Whenever we want to get to the bottom of a question regarding equine performance, welfare, nutrition or disease, we must consider the science. Scientists make it their life’s work to drill down on their areas of interest in an effort to answer all the questions they and their peers have in that area. The value of their work is tremendous: it guides us, shapes our understanding and, eventually, our behaviours and actions.
We should, however, be cautious and not focus too closely on a single aspect of a study area. We must first agree the papers presented are of a high standard, peer reviewed, with good experimental design and minimal opportunity for bias to skew the results.
In order to develop a bigger picture view, it is necessary to look at a whole body of work and preferably several studies showing that results can be repeated. Only when we have a big enough body of work can we weigh-up the findings of each individual study, and question whether some findings might outweigh the importance or validity of the others.
When we look at a complicated subject, such as the use of tongue ties in horses, strong feelings, beliefs and emotions often get in the way and, as the debate between industry and public opinion rages, scientists continue to test and produce work which might support either side of the argument, but more valuably, they add credence to the discussion.
Beyond that, we must combine current scientific findings with the more philosophical questions of ethics and values, so we can ask the ultimate question: “Where do our responsibilities lie?” The answer may well differ depending on whom or what we feel the greatest obligation to protect.
What is a tongue tie?
Tongue ties have been applied in equine sports for over a century. These days, they are commonly applied to Thoroughbred and Standardbred racehorses as a means to prevent the horse from putting its tongue over the bit. Tongue over the bit causes a loss of control and, in a racehorse that is running at full speed, the action and behaviours that result can impair the airway.
An impaired airway can, at best, cause a loss of performance and cost you the race, but it is also believed to cause what is commonly known as ‘choke down’ – a loss of consciousness, due to a lack of oxygen. It doesn’t take much imagination to visualise that, if this happens at full speed and amongst a group of horses also running at full speed, it could lead to a serious accident.
Although reported incidences of ‘choke down’ are rare, tongue over the bit is common in racehorses. Some might argue the low incidence of ‘choke down’ is because tongue ties are regularly used as a preventative measure but, before making such correlations, we must first collect data and examine the evidence.
There are also welfare concerns with the use of tongue ties. Indeed, the Veterinary Committee of the International Equestrian Federation (FEI) banned tongue ties in 2004 mainly because of concerns about the length of time they were applied for.
Anecdotes from people heavily involved in the racing industry include tales of horses being unable to eat for days following the use of a tongue tie during race or training days. Physical damage to the tongue, including lacerations, interrupted blood supply (blue tongue) and tongue paralysis are not unusual, and there are reports of permanent damage and tissue necrosis.
The regulations regarding tongue tie design, how tightly it can be applied and for how long is notably lacking on a worldwide scale. Track officials are also not monitoring or checking horses for damage after racing.
German Thoroughbred racing announced a ban on tongue ties in anticipation of the imminent implementation of a new welfare law that will cover all horses nationwide. But in the racing jurisdictions of other countries and certainly in Australia, many consider tongue ties an essential risk-management tool that can enhance, not just the individual horse’s performance, but everyone’s safety during the race.
Where safety aspects govern the regulators’ decision-making process, the burden of proving the equipment does or does not improve safety, and whether this effect outweighs welfare concerns, inevitably falls in the hands of the scientific community.
So, what does science have to say about tongue ties? Do they contribute to better airway function? Do they pose a significant welfare risk to horses? And, how significant are the welfare costs when weighed against the potential increase in safety, as well as earnings from enhanced racing performance?
Over the last decade or so, a very small number of research studies have been conducted regarding the use of tongue ties. Some have looked at their potential efficacy in cases of partial airway obstructions such as dorsal displacement of the soft palate or DDSP (where the soft palate becomes displaced during high intensity exercise to cover and partially obstruct the airway). So, let’s take a look at some of the most significant findings.
In 2013, the Equine Veterinary Journal published a study1 by Heather J Chalmers, which examined horses using a newly developed ultrasound technique to examine the internal structures of the upper airway.
