Firstly, this article is about a basic need of the ridden and driven sport horse, the need to breathe. Secondly, it is about the role of veterinarians in drawing attention to this need to breathe. Thirdly, it is about the responsibility of horse sport administrators to provide for the need breathe, a step that will prevent their sport being banned.

The Obligatory Nose-breather

The horse is a nose-breathing animal, unable to breathe freely when running if the lips are not sealed. At liberty, a horse runs with a closed mouth, sealed lips, and a straightening of the airway from nostril to lung. Unless a horse, when preparing to run, can seal its lips, swallow, establish and maintain a negative pressure in their oral cavity, they are unable to breathe freely when running, because of being throttled by an ‘untethered’ soft palate (Cook 2019a).

The use of one or more bits, with or without a tongue tie, breaks the lip-seal and causes a cascade of problems such as mouth pain, conflict behavior, palatal instability, suffocation, chest pain, fear, and a sense of drowning. In racing and other high-performance sports, an exhausted horse with waterlogged and bleeding lungs may fall, incur a catastrophic injury, or die a sudden death (Cook 1999, 2022, 2023a b). Riders can be seriously or fatally injured.

The above consequences of bit usage are based on evidence I have published in the last 25 years (see references below) and publications by Beausoleil and Mellor (2015), Mellor and Beausoleil (2017), Tuomola et al (2019), Mellor (2019a, b), Mellor (2020a b), Mellor et al (2020), Luke et al (2021), and others (see references below).

Why Breathing?

After graduating in 1952, my field of research since 1958 has been the equine mouth, ear, nose, and throat. In December 2023, an article with the title “A Bit of a Problem in Equine Welfare: What is the Role of Veterinarians?” (Harvey 2023) was published in Australia by Sydney University’s Centre for Veterinary Education. The author listed the topics of some of my publications up to 1998, then focused on my work when – regrettably late in my career – I asked myself the question, “What does a bit do to a horse?”

Regarding my work on the bit, Harvey observed that “This substantial body of research, however, has been largely overlooked by mainstream equestrian industries, and indeed by the veterinary profession. Why is this? Why is something so important that impacts so many horses on a daily basis totally overlooked in veterinary education and by so many equine veterinarians?”

A short answer is that scrutiny of an Iron Age method of rider/horse communication did not start until the closing years of the last millennium (Cook 1999). The delay of 25 years since then is understandable, considering the time it takes to accumulate a body of evidence, for the evidence to be published, assimilated, and for resistance-to-change to be overcome after 3 millennia of metal bit usage. Whereas a change in public opinion can occur quickly, a change in the opinion of stakeholders and the structure of a sport is a slower process. However, as a serious structural flaw in horse sport has become evident, its survival now depends on discontinuing an Iron Age methodology (Cook 2023a b).

Harvey’s observation is corroborated by two recent surveys. In a 2022 review of equine welfare by the Equine Ethics and Wellbeing Commission, the word ‘bit’ was entirely absent (International Equestrian Federation 2022). Again, in a 2023 Delphi review of ‘Sporthorse Health and Welfare in the Olympic Disciplines’, the bit was mentioned only twice in a 16,000-word document, both times in relation to the 2018 Dutch petition to ban coercive training methods (Williams et al 2023).

The continued use of an Iron Age method explains why catastrophic accidents and sudden deaths occur and why the social license of horse sport is being questioned. Advocacy by veterinarians for the health and safety of horse and rider is urgently needed, together with action (the banning of bits) by horse sport’s administrators.

Adopted initially to weaponize the horse for war, the metal bit’s military background entrenched the myth that the bit (i.e., pain) controls a horse. The bit became ‘standard practice’ despite the claim by the father of dressage William Cavendish (1592–1676) that he could ‘dress’ a horse with a scarf, implying that pain is not needed (Cook and Strasser 2003). Horseracing administrations have augmented the Iron Age mistake by allowing two bits (the ring bit) and a further barbaric device, the tongue-tie (Franklin et al 2002, Franklin and McGreevy 2010, Mellor 2020a). Two bits (the double bridle) are also mandated by most dressage administrations. A book published after the 2020 Tokyo Olympics makes the case for dropping equestrian sport from future Olympic Games and draws attention to many other welfare problems in horse sport (Taylor 2022).

