not necessarily mouth via the reins (in the case of the running martingale contraindicated. They can be used minimally and with or draw reins) are designed to prevent evasive raising of accuracy to ensure consistency, and be employed the head (McGreevy and McLean 2010). The rider can use transiently to fortify the rider’s leg signals. In both cases, the lever action of the running martingale to pull the head they fortify only if the horse has a clear learned response to lower. Critics rightly point out that these gadgets force the either whip or spur, so it is efficient to train such responses in horse into an outline rather than train self-carriage through the absence of the rider’s leg pressures first. lightness. Rather, when the head is forced downwards, the muscles of the neck and topline are not ‘suspending’ the 5. Training paradigms that can head and neck but instead the horse is attempting to raise compromise welfare its head against aversive pressure (McGreevy et al. 2010). Gadgets that fix the head position deny the horse’s need Riders, handlers and veterinarians have a responsibility to to move its head forwards and backwards in the walk and minimise stress and conflict in the horses in their care. the canter, which consequently become affected. The Training techniques, both in-hand and under-saddle, have position of the head and neck of the horse are pivotal in a significant effect on a horse’s life during and after balance and so the effect of head and neck restraint on training sessions (McGreevy and McLean 2010). locomotion should not be underestimated (McGreevy and Inappropriate techniques cause confusion, conflict, flight McLean 2010). responses and musculoskeletal degeneration. This Dentition and mouth pain discussion deals primarily with training paradigms under-saddle. However, groundwork or training in-hand The horse’s comfort, especially when ridden, can be should be equally clear not least because it has profoundly affected by its dentition. Because the intraoral repercussions for responses shown under-saddle. It seems

that unclear responses to stimuli given in-hand will have a gauges applied to reins since it has been reported that deleterious effect on ridden work and that good judges and, presumably, arena stewards are unable to groundwork improves trained responses under-saddle reliably detect lightness of cues (de Cartier d’Yves and (McGreevy et al. 2009). The application of the principles of Ödberg 2005). learning theory to horse training will minimise the incidence The repeated inappropriate or ineffectual application of welfare issues and help to ensure that equitation is of a cue, such as a squeeze nudge or kick for ‘go’, without ethical (McGreevy and McLean 2007). The 8 principles of the desirable response being achieved, may result in best practice in horse training are as follows: desensitisation to the cue. Loss of proportionality of responsiveness is a byproduct of this training as well as the 1. Use learning theory appropriately, developments of conflict behaviours and the possibility of 2. Train easy to discriminate signals (to avoid confusion), learned helplessness. This can result in excessive use of 3. Train and shape responses singly (to avoid confusion), whips and spurs and the potential for bleeding rowel or 4. Train only one response per signal (to avoid confusion), spur injuries. 5. Responses to be completed within a consistent The practice of allowing one cue to cue multiple structure (to facilitate habit formation), responses can compromise welfare (McGreevy and 6. Train persistence of responses (self carriage ensures the Boakes 2007). For example, applying one rein only should absence of oversignalling), result in turn. The practice of using one rein for dramatic 7. Avoid and dissociate a flight response (because of its neck flexion laterally (aiming for increased submission or resistance to extinction and interference with slowing) may result in a weakening of the turn response learning), and ultimately some conflict (McGreevy and McLean 8. Benchmark relaxation (to ensure the absence of 2010). conflict). Other training paradigms that may cause welfare issues include the use of rapping in jumping, whereby the rail of a Ensuring that a horse is under the stimulus control of the jump is raised artificially to knock a horse’s legs as it jumps. rider and handlers helps to prevent dangerous responses The use of tissue irritants (such as in soring) to improve leg to extraneous or environmental stimuli. Responsiveness to carriage flamboyance is condemned but is notoriously external stimuli, rather than the handler, and consequent difficult to confirm. unruly or dangerous behaviour may be a cause for wastage (via culling for inappropriate behaviour) (Ödberg and Bouissou 1999). Where multiple responses exist for a 6. Social and ethological challenges single cue, the resultant cue/response relationship is