THE NEED FOR HORSE SPORT TO BE BIT-FREE
THE NEED FOR HORSE SPORT TO BE BIT-FREE
Robert Cook, FRCVS, PhD.
Emeritus Professor, Cummings School of Veterinary Medicine,
Tufts University, USA.
2025
Email: bob.cook@tufts.edu
The beginning of wisdom is to call things by their right names
Chinese Proverb
SUMMARY: The age of a sport born in the Iron Age must be measured in centuries. With the necessary bit-free rule changes, horse sport could celebrate its ‘coming of age’ in the 21st century and have a future. Evidence published since 1999 indicates that, in the racehorse, the bit is the probable cause of pain, suffocation, bleeding from the lung, catastrophic accidents, and sudden death; events that jeopardize racing’s social license to operate. In dressage, one or more bits cause unnecessary pain and poor performance. In recreational riding, the bit causes up to 70 pain-induced conflict behaviors (Cook and Kibler 2018). In racing and other horse sports, negative affective mental states are intensified (Mellor et al 2020). Horses become ‘lame in the lungs’, ‘lame-brained’, ‘legless’ and disabled. Too many die. Collectively, the number of bit-induced diseases, disorders, discomforts, and disasters, is close to 100. Bit-induced pain and fear are incompatible with Learning Theory and the spirit of a sport. Bit-free trials are recommended for all disciplines. The evidence predicts that trial results will validate rule changes for bit-free, ethically sustainable horse sport.
Introduction
The horse’s whiskered muzzle and mouth is a sensory probe that enables horses to feel their way around their world and carefully select what they put in their mouth. The mouth also serves as guardian of the respiratory tract. The horse is a nose-breathing animal. Unless the mouth is closed and the lips are sealed, a galloping horse suffocates. Regrettably, most riders and drivers are still required by competition rules to use a bit, an Iron-Age instrument that breaks the lip seal, handicaps a horse’s ability to breathe, causes pain, and a raft of behavioral side-effects and unintended consequences. Ironically, the mouth-iron method of control is the most common cause of complete loss of control.
Would you like to improve your dressage score from 37% to 64% on day one, bit-free? This was the average improvement that four riders achieved in their school horse’s very first four minutes bit-free at the 2006 Annual Conference of the Central Horsemanship Association (Cook and Mills 2010).
In the bit-ridden racehorse, a toxic combination of mouth pain, fear, suffocation, pulmonary edema, bleeding from the lung, chest pain, a sense of drowning, and physical exhaustion is the probable cause of stumbling, falls, catastrophic accidents, and sudden death (Cook 2022). Jockeys can be seriously injured.
In sum, the mouth-metal method is unreliable, inaccurate and inhumane. The myth that “a bit controls” is precisely that – a myth. A fundamental flaw of the method is that that a horse can chose to render it invalid. Shakespeare (1593) summed it up succinctly – “The iron bit he crusheth ‘tween his teeth, controlling that by which he was controlled.” Bit-ridden horses that are nervous and apprehensive because of pain are more likely than bit-free horses to spook, toss their heads, buck, rear, bolt, or freeze at the foot of a jump and throw their riders.
By comparison, bit-free is safer, pain-free, and more enjoyable for both horse and rider. As a spectator sport, it will be more attractive.
Horses are extremely sensitive animals. They can feel a fly landing anywhere on their skin. They readily respond to a pain-free signal applied to their sensory-probe.
I call as a witness William Cavendish, Duke of Newcastle. In his 1657 classic “The New Method of Dressing Horses” he wrote “…it is not a piece of iron can make a horse knowing, for if it were, the bitt-makers would be the best horsemen: no, it is the art of appropriate lessons … and not trusting to an ignorant piece of iron called a bitt, for I will undertake to make a perfect horse with a cavesson without a bitt, better than any man shall with his bitt without a cavesson; so highly is the cavesson, when rightly used, to be esteemed. I dressed a barb at Antwerp with a cavesson without a bitt, and he went perfectly well; and that is the true art, and not the ignorance and folly of a strange-figured bitt.”