Rules, Science, and Learning Theory

Rules of organizations, like laws of countries, have always needed to be updated to keep them consistent with advances in science, changes in ethical standards and cultural attitudes. It is not surprising that horse sport rules drawn up in the 17th century are out of date. This has come about because of the time it has taken for science to be applied to a method of rider/horse communication developed in antiquity. We need to correct problems that have arisen because of the lack of scrutiny.

Racing’s rules were first drawn up 400 years ago. Though bit use is mandatory for many equestrian sports, it is not mandatory for racing. Nevertheless, as equipment is at the discretion of the stewards, and is ‘required’ as standard practice, the effect is the same. In the 18th century, when Britain’s Jockey Club was founded, bit usage became the norm, even though it was not mandated. Since then, as other competitive horse sport disciplines were formalized in the 19th and 20th centuries, most administrations followed ‘standard practice’ and mandated bit usage. Pony Clubs worldwide are independent of the FEI (Fédération Équestre Internationale), but they too aligned their rules with the FEI, as did 4H organizations . As a result, children must use equipment that jeopardizes their own and their horse’s safety.

However, on July 4th, 2023, Pony Club of Australia set an example by announcing that, in response to demand, riders may now apply for an exemption to ride bit-free on the grounds of horse welfare. They have updated their rules so that a rider of any age can apply for exemption from bit usage, not just for rally days, but for any competition across any discipline.

Scientific evidence relative to rein-aid communication was not brought to bear on this topic until the start of the present century, when learning theory was first applied to horsemanship (McGreevy and McLean 2007, Hawson et al 2010, McLean and McGreevy 2010). However, the principles of learning theory cannot logically be applied to the bit-ridden horse. The first of its ten principles states that the theory recognizes the horse’s behavior and social organization, recommending that fear responses are to be avoided. But bits are a major cause of fear in horses (Cook and Kibler 2018, Mellor 202a). Pain and fear are inimical to learning.

The International Society for Equitation Science endorses the minimal use of aversive stimuli and defends negative reinforcement by recommending bit ‘pressure-and-release’ (ISES 2018). But another word for bit pressure on bone is pain (Mellor 202a). Gum on the bars of the mouth is the highly sensitive ‘skin’ of the jawbone. Pain, in turn, causes fear (Mellor et al 2020). As explained, the bit is horsemanship’s ‘elephant-in-the-room’ (Cook 2019a, 2023a, 2023b).

Mandatory-bit rules deny the horse a basic need and cause pain. In some countries, bit usage may infringe animal cruelty laws. The present crisis in racing represents an opportunity which, if addressed, could lead to a paradigm change in all equestrian sport. Much would be gained if racing were to be seen to be making an informed effort to discover the cause of catastrophic breakdowns and sudden death. Before the process can get started, horse sport’s administrators need to recognize the bit’s harm and to act accordingly. A step in the right direction would be to conduct bit-free training trials.

The theory that ‘bleeding’ in the racehorse could be caused by upper airway obstruction was first advanced many years ago (Cook et al 1988, Cook 2014) and has been reinforced by further analyses (Mellor and Beausoleil 2017).

To date, no cogent refutation of the theory has been provided and the evidence in support (much of it cited above) has been steadily mounting. I maintain that:

  • Exercise-induced pulmonary hemorrhage (EIPH) is no longer an appropriate name for this ubiquitous scourge of the racehorse.
  • Airway obstruction in human medicine is a rare but life-threatening disease that is appropriately named negative pressure pulmonary edema (NPPE). The name indicates the disease’s anatomical location (the lungs), its pathology (edema, i.e., ‘waterlogging’) and its cause (abnormally strong suction pressures at each forced breath that bruise the delicate air sacs of the lungs).
  • To emphasize its cause and treatment, EIPH should be renamed NPPE.
  • Whereas in man NPPE is rare and accidental – in the racehorse it is common and caused by bits and tongue ties. Racehorses breathe in pain.
  • If racing’s stakeholders have valid evidence for refuting the above, it should be published as a matter of urgency.
  • If they have no such evidence, they should explain why they have not yet considered the potential impacts of bit use in their evaluation of accidents and sudden deaths.
  • A study indicated that 71% of 283 Thoroughbred racehorses exhibited conflict behaviors at the starting gate (Pearson 2018). Two of the four behaviors described (i.e., stopping and rearing) have been shown to be elicited by the bit (Cook and Kibler 2018).

Conclusions and Historical Postscript

A bit strangles a horse, causes pain and is an impediment to communication. A bit-tipped rein is a whip by another name – a mouth whip. I recommend that use of the bit should be banned and that this will…

  • Reduce the prevalence of bit-induced problems that currently occur in racing (e.g., ‘bleeding,’ catastrophic injuries, and sudden death).
  • Increase the overall safety of horse sport by reducing risk for both horse and rider/driver.
  • Improve the general public’s perception of horse sport.
  • Justify the continuance of horse sport’s social license to operate.
  • Enable a racehorse to be retired from racing in better health, eligible for a life after racing.

After the regrettable incidents that occurred in the 2021 Tokyo Olympics, the French National Assembly (the lower house of the French Parliament) recommended 46 rule changes for the 2024 Paris Olympics (Wilkins 2022). How many of these recommendations will be adopted has not yet been announced.

Over 130 years ago, a perceptive graduate of the Royal Veterinary College, London wrote “Save when needless severity urges timidity to madness, the horse is naturally obedient. This is the instinct of the race. … All its learning is attention to the sounds of the human voice. It is guided by touches. … Let every owner of a horse treat his slave with gentleness. … Above all things, let no individual employ the reins as an instrument of torture” (Mayhew 1890).

Various modes of forming that which all men speak of with admiration, as ‘a good mouth.’ (Mayhew 1890)

Various modes of forming that which all men speak of with admiration, as ‘a good mouth.’ (Mayhew 1890)

Mayhew’s phrase “guided by touches” draws attention to a feature of equine physiology of special relevance, the horse’s highly developed sense of touch. As he noted, a horse can detect and respond to the touch of a fly anywhere on its fine-haired skin. Skin is a sense organ and lips are one of its most sensitive parts. Horses are understandably ‘touchy’ about the mouth.

The touch of a bit is invasive, prolonged, painful, and repeated daily throughout a horse’s working life. It is the cause of side-effects that trigger a repertoire of not less than 69 stereotypic, unwanted, conflict behaviors (Cook and Kibler 2018). It constricts the airway, causes trigeminal neuralgia (‘headshaking’), erodes teeth, and damages the jawbone (Cook 2010c). It also deforms the windpipe, bruises the lungs, causes imbalance, stumbling, falls, catastrophic accidents and sudden death. Apart from being inhumane and potentially fatal, as a signaling method use of the bit is unreliable, inaccurate, inefficient, and often misunderstood by the horse, leading to unwanted behaviors that jeopardize the health and safety of the rider (bucking, rearing, bolting etc.,).

Since 2000, an abundance of pain-free bridles has become available that comply with LIMA principles (Least Intrusive and Minimally Aversive). The well-distributed touch of strap on skin, compared with the pin-point pressure of metal on bone, can be painless and provides a clear signal without negative side effects.

The Five Domains Model (Mellor et al 2020) provides a systematic method for assessing the negative effect of the bit on horse welfare. In his review of mouth pain in horses (Mellor 2020a) the author concluded, “So, how might we proceed? We cannot simply ignore the bit problem, which has now been identified so clearly. Inaction when a problem is not apparent is understandable. Inaction once a significant problem has been recognized is unacceptable. Recognition of such a problem brings with it an ethical responsibility to act.”

Learn to apply the Five Domains Model in practice!


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