resulting from ridden work unreliable or weakened (McGreevy and Boakes 2007). In-hand interactions may be elicited from cues such as Social and ethological challenges constitute any and all voice or body posture but they rely on operant elements of ridden work that represent a challenge to the conditioning that arises from tension in the lead rein or way in which horses have evolved to behave and run pressure from whip tapping. Resolving behaviour problems counter to its social preferences. in-hand therefore requires attention to the basic responses Being ridden is, in the strictest sense, an ethological trained via negative reinforcement. Pressures in the horse’s challenge, since horses have not evolved to be ridden any mouth and from the rider’s legs are the fundamental more than humans have evolved to ride them (McGreevy conduits for negative reinforcement in the ridden horse et al. 2009). After habituating to the saddle, girth and (McGreevy and McLean 2010) whereas postural cues and bridle, the horse being prepared for ridden work must then seat signals are classically conditioned elements. Therefore adapt to carrying a human. Equestrian dogma insists that rectifying problems under-saddle requires retraining of rein this brings with it some shift in the centre of mass of the and leg pressure signals primarily. Delivering 2 cues that dyad from the centre of mass of the horse alone, but apply contradictory pressures will decrease the clarity of recently this has been contested (see McGreevy et al. response to one or both cues. Most commonly this occurs 2009 [neck-flexing] for review). What is more certain is that when riders apply simultaneous rein and leg or spur, as a the horse must adapt to the sight, sound and feel of way of achieving flexion of the neck. Consequences of this another being on its back. More fundamental is the loss of may include deterioration of both the stop and the go control. Control of the locomotory responses is central to responses, hyperresponsive behaviour, such as pigrooting horse-human interactions so it is quite possible that horses, or bucking or, ultimately, learned helplessness that if given the choice, would prefer not to be ridden since this manifests as apathy. necessarily is accompanied by a loss of autonomy. The Relentless pressure on the bit from the rider’s rein to ethics of equitation are discussed elsewhere (Jones and achieve certain postures results in increased pressure on McGreevy 2010), but let us assume that the context in the tongue (Clayton 2005), in addition to decreasing the which the horse is working is justified in a cost benefit effectiveness of the primary cue to stop or slow. The extent analysis and that the horse is being ridden with the most of this pressure can be most effectively detected by strain subtle of cues.

For a prey species, loss of autonomy and having to pressures from the riders and an often terminal loss of approach aversive stimuli may be particularly disturbing. lightness in signalling (McGreevy and McLean 2010). The powerful tendency to flee may, on occasions, expose The more competitive a horse is in its performance, the deficits in the animal’s training or create conflict between more likely it will be to encounter frequent transport and the horse and the rider, sometimes leading to escalation in multiple novel environments. Most horses habituate to this the forces applied under a negative reinforcement flux but these changes can be accompanied by the paradigm and sometimes leading to punishment. The challenges of changes in fodder and drinking water, which need to vanquish avoidance strategies may also underpin may be refused by some horses (Welford et al. 1999) or equestrian techniques such as hyperflexion that reduce a even extended periods of food and water deprivation and ridden horse’s ability to conduct surveillance (McGreevy resultant health issues. Other challenges include transport et al. 2009). stress and risk of respiratory disease. These are dealt with in While free ranging horses have been known to jump some detail in an accompanying review of welfare issues obstacles in their path, especially when cantering or related to horse transport (Weeks et al. 2011). galloping, most horses circumnavigate obstacles if given the chance to do so. To leap onto unseen ground is inherently aversive and jumping itself is an energetically 7. The elite equine athlete expensive option. For these reasons, untrained horses are rarely seen jumping for the sheer joy of it. Although some Some horses compete at an elite level and are thus horses are sufficiently trained to jump obstacles without affected by unique pressures. They are typically stabled, their jockeys, this reflects their training and the herd effect exercised at least 6 times a week and entered in rather than equine joy at surmounting manmade competition approximately once every 1–2 weeks obstacles. In showjumping