A brief history of a mouth-iron’s impact on the horse
⦁ In prehistoric times it was recognized that the horse (unlike the zebra) was willing to be ridden, thus enabling man to benefit from a horse’s physical ability, strength, and speed.
⦁ The nature of horses is such that they are willing to work for us if, at the very least, two conditions are met. That the partnership is pain-free and does not interfere with their ability to breathe.
⦁ The bit-ridden horse became a weapon of war.
⦁ The bit caused pain, suffocation, and negative affective mental states.
⦁ Early bits were made from wood or antler. These could be bitten through and broken.
⦁ With the development of metallurgy skills in the Iron Age, mouth-metal became customary (Figure 1).
Figure 1. An Iron-Age bit, modelled by a terracotta horse; one of the 520 chariot horses in the ‘Terracotta Army’ Mausoleum of the first Emperor of China 210-209 BCE.
⦁ An internet search for ‘images of iron age bits for horses’ reveals a profusion of assorted designs. This inventiveness has continued to the present day. When so many ‘solutions’ are suggested for the same one problem, this should alert us to the possibility that none are entirely satisfactory.
⦁ Horseracing traces its origins back to 4500 BC (IFHRA, Horse Integrity Handbook 2024).
⦁ In the 19th century, when the rules for racing were drawn up, though the mouth-metal method had never been validated it was ‘grandfathered-in’ without question and made mandatory.
⦁ The method was eventually questioned on the grounds that it caused pain, suffocation and failed to control (Cook 1998 a b,1999 a, b, c, 2000-2024)
⦁ Consolidating evidence of the bit’s harm to horse welfare has come from the comprehensive analyses of Beausoleil and Mellor (2015), Mellor and Beausoleil (2017a, b), Mellor (2017), Mellor (2019 a, b), Mellor, Beausoleil, Littlewood, McLean, McGreevy, Jones, and Wilkins (2020), Mellor and Uldahl (2025), and by Mellor under his pen name Garnham (2024 a, b, c.).
⦁ The Five Domains Model for the Assessment of Animal Welfare (Mellor et al 2020) provided the means for assessing the bit’s impact on the horse. The New Zealand Racing Association was the first to adopt it as their standard, followed quickly by other national racing authorities, and the International Federation of Horseracing Authorities. This landmark advance in equine welfare assessment highlighted the need to reconsider the rules of racing and other horse sports. It is to be hoped that the Federation Equestre Internationale (FEI), the International Horse Sports Confederation (IHSC), and the International Olympic Committee (IOC) will do the same.
⦁ In January 2022, an influential book was published with the title “I Can’t Watch Anymore” and the arresting subtitle ‘The Case for Dropping Equestrian from the Olympic Games. An open letter to the IOC’ (Taylor 2022).
⦁ Today, the bit is widely recognized as a painful foreign body in the sensitive body cavity of a powerful and easily frightened prey animal.
Nevertheless, mouth-metal use continues to be required and is mandatory for racing and for FEI endurance, eventing, and dressage, though not for show jumping. The Netherlands, Denmark, Hungary, and Kenya have led the way by allowing bit-free dressage at all levels short of Grand Prix.
⦁ The Trigeminal nerve provides sensation to the whole of the head (Figure 2). It is a nerve of particular significance in relation to bit usage because of its function as a transmitter of touch and pain signals to the brain from the horse’s sensory probe (muzzle, lips and chin).
Figure 2. The 3 branches of the Trigeminal nerve: sensory to the upper jaw (1) lower jaw (11) and eye (111), with the bit in the ‘tongue-over-bit position
Bit-induced trigeminal neuralgia in the horse, the common and severely painful disease of ‘headshaking’, can be a career-ending disease for a dressage horse.
⦁ The presence in the horse of a trigeminocardiac reflex (Chowdhury and Schaller 2015) has been overlooked as a probable cause of sudden death from cardiac arrest in the racehorse.
