Seeking to remove a source of serious discomfort for horses

01 February 2010, at 12:00am

JOHN BONNER talks to Professor Bob Cook about his passion for a bitless bridle

EQUINE veterinarian Bob Cook has spent a decade battling against what he regards as a brutal throwback to a Bronze age culture. The struggle has been lonely and frustrating but he now believes that the equestrian world may at last be ready to accept his claim that putting a metal bit into an animal’s mouth to control its movements endangers the health and safety of both horse and rider. 

Professor Cook became interested in the behavioural and physiological effects of the traditional bitted bridle in the late 1990s after retiring as head of equine surgery at Tuft’s University veterinary school in Massachusetts. He was asked to investigate an unconventional bitless bridle which, through a crossover arrangement beneath the horse’s chin, applies pressure on the side of the head rather than the delicate structures of the mouth.

He became convinced that the conventional bit is a continuous source of serious discomfort for vast numbers of horses. He has catalogued around 100 behaviours such as bolting, bucking and rearing which he believes are caused by the presence of this alien object in the horse’s mouth.

“You can call these vices or negative behaviours but I would argue that they are neither, they are just a normal reaction on the part of animal to its feelings of fear and pain.”

More importantly, his research indicates that a bitted bridle can have serious ill effects on the horse’s ability to breathe properly, particularly during the stresses of competition. So this could be a significant causative factor in up to 40 separate disease states including exercise-induced pulmonary haemorrhage, epiglottal entrapment and dorsal displacement of the soft palate. 

Moreover, he insists that the fatigue resulting from asphyxia during competition may predispose a horse to the sort of catastrophic musculoskeletal injuries that can prove fatal for both the horse and its rider.

A 1952 RVC graduate, Bob conducted research on conditions affecting the horse’s head and respiratory system at three UK veterinary schools and at the Animal Health Trust before crossing the Atlantic. He worked for two years at the University of Illinois before being recruited by the newly formed Tuft’s school in 1979.

He was introduced to the concept of the bitless crossover bridle by a Californian horseman, Allan Buck, who was selling a version that he called the “Spirit bridle”. But the basic idea has certainly been around since the 19th century. There are also a number of other designs which dispense with the traditional bit including those devices known as hackamores, bosals and sidepulls.

Yet these share the same flaws as the crude technology originally developed by the Scythian horsemen of central Asia in about 5000 BC. Each is used to cause pressure on the mouth or the bridge of the nose – the crossover design is the only one that controls the horse without causing it pain, he says.

He carried out studies on the impact of this basic bridle on horses which showed signs of distress when ridden using traditional tackle. Very quickly he became convinced that many of the clinical conditions that he has seen throughout his career were a result of the problems caused by the bit.

He made a few modifications to the design which were patented in the US and formed a company which sells this kit through his website, . Similar products are available from other companies which have sprung up in various countries around the world, including the UK.

The idea of using bitless tackle has been taken up with great enthusiasm by leisure riders in the US and abroad and his website contains a large number of unsolicited testimonials on the beneficial effects that this simple device has had on the experiences of the owners.

This acceptance of the new technology has, however, largely resulted from word of mouth recommendations – there has been minimal support from his veterinary colleagues in his campaign to change the technology used to control their client’s animals.

“The profession in the US and UK has taken very little notice of the work I have done over the past 10 years. I don’t think they have woken up to the fact that the bit can explain so many of the idiopathic diseases that equine practitioners have worried about for generations.

“I can’t really explain why. I suspect that most veterinary surgeons have regarded the bit as a mystery which isn’t really their province and have left these issues to the horse owners.”

The attitude of the regulatory authorities for equestrian sports has been even less encouraging. The United States Equestrian Federation insists that bitted bridles are used by all riders competing in all dressage competitions organised under its jurisdiction although, curiously, these are not mandatory requirements for the cross country or show jumping disciplines.


“I haven’t been able to persuade the US authorities to even look at my data. You can put it down to the conservatism and tradition that is part of this world but there is also a big dose of sheer wooden-headedness,” he says.

Two recent developments have given Professor Cook hope that professional colleagues and the competitive horse world may be ready to accept his arguments for the benefits of bitless bridles. The November 2009 edition of the Equine Veterinary Journal carried a paper co-written with Daniel Mills, professor of veterinary behavioural medicine at the University of Lincoln, directly comparing the performance of four horses ridden with a conventional snaffle bridle and his own design.

The study took place at the US Certified Horsemanship Association conference in October 2008 in which the horses carried out two four-minute exercises with the same rider, which were viewed by an independent judge. Two of the horses had never been ridden with a bitless bridle before and in the overall group there was an average 75% improvement in the performance after switching to the new bridle.

Professor Cook hopes that now the study has appeared in a reputable journal, other equine scientists will be persuaded to conduct research on the behavioural and physiological effects of the bit. Even more importantly, the equine sports authorities have begun to show a willingness to consider a change in the rules.

In 2008, the Dutch equestrian authority became the first association to allow the use of the crossunder bridle in its dressage and driving competitions and the South African association followed suit last year.

If the international body, the FEI, and the larger national associations can be persuaded to review their rules, the bitless bridle could eventually be permitted in all equine sports. A proposal was being considered by the US Equestrian Federation as this issue of Veterinary Practice went to press.

“I don’t know whether they are ready to accept this change just yet but I am optimistic and feel we have reached a tipping point. But even if it doesn’t happen this time, I will still keep hammering away. I am 78 and may be getting on a little but I haven’t finished yet.”