and cross-country, horses that (McGreevy 2004). They are regularly transported to habitually run (or even bolt) toward jumps have acquired competitions, mainly by road but sometimes by air. They some learned hyperreactivity and certainly are a danger frequently mix with unfamiliar horses at competitions. The to themselves (and their riders). Flight responses in the welfare concerns for these horses reflect the increased risk direction of hazards should not be confused with a of certain diseases that arise from regular travel and willingness to jump (McGreevy and McLean 2010). For this competition. Travel is associated with pleuropneumonia reason, correct technique in jumping horses requires the (travel sickness), while mixing with strange horses increases horse learning to maintain the speed set by the rider the risk of infectious diseases, such as viral respiratory tract (McGreevy and McLean 2010). disease. Leaving the home range can be problematic in Frequent, high intensity exercise will increase the risk youngsters but similar signs can also emerge in those with of horses developing degenerative joint disease and orthopaedic pain elicited by a transition from grass to overtraining syndrome (McGowan and Whitworth 2008). metalled surfaces (leaving the yard to commence Joint disease can occur acutely, due to an injury such as a roadwork) and manifests as unwillingness to go forward. twist or sprain, or chronically, due to mild but persistent The importance of equine ethology can never be trauma. Meanwhile, stabling and, specifically, feeding with overstated, especially when one considers social concentrated diets, significantly increases the risk of influences. Separation-related distress in the ridden context equine gastric ulcer syndrome (EGUS) (Bell et al. 2007). may manifest with the same failure to respond to ‘go’ Although inflammation is the body’s reaction to injury, signals but reflects the overshadowing of the ‘go forward’ the inflammatory process can, unfortunately, have response by a key attachment figure, usually a preferred damaging effects of its own. Inflammatory cells, the body’s field mate. Social influences of other horses may also defender cells, contain chemicals that can kill bacteria by trigger unwelcome forms of mimicry. For example, social breaking down the cell walls of bacteria, but these facilitation can precipitate ill judged flight responses in chemicals can also break down the body’s own cells. The ridden horses and tethered horses, both of which can result release of inflammatory cells into a joint can trigger the in traumatic injuries (McGreevy 2004). Such effects on release of enzymes that break down proteoglycans, both nearby horses are even thought to prompt premature hyaluronic acid in the joint fluid and chondroitin in the take-off in horses racing over jumps and hurdles, again with cartilage (Pool 1996). Any significant loss of hyaluronic acid the potential for trauma (McGreevy and McLean 2007). causes the joint fluid to lose its viscosity and ability to Multiple handlers and multiple riders may be a feature function as a lubricant. Loss of chondroitin from cartilage of horses that change hands frequently (including causes structural damage to the cartilage, which swells so-called problem horses) or those that are used in riding and loses its resilience. Thus, the joint cannot function schools. Their welfare can be compromised by inconsistent properly and normal weightbearing exercise causes training methods and inconsistent training signals with the further joint damage. result that the horses may fail to discriminate signals Elite horses are often trained for long periods and may correctly and may offer inappropriate responses, in effect suffer a syndrome known as ‘overtraining’. Overtraining is a becoming confused. This can lead to an escalation of significant cause of poor performance in both equine and

human athletes (McGowan and Whitworth 2008). It is not understanding of how horses learn and how they can best be well defined in horses but is characterised by a number trained ethically represents a powerful tool to veterinarians of symptoms, including weight loss, reduced exercise attempting to minimise such insults. Veterinarians should not capacity, reduced red blood cell volume (PCV), reduced assume when dealing with health issues that training is immune function, increased muscle enzymes, increased necessarily optimal even for the elite athlete as there are Gamma Glutamyl Transferase (GGT, a liver enzyme) and many entrenched techniques and methodologies that reduced markers of exercise capacity (McGowan and can directly lead to health compromises. Technological Whitworth 2008). Overtraining is well recognised in advances, such as cranked nosebands, may facilitate racehorses, being associated with poor performance, restraint without due regard for welfare. The application of weight loss, abnormal behaviour