⦁ The mandatory infliction of pain in horse sport is ethically unacceptable. Pain is also incompatible with the principles of Learning Theory and the spirit of a sport. It becomes apparent that use of the bit is contrary to the best interests and welfare of both horse and human. As bit-induced injuries and diseases add to the expense of keeping a horse, this is another reason for discontinuing bit usage.
⦁ Thoroughbred racehorses are often encumbered with two bits (i.e., the Dexter Ring Bit; a snaffle and a ring bit). A driving bit is mandatory for Standardbreds in Harness Racing and two bits are present when an overcheck bit is added.
⦁ In recent decades, the bizarre practice of tying a racehorse’s tongue to the lower jaw has been introduced in the mistaken belief that this prevents ‘swallowing of the tongue’, i.e., dorsal displacement of the soft palate (DDSP) and ‘choking-up.’
⦁ More recently, the public have expressed concern about the use of whips. Overlooked is the fact that a bit-armed rein is a whip by another name (Figure 3).
Figure 3. A bitted rein is a whip by another name
⦁ A fundamental goal of dressage is ‘acceptance of the bit.’ Yet ‘acceptance’ of a foreign body in the mouth is physiologically an unrealistic expectation. Horses instinctively reject anything in their mouth other than food or water. Even without rein tension, a mouth-iron is an aversive foreign body in a horse’s mouth.
⦁ For dressage, a double bridle (two bits) was mandatory until quite recently when, in some countries, a single bit became optional in some classes.
⦁ To prevent dressage horses from responding to bit-induced pain by opening their mouth, crank-nosebands became a regrettable and ineffective custom.
⦁ In dressage, the mouth-metal method facilitates ‘riding behind the vertical,’ ‘Rollkur’ and obstruction of the airway. Similarly in Thoroughbred racing, it is a common but questionable strategy for a horse to be ‘rated’ (held in) during the early part of a race.
⦁ The physiology of respiration in the running horse requires a closed mouth, sealed lips, an outstretched head and neck, and a vacuum in the oral cavity (Cook 2020) (Figure 4). Mouth-metal usage disables a horse’s breathing mechanism. (see explanatory diagrams available at Cook 2024a).
Figure 4. A horse running at liberty with a closed mouth and sealed lips. The elliptical shadow posterior to the corner of the mouth is the dimple at the interdental space that marks the presence of the essential negative pressure (vacuum) in the oral cavity, enabling the nose-breathing horse to breathe freely at exercise. The straight edge of the dimple marks the roof of the mouth (hard palate). The vacuum clamps the soft palate to the root of the tongue, preventing it from elevating during each inspiration and causing suffocation. A good time to observe the dimple is when a horse is drinking, an activity dependent on oral cavity negative pressure. A bit-ridden endurance horse has difficulty drinking.
⦁ Mandatory mouth-metal usage and the infliction of pain is incompatible with horse welfare and the spirit of a sport.
⦁ Deprived of a fundamental need, a galloping horse suffocates. Diagrams illustrate numerous points in the respiratory tract at which bit-induced airway obstruction occurs (Cook 2024a). A law of physics governing the flow of gases in tubes (Poiseuille’s law) explains why bit-ridden racehorses bleed from the lungs, become exhausted, stumble, fall, break bones, dislocate joints and die sudden deaths.
⦁ Visible signs of airway obstruction during exercise include an open mouth, lack of head/neck extension, hyperflexion (Rollkur), and seeing blood at the nostrils during or immediately after exercise. Endoscopic signs (at rest or during exercise with overground endoscopy) include dislocation of the throat airway (dorsal displacement of the soft palate), epiglottal entrapment, laryngeal paralysis or partial paralysis. In human medicine, the effects of lung edema caused by airway obstruction include severe chest pain, a sense of drowning and intense fear. It is reasonable to infer that bit-induced suffocation and asphyxia in the horse could cause similar effects. Sheer physical exhaustion could also be followed by stumbling, falls, catastrophic accidents; and sudden death from bit-induced asphyxia or from activation of a trigemino-cardiac reflex, i.e., a ‘heart attack’. (Chowdhury and Schaller 2015, Cook 2022).