and in endurance horses clear signals and correct use of pressure and release should (Ridgway 1994), where poor appetite, dullness, lack of be used in training to avoid creating habituation to the same vigour, reduced performance and lengthy recovery pressure signals that are pivotal in subtle equitation. Rules periods are observed. A study of the behaviour of concerning the mandatory use of the double bridle and spurs overtrained horses reports differences in behavioural in higher levels of dressage merit further scrutiny. The bodies responsivity, indicating a form of mental stress or that govern horse sports must identify the types of scientific ‘psychological overload’ (De Graaf-Roelfsema 2007). evidence they require when considering the welfare Overtrained horses can also show abnormal endocrine implications of novel techniques and technological responses with reduced cortisol concentration after advances. maximal exercise, suggesting adrenal exhaustion (Hamlin It is clear that the health and welfare of elite horses are et al. 2002). compromised by many of the environmental factors that It has been reported that 90% of horses in active characterise intensive horse husbandry: being kept in training for racing have EGUS (Bell et al. 2007). When horses stables, regular, high intensity exercise, transport to are put into stables and fed only twice daily, there are long competitions and mixing with unfamiliar horses. intervals when the horse is not eating and the stomach is Veterinarians should encourage horse owners and riders to exposed to decreasing pH. Recent evidence has identified change their management practices to improve the that certain dietary components causing EGUS in nonrace health and welfare of horses in their care. horses are readily modifiable (Luthersson et al. 2009). Enlightened horsemanship recognises that the Management that might affect the normal balance of behavioural flexibility of the horse makes it vulnerable to mucosal protective factors and lead to ulceration include welfare insults. The horse appears to tolerate restraint in the amount of grain fed per day and per meal, feed ways that most other species would not. The veterinary deprivation for more than 6 h and water deprivation. profession can lead the way in encouraging owners and Lucerne hay is high in protein, which potentially has a riders to improve their horse training and handling practices buffering capacity and feeding lucerne hay and chaff to reduce suboptimal interventions. Improving horse health with grain may assist in preventing ulcers (Nadeau et al. and welfare will produce horses which are safer to handle, 2000). Exercise, particularly high intensity exercise, also perform better and are happier to perform. predisposes to ulcers because decreased stomach motility or increased pressure in the stomach increases exposure of Authors’ declaration of interests the nonglandular stomach lining to acid. Since the 1900s, it has been recognised that No conflicts of interest have been declared. transportation can cause pneumonia. However, the precise mechanisms have only been elucidated more recently References (Racklyeft et al. 2000). The most important predisposing Bailey, C.J. (1998) Wastage in the Australian Thoroughbred Racing factor for lower respiratory tract disease is restraint of the Industry. RIRDC Research Paper No. 98/52. horse such that it cannot lower its head and physically clear Barakzai, S.Z., Finnegan, C. and Boden, L.A. (2009) Effect of ‘tongue tie’ material from the airways (Racklyeft and Love 1990). use on racing performance of Thoroughbreds in the United Strenuous exercise results in contamination of the lower Kingdom. Equine vet. J. 41, 812-816. airways and exercise performed after transportation exerts Bell, R.J.W., Mogg, T.D. and Kingston, J.K. (2007) Equine gastric an added detrimental effect on the defence mechanisms ulcer syndrome in adult horses: a review. N. Z. vet. J. 55, 1-12. of the lower airway (Oikawa et al. 1995). Elite horses are Bowers, J. and Slocombe, R.F. (2005) Comparison of girth materials, girth tensions and their effects on performance in racehorses. Aust. vet. J. routinely transported to competitions on the day of the 83, 68-74. competition and are at significant risk of developing Buckley, P. (2009) Epidemiological Studies of Health and Performance transport induced pleuropneumonia or ‘travel sickness’. of Pony Club Horses. PhD thesis, University of Queensland, Australia. Take-home messages de Cartier d’Yves, A. and Ödberg, F.O. (2005) A preliminary study on the relation between subjectively assessing dressage performances and objective welfare parameters. In: Proceedings of the 1st Many of the insults to horse health, performance and International Equitation Science Symposium, Broadford, Victoria, welfare through riding are preventable or modifiable. An Eds: P. McGreevy, A. McLean, N. Waran, D. Goodwin and A.

Warren-Smith, Post-Graduate Foundation in Veterinary Science, McGreevy, P.D., Harman, A., McLean, A.N. and Hawson, L.A. (2010) Sydney. pp 89-110. Over-flexing the horse’s neck: a modern equestrian obsession? J. Clayton, H.M. (2005) Bitting: The Inside Story. USDF Connection, vet. Behav. clin. appl. Res. 5, 180-186. December, 28-32. McGreevy, P.D. and McLean, A.N. (2007) The roles of learning theory and ethology in equitation. J. vet. Behav. clin. appl. Res. 2, 108-118. Cook, W.R. and Mills, D.S. (2009) Preliminary study of jointed snaffle vs. crossunder bitless bridles: Quantified comparison of behaviour in McGreevy, P.D. and McLean, A.N. (2010) Equitation Science, four horses. Equine vet. J. 41, 827-830. Wiley-Blackwell, Oxon. De Graaf-Roelfsema, E. (2007) Endocrinological and Behavioural McGreevy, P.D., Oddie, C., Burton, F.L. and McLean, A.N. (2009) The Adaptations to Experimentally Induced Physical Stress in Horses. horse-human dyad: can we align horse training and handling Dissertation Utrecht University, Faculty of Veterinary Medicine. activities with the equid social ethogram? Vet. J. 181, 12-18. McLean, A.N. and McGreevy, P.D. (2010a) Horse-training techniques Denoix, J.-M. and Pailloux, J.-P. (1997) Physical Therapy and Massage for that may defy the principles of learning theory. J. vet. Behav. clin. the Horse, Manson Publishing, London. appl. Res. 5, 187-195. Derksen, F.J. and Clayton, H.M. (2007) Is equitation science important to McLean, A.N. and McGreevy, P.D. (2010b) Ethical equitation: capping veterinarians? Vet. J. 174, 452-453. the price horses pay for human glory. J. vet. Behav. clin. appl. Res. Dyke, T. (1993) Sedatives, tranquilisers and stimulants. In: Drug Use in 5, 203-209. Performance Horses, Eds: K.W. Hinchcliff and R.A. Sams, W.B. Nadeau, J.A., Andrews, F.M., Mathew, A.G., Argenzio, R.A., Blackford, Saunders, Philadelphia. pp 621-635. J.T., Sohtell, M. and Saxton, A.M. (2000) Evaluation of diet as a cause Evans, D.L. (2002) Welfare of the racehorse during exercise training and of gastric ulcers in horses. Am. J. vet. Res. 61, 784-790. racing. In: The Welfare of the Horse, Ed: N. Waran, Kluwer Academic Ödberg, F.O. and Bouissou, M.-F. (1999) The development of Press, Dordrecht. pp 181-201. equestrianism from the Baroque period to the present day and its Federation Equestre Internationale (2010) FEI List Group Proposes 2011 consequences for the welfare of horses. The role of the horse in Equine Prohibited Substances List for General Assembly Approval. Europe. Equine vet. J., Suppl. 28, 26-30. Available at: http://www.fei.org/veterinary/press-releases/fei-list- Oikawa, M., Takagi, S., Anzai, R., Yoshikawa, H. and Yoshikawa, T. (1995) group-proposes-2011-equine-prohibited-substances-list-general-ass Pathology of equine respiratory diseases occurring in association (accessed 16 October 2010). with transport. J. comp. Pathol. 113, 29-43. Franklin, S.H., Naylor, J.R.J. and Lane, J.G. (2002) The effect of a Parkin, T. (2006) Incidence of distal limb fractures in the UK. In: tongue-tie in horses with dorsal displacement of the soft palate. International Symposium on the Prevention of Thoroughbred Equine vet. J. 34, 430-433. Racehorse Fatalities and Injuries, The University of Melbourne, Goodship, A.E. and Birch, H.L. (2001) Exercise effects on the skeletal Australia. tissues. In: Equine Locomotion, Eds: W. Back and H.M. Clayton, W.B. Perkins, N.R. (2005) Epidemiology of Health and Performance in New Saunders, London. pp 227-250. Zealand. Racehorses, PhD Thesis, Massey University, New Zealand. Hamlin, M.J., Shearman, J.P. and Hopkins, W.G. (2002) Changes in Pool, R.R. (1996) Pathologic manifestations of joint disease in the athletic physiological parameters in overtrained Standardbred racehorses. horse. In: Joint Disease in the Horse, Eds: C.W. McIlwraith and G.W. Equine