⦁ Exercise-induced hypoxemia (shortage of oxygen) in the Thoroughbred is a recognized condition. I am not aware of any studies that have compared the severity of this condition in Thoroughbreds exercised with and without a bit, or in Thoroughbreds with and without the common scourge of ‘roaring’, i.e., left-sided recurrent laryngeal neuropathy (paralysis or partial paralysis of the voice box). Looking ahead, to the time when bit-free racing has become the norm and mouth-metal is disallowed, it may finally be noted that ‘roaring’ and other wind problems no longer occur (i.e., that bit-induced hypoxemia was the cause of laryngeal neuropathy).
⦁ The Trigeminal nerve is the major sensory nerve to the head (Figure 1). As its name suggests, the nerve has three major branches: to the eye, upper jaw and lower jaw. The end fibers of all three branches are intimately entwined with another nerve (the Vagus) that regulates the heart. As mouth-metal stimulates all three branches simultaneously, on both sides of the head, this explains why a bit-ridden racehorse might die of a heart attack from activation of a trigeminocardiac reflex.
⦁ The cornea of the horse’s eye is another region of high sensitivity (Figure 5). On a wet turf or dirt track, the shod hooves of the horse in front scoop up dirt and debris at every stride and kick it in the face of the following horse and jockey. An oculo-cardiac reflex is a recognized cause of cardiac arrest during eye surgery in man.
Figure 5. SOVEREIGNTY ‘S jockey, Junior Alvarado, after winning the Kentucky Derby on a muddy Saturday in May 2025. The horse had no goggles.
⦁ Because a bit repeatedly and simultaneously stimulates all three branches of the Trigeminal nerve, the bit is a common cause of headshaking (Cook and Kibler 2018). This bit-induced conflict behavior was all too obvious in the carriage horses at the royal wedding of Prince Harry and Meghan Markle (Fox 2018a b). As opined by veterinarian Michael Fox, “Obvious oral discomfort at a Royal Wedding. Time for the royal horse brigade to get with the times and put animal welfare and respect before blind tradition.”
⦁ The mouth-metal method is a form of invasive surgery. The etymology of the word ‘surgery’ means “a working with the hands.” It is a daily, invasive procedure without anesthesia, involving manual work from a distance while both horse and rider are on the move. As the rein is flexible, the method provides for increase and release of mouth-iron pressure on the sensitive mouth.
However, release is strongly dependent on the rider having an independent seat, a rare skill. When riders instinctively and understandably throw their body weight on both reins to retain their balance, no release occurs, quite the opposite. Similarly, while a dressage horse is kept ‘on the bit’ with rein tension and constant contact there will be no release. A jockey, standing in the stirrups at a full gallop, will often be balancing by applying mouth-metal pressure on both sides of a racehorse’s mouth
⦁ 34. An important contribution to the science of horse sport has been made by Crispin Johannessen and his use of high-definition evidentiary photography (Wilkins et al 2025). His images significantly enhance our recognition of a bit’s harmful effects. In a 50-minute video, Johannessen and his colleagues comment on a library of photographic evidence that he compiled at two international dressage competitions this year. Once seen, this video cannot and should not be forgotten. Gaping mouths, cyanotic (painful) tongues, and ‘wild’ eyes with sclera exposed tell the unhappy story (Figures 6-16).
⦁ Figure 6. A dressage horse harnessed with a double bridle. The snaffle and curb reins are taut. The nasal plane is close to the vertical and the jowl angle is reduced, as is airflow to the lungs. The lips are unsealed, so the airway will be further obstructed by soft palate elevation at each intake of air. Bit pressure will cause pain, particularly that from the curb applying point pressure on the knife edge of periosteum at the bars of the mouth. Bit pressure has slowed the circulation of oxygenated blood to the tongue, hence its cyanotic color. The lack of oxygen will cause the horse to experience an acute ishaemic pain in the tongue. By preventing normal extension of the head and neck at exercise, airflow is restricted. This may also interfere with venous drainage of blood from the head, so accounting for the swelling (convexity) at the poll, and loss of the normal concavity above the eye.
Figure 7 . Another dressage horse in a double bridle at an international horse show exhibiting clinical signs similar to the above figure. The eyelids are swollen and there is swelling of the hollow above the eye. The tongue is cyanotic and swollen.
Figure 8. The Dexter Ring Bit, a snaffle and ring bit. A type of ‘double bridle’ frequently used on racehorses. A ring bit’s intended purpose is to add to the severity of the snaffle, keep the snaffle ‘centered’ in the mouth, and prevent horses from getting their tongue over the bit. See figure below.
Figure 9. A Dexter Snaffle and Ring bit on a racehorse. The lips are unsealed. The apex of the tongue is not as pink as it should be but otherwise normal, exhibiting its spatula-like conformation.
Figure 10. The Chiffney bit: a predecessor of the Ring Bit, sold as an anti-rearing bit and used for leading a horse from the ground. Whether it served its intended purpose is questionable. Any bit is itself a cause of rearing.
Figure 11. RICH STRIKE pre-race, winner of the Kentucky Derby (2022), harnessed with a Dexter Ring Bit. The spatula-like conformation of a normal tongue’s apex is apparent.
Figure 12. A good example cyanosis of the tongue can be recognized by comparison with the healthy color of the gums. The normal pink gum tissue and the cyanotic, swollen tongue. The vice-like action of the curb bit and chin chain
on the jawbone is apparent.
Figure 13. Showing the normal hollow above the eye of a healthy horse.
Figure 14. An unhappy dressage horse exhibiting pain from a double bridle; the open mouth, a ‘wild’ and bloodshot eye, and swelling of what should be a concavity above the eye and below the browband.
Figure 15. A close-up of the above figure, showing the blood-shot sclera of the eye
and the swelling above the eye.
Figure 16. A close-up of another horse with a ‘wild’ eye and a swelling above the eye, marked by a red spot at its front end.
Figure 16. Hyperflexion in a dressage horse with double bridle, competing internationally.
35. Mandatory autopsy examinations of horses that have died on the racetrack will not disclose confirmatory evidence of the bit’s harm until the protocols are updated, and their reporting standardized (Cook 2022). Currently, autopsy reports are not required to list what bits were used, whether there was bit-induced damage to the bars of the mouth or the molar teeth, tracheal deformity, or laryngeal muscle atrophy from recurrent laryngeal neuropathy.
35. For the last 12 years or more, the Royal Dutch Equestrian Federation have allowed bit-free virtual dressage.
35. In 2024, thanks to the recommendation by Dr. Andrew McLean, the Australian Pony Club allowed its members to compete bit-free on application. Other Pony Clubs around the world are following suit.
36. The Danish Equestrian Federation is in the process of reviewing its rules and regulations
37. Dr. Niels Fuglsang has called on the Parliament of the European Union to protect sports horses by law; to ban double bridles and any other type of curb bit.
38. In 2024, an article was published in Poland with the subtitle, “When does sports autonomy become an excuse for animal abuse?” (Lubelska-Sazanow 2024). The article “aims to answer the questions of whether equestrian sports constitute a general exemption to their being considered animal abuse and on what grounds this exemption might be changed in the future.”
39. Important aspects of a horse’s ridden behavior await study. For example, what is the effect of mouth-metal on a horse’s length of stride and speed? With the availability of Global Positioning System (GPS) technology, these are questions that could be answered. My expectation is that bit-free riding will be shown to increase both parameters.
40. In the study “Behavioural assessment of pain in 66 horses, with and without a bit.” (Cook and Kibler 2018) it was documented, for the first time, the significant degree by which 69 bit-induced pain behaviours were reduced by riding bit-free for a mean period of 30 days (see Table 1, Cook and Kibler 2018). The mean reduction was 87% (range 43–100%). Many of the bit-induced pain indices jeopardized the safety of both horse and rider.