vet. J. 34, 383-388. Trotter, W.B. Saunders, Philadelphia. pp 87-104. Harman, J.C. (1999) Tack and saddle fit. Vet. Clin. N. Am.: Equine Pract. Racklyeft, D.J. and Love, D.N. (1990) Influence of head posture on the 15, 247-261. respiratory tract of healthy horses. Aust. vet. J. 67, 402-405. Racklyeft, D.J., Raidal, S. and Love, D.N. (2000) Towards an Haussler, K.K. and Erb, H.N. (2006) Mechanical nociceptive thresholds in understanding of equine pleuropneumonia: factors relevant for the axial skeleton of horses. Equine vet. J. 38, 70-75. control. Aust. vet. J. 78, 334-338. Johnston, C., Holm, K., Faber, M., Erichsen, C., Eksell, P. and Drevemo, S. Ridgway, K.J. (1994) Training endurance horses. In: The Athletic Horse, (2002) Effects of conformational aspects on the movement of the Eds: D.R. Hodgson and R.J. Rose, W.B. Saunders, Philadelphia. pp equine back. Equine vet. J., Suppl. 34, 314-318. 409-417. Jones, B. and McGreevy, P.D. (2010) Ethical equitation: applying a Rollin, B.E. (2000) Equine welfare and emerging social ethics. Animal cost-benefit approach. J. Vet. Behav. Clin. Appl. Res. 5, 196-202. Welfare Forum: Equine Welfare. J. Am. vet. med. Ass. 216, 1234-1237. Landmann, M.A.A., de Blaauw, J.A., van Weeren, P.R. and Hofland, L.J. Ross, W.A. and Kaneene, R.B. (1996) An individual-animal-level (2004) Field study of the prevalence of lameness in horses with back prospective study of risk factors associated with the occurrence of pain. Vet. Rec. 155, 165-168. lameness in the Michigan (USA) equine population. Prev. vet. Med. Luthersson, N., Nielsen Hou, K., Harris, P. and Parkin, T.D.H. (2009) Risk 29, 59-75. factors associated with equine gastric ulceration syndrome (EGUS) Tobin, T. (1978) Review of the pharmacology of reserpine in the horse. J. in 201 horses in Denmark. Equine vet. J. 41, 625-630. equine Med. Surg. 2, 433-438. Manfredi, J., Clayton, H.M. and Derksen, F.J. (2005) Effects of different Trotter, G.W. (1996) Intra-articular corticosteroids. In: Joint Disease in the bits and bridles on frequency of induced swallowing in cantering Horse, Eds: C.W. McIlwraith and G.W. Trotter, W.B. Saunders, horses. Equine comp. Exerc. Physiol. 2, 241-244. Philadelphia. pp 237-256.

McGowan, C. and Whitworth, D.J. (2008) Overtraining syndrome in USDA (2001) National economic cost of equine lameness, colic, and horses. Comp. Exerc. Physiol. 5, 57-65. equine protozoal myeloencephalitis in the United States. In: Centres McGreevy, P.D. (2004) Equine Behavior - A Guide for Veterinarians and for Epidemiology and Animal Health: National Animal Health Equine Scientists, W.B. Saunders, London. Monitoring System. USDA:APHIS:VS, CEAH, Fort Collins. McGreevy, P.D. (2007) The advent of equitation science. Vet. J. 174, Van Weeren, P.R. and Crevier-Denoix, N. (2006) Equine conformation: 492-500. clues to performance and soundness? Equine vet. J. 38, 591-596. McGreevy, P.D. (2010) The fine line between pressure and pain: ask the Weeks, C.A., McGreevy, P. and Waran, N.K. (2011) Welfare issues related horse. Vet. J. Epub ahead of print; doi: 10.1016/j.tvj.2010.10.011. to transport and handling of trained and unhandled horses and ponies. Equine vet. Educ. (in press). McGreevy, P.D. and Boakes, R.A. (2007) Carrots and Sticks - The Principles of Animal Training, Cambridge University Press, Cambridge. Welford, D., Mills, D.S., Murphy, K.J. and Marlin, D. (1999) The effect of changes in management scheduling on water intake by the McGreevy, P.D., Cripps, P.J., French, N.P., Green, L.E. and Nicol, C.J. Thoroughbred horse. Equine vet. J., Suppl. 28, 71-72. (1995) Management factors associated with stereotypic and redirected behaviour in the Thoroughbred horse. Equine vet. J. 27, Wilewski, K.A. and Rubin, L. (1999) Bit seats: a dental procedure for 86-91. enhancing performance of show horses. Equine Pract. 21, 16-20.