41. Long-term experience with the bit-free method has shown that improvement in behavior after a month continues in succeeding months. Repeating assessments at 3, 6, and 12 months would document such improvement. The owner of one horse which, when bit-ridden, was dangerous to ride, reported that after the first month of substantial improvement, the horse continued to show further improvement for the next four years, at which stage the horse was completely rehabilitated.
42. Communication occurs from rider-to-horse and from horse-to-rider. Just as a rider’s use of mouth-metal affects a horse’s behavior, so might it be expected that the characteristically nervous and spooky behavior of the bit-ridden horse would affect a rider’s feelings about riding. In the second part of the questionnaire study (Cook and Kibler 2018), the effect of bit-induced pain in the horse on the rider’s feelings was studied for the first time (Cook and Kibler 2022). An additional ten questions were answered by 45 of the 66 riders who reported how their feelings about riding changed after they had ridden bit-free for about a month. When using a bit, 45 riders reported having 200 negative feelings about riding. When bit-free, they reported 18, a reduction of 91%. The rider’s feelings were negatively influenced by their horse’s aversion to mouth-metal.
43. As a ‘footnote’ (pun intended), another factor relevant to the question of heart attacks in racehorses relates to the health of the horse’s hoof. Concurring with the horse’s further domestication in the Middle Ages, two additional practices became customary: shoeing and stabling. These medieval handicaps negatively impact hoof health and horse welfare (Strasser and Kells 1998, Cook 2002b). The normal function of the hoof is to expand and contract at each step. This ensures a healthy blood supply to the hoof and retains its inherent flexibility. While galloping, each hoof acts as a supplementary vascular pump, assisting the action of the heart in maintaining blood flow throughout the body. The nailing of a metal clamp on each hoof interferes with the effectiveness of this function and places an additional burden on a heart that is already under stress because pulmonary edema will massively increase resistance to blood flow through the lungs.
CONCLUSION AND RECOMMENDATION.
When bit usage was tested, it was found to be the cause of pain, fear and many conflict behaviors. Mandated-bit rules were shown to be inhumane, dangerous, and unnecessary.
Bit-free trials are recommended for all disciplines of equestrian sport. If the results are as supportive of bit-free usage as the evidence for bit-free indicates (Cook 2024b), rules mandating bit usage can be taken off the books and horse sport made bit-free.
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Disclaimer
I marketed a bit-free bridle from 2000-2016*. For the last nine years, I have had no conflict of interest to declare.
*Manufacturer’s Address: PHS Saddlery, www.phssaddlery.com
5220, Barrett Rd., Colorado Springs, 80926.
REFERENCES and further reading
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Bonner, J. (1998): “Changing Tack; horses may prefer bridles with a bit missing.” New Scientist, 4 July.
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https://www.britishhorseracing.com/press_releases/a
Chowdhury, T and Schaller, B.J. (2015): “Trigeminocardiac Reflex” Academic Press, Elsevier Inc.,
Cook, W.R. (1989): “Specifications for Speed in the Racehorse: the airflow factors” The Russell Meerdink Company, Menasha, Wi, USA.
Cook, W. R. (1993): “Exercise-induced Pulmonary Hemorrhage in the Horse is Caused by Upper Airway Obstruction.” Irish Veterinary Journal, 46: 160-161
Cook, W.R. (1998a): “Use of the bit.” Veterinary Record, 142,16
Cook, W.R. (1998b): “Use of the bit.” Veterinary Record, 142, 676
Cook, W.R. (1999a): “Pathophysiology of Bit Control in the Horse.”
Journal of Equine Veterinary Science 19(3):196-204
DOI: 10.1016/S0737-0806(99)80067-7
Cook, W.R. (1999b): “The Ear, the Nose, and the Lie in the Throat.” Guardians of the Horse, Past, Present and Future. British Equine Veterinary Association and Romney Publications, p175-182
Cook, W.R. (1999c): “Asphyxia as the cause of bleeding and the bit as the cause of soft palate displacement.” Thoroughbred Times, Guest Commentary. November 27, 18-19.
Cook, W.R. (2000): “A solution to respiratory and other problems caused by the bit.” Pferdeheilkunde, 16, 333-351
Cook, W.R. (2001a): “The Penalties of the Bit and the Benefits of Bitlessness.” Pferdegesunde
Cook, W.R. (2001b): “On Talking Horses: Barefoot and Bit-free.” Natural Horse Magazine, 3, 19
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Cook, W.R. (2001d) “Alternative Drooling Research”. Dressage Today. November. p15
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Cook, W.R. (2002b): “On ‘Mouth Irons’, ‘Hoof Cramps’, and the Dawn of the Metal-Free Horse.” Natural Horse, August 2002, vol 4, issue 4, pp 37-40
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Cook, W.R. (2003a)): “Bit-induced Pain; a cause of fear, flight, fight and facial neuralgia in the horse.” Pferdeheilkunde, 19, 1-8
Cook, W.R. (2003b): “Fear of the Bit: A Welfare Problem for Horse and Rider”. Parts I-III. Available with others at www.bitlessbridle.com/
Part I “Why Horses Hate the Bit.”
Part II “Bit-induced Diseases and other Indictments.”
Part III “Behavioural Profiling Questionnaire.”
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https://www.horsetalk.co.nz/2018/12/09/unintended-consequences-preparing-big-horse/
Cook, W.R. (2019): “Horsemanship’s ‘elephant-in-the-room’ – The bit as a cause of unsolved problems affecting both horse and rider.” Weltexpress: https://en.weltexpress.info/2019/02/15/horsemanships-elephant-in-the-room-the-bit-as-a-cause-of-unsolved-problems-affecting-both-horse-and-rider/
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Cook, W.R. (2022): “Does use of a bit endanger the health and safety of horse and rider?”
https://worldbitlessassociation.org/resources/does-use-of-a-bit-endanger-the-health-and-safety-of-horse-and-rider-professor-robert-cook-july-2022/
Cook, W.R. (2022): “Sudden death in the racehorse.”
https://worldbitlessassociation.org/resources/sudden-death-in-the-racehorse/
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Why not bit-free? Time to draw the equestrian iron age to a close
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Data and Visual evidence for the Bit-free debate – World Bitless Association
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The Evidence for Allowing a Bit-Free Option in Equestrian Sport (horsesandpeople.com.au)
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Cook, W.R, Williams R.M, Kirker-Head, C.A. and Verbridge, D.J (1988): “Upper Airway obstruction (partial asphyxia) as the possible cause of exercise-induced pulmonary hemorrhage in the horse: a hypothesis.” Journal of Equine Veterinary Science, 8: 11-26
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Cook W.R. and Kibler, M. (2018): “Behavioural assessment of pain in 66 horses, with and without a bit.” Equine Veterinary Education. https://doi.org/10.1111/eve.12916 [Table 1 lists the behaviors in order of frequency and documents the percentage improvement in each behavior following removal of the bit]
Cook, W.R. and Kibler, M (2022): “The effect of bit-induced pain in the horse on the feelings of the rider.” https://worldbitlessassociation.org/resources/the-effect-of-bit-induced-pain-in-the-horse-on-the-feelings-of-riders-about-riding-2022/
Douglas, J, Owers, R, and Campbell, M. L.H. (2022):
“Social Licence to Operate: What Can Equestrian Sports Learn from Other Industries?” Animals 2022, 12(15), 1987; https://doi.org/10.3390/ani12151987 2
Fox, M.W. (2018a). “Horses at the Royal Wedding.” Veterinary Record, vol182, Issue 21, p608-608
Fox, M.W. (2018b) “The Royal Wedding and Horse Welfare.” Animal Doctor, June 10th, 2018
Garnham, J. (Mellor D.J.) (2024a). “Thoroughbred Horse Welfare Challenges: From Rape to Relegation.” Horses and People, July 2024: https://horsesandpeople.com.au/thoroughbred-welfare-challenges-from-rape-to-relegation/
Garnham, J. (Mellor D.J.) (2024b). “Improving Sports’ Horse Welfare: A Way Forward.” Horses and People, September 2024: https://horsesandpeople.com.au/improving-sports-horse-welfare-a-way-forward/
Garnham, J. (Mellor D.J). (2024c). “Seven Pillars of Deception to Delay Action on Horse Welfare,” Horses and People, October 2024: https://horsesandpeople.com.au/seven-pillars-of-deception-delaying-action-on-horse-welfare/:
Harvey, A. (2023): “A Bit of a Problem in Equine Welfare: What is the Role of Veterinarians?” Center for Veterinary Education, Control and Therapy Series, Number 6001. Issue 313, pp23-26. 8.
IFHRA (2024): “International Federation of Horseracing Authorities’ Horse Integrity Handbook.”
Jockey Club (2019): “White Paper RACING. Vision 2025. To Prosper, Horse Racing Needs Comprehensive Reform.” http://www.jockeyclub.com/pdfs/vision_2025_updated.pdf
Lubelska-Sazanow, M (2024): “Ethics in sports industry: When does sports autonomy become an excuse for animal abuse?” International Journal of Law in Context, 1–17 doi:10.1017/S1744552324000193
Mellor, D.J. (2019a): “Equine welfare during exercise 1. Do we have a bit of a problem?” Scribd Everand.
https://www.slideshare.net/SAHorse/equine-welfare-during-exercise-do-we-have-a-bit-of-a-problem
Mellor, D.J. (2019b): “Equine welfare during exercise 2. Do we have a bit of a problem?” https://www.youtube.com/watch?v=rY4yEC71hco
Mellor, D.J. (2020): “Mouth Pain in Horses: Physiological Foundations, Behavioural Indices, Welfare Implications, and a Suggested Solution.”: Animals https://www.mdpi.com/2076-2615/10/4/572
Mellor, D.J. and Beausoleil, N.J. (2017a). “Equine welfare during exercise: An evaluation of breathing, breathlessness and bridles.” Animals 7(6), 41;
doi:10.3390/ani7060041 or http://www.mdpi.com/2076-2615/7/6/41
Mellor, D.J. and Beausoleil, N (2017b): “More pressure on the bit. Researchers talk of a significant welfare issue.” Horse Talk
https://www.horsetalk.co.nz/2017/09/01/pressure-bit-animal-welfare-issue/
Mellor, D.J.; Beausoleil, N.J.; Littlewood, K.E.; McLean, A.N.; McGreevy, P.D.; Jones, B.; Wilkins, C. The 2020 Five Domains Model: Including Human–Animal Interactions in Assessments of Animal Welfare. Animals 2020, 10, 1870. [Google Scholar] [CrossRef]
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Animals 2025, 15(6), 821; https://doi.org/10.3390/ani15060821
Shakespeare, W (1593): “Venus and Adonis.”
Strasser, H. and Kells, S (1998): “A lifetime of Soundness: The Keys to Optimal Horse Health, Lameness Rehabilitation, and the High-Performance Barefoot Horse.” Third edition (revised). Sabine Kells, Qualicum Beach, BC V9K 1S7, Canada,1998
Taylor, J (2022): “I Can’t Watch Anymore: The case for dropping equestrian from the Olympic Games. An open letter to the IOC.” Epona Media Copenhagen www.epona.tv
Wilkins, C.; Henshall, C. McGreevy, P, Mellor, D.J. Tuomola, K; Johannessen, C.P; Lykins, A. (2025): “Welfare in Dressage: Visual and Scientific Evidence. A 50-minute briefing entitled ‘Equipment-induced Pressures Affecting Sport Horses. Evidence and welfare impacts.’ delivered to the FEI Veterinary Committee on 9 April 2025.”
Available online https://www.youtube.com/watch?v=W6OgVEC4i28 )