Twelve Standardbred horses were examined at rest with and without a tongue tie applied. The method of application for this study was to extend the tongue forward as far as possible before tying it down and placing the tongue to the side of the lower jaw (see Image A page 60), using a commercially available tongue tie. (It is worthy to note that this extreme method of application is not the most common amongst Australian trainers.)
The researchers concluded, with the tongue tie applied, the horses’ upper airway structures were positioned in a way that was more compatible with upper airway stability, however, the results may not be representative since these horses were in a resting position and exercising can significantly change the positioning of the airway structures.
Despite not taking any physiological or behavioural stress measures, in an interview2, Chalmers commented the tongue ties did “not seem to bother the horses”. She commented further the use of tongue ties might actually represent an improvement in safety since they offer a greater degree of control.
This paper appeared to support the findings of a 2009 retrospective study presented in the Equine Veterinary Journal by Barakzai et al.3 which evaluated the racing performance in Thoroughbred racehorses in the United Kingdom via the national Racing Post Online Database.
One hundred and eight horses recorded to be running with tongue ties were evaluated by choosing 60 random dates from 2001 to 2003, and comparing performance against randomly selected control horses not wearing tongue ties.
The results showed horses wearing tongue ties attracted greater odds for ‘improvement’ when they wore the tongue tie for three to five consecutive races. For those individuals where a tongue tie was applied part way through the test period, a significant increase in earnings was noted once the tongue tie was applied. The researchers concluded the use of the tongue tie might have a beneficial effect on racing performance in a selected population of British Thoroughbred horses.
Both of these studies are weighted for the use of tongue ties as a performance enhancing tool and, viewed alone, suggest no concern regarding their use.
In 2002, The Equine Veterinary Journal Supplement, Equine Exercise Physiology, published a study by Franklin et al.4 looking at the use of tongue ties in horses with dorsal displacement of the soft palate (DDSP). In this study, the horses worked on a treadmill, so the efficacy of the tongue tie could be tested dynamically in a situation more similar to that in which the displacement might occur during training or racing.
Six Thoroughbred racehorses with confirmed DDSP were subjected to a high-intensity exercise test with and without a tongue tie applied. The tongue tie was a fabric strap placed over the tongue and secured to the bottom jaw. This method of application differed to the Chalmers study mentioned earlier. The horses were monitored for gaseous exchange (respiratory function), as well as endoscopic observation of the soft palate during the exercise test.
Without the tongue tie, all six horses displayed DDSP during the exercise test. With the tongue tie in place, four horses still experienced displacement during the high-intensity part of the test, with a fifth horse experiencing it at the end of the test during deceleration. The tongue tie was not shown to improve ventilation in those horses that still experienced displacement before or during displacement.
Considering milder displacements were not significantly reduced by the tongue tie, an interesting follow-up question, which is yet to be answered scientifically, is whether the tongue tie plays any role in preventing horses from reaching the critical ‘choking down’ scenario.
A previous study by Cornelis et al.5 in 2001 used five healthy Standardbred horses and applied the tongue tie in the same way as the Chalmers study.
Horses were measured on a high speed treadmill for airway function and gaseous exchange, as well as respiratory rate. This study failed to show any increase in respiratory function in normal healthy horses, but suggested that the tongue tie might be effective in assisting horses with a diagnosed upper airway obstructive condition such as DDSP.
A survey of racehorse trainers in the United Kingdom, Franklin et al. 20016 reported that conservative measures of treating DDSP, such as fitting tight nosebands and tongue ties were only completely effective in 12.9% of cases, with 42% saying they were partly or temporarily effective.
In summary, and in regards to respiratory performance, the available scientific literature shows that tongue ties have a positive effect on some horses and not others, and only when DDSP is present.
Despite this, there are many incidences of tongue ties being used when no diagnosis of DDSP has been confirmed. There are also surgical alternatives to treat and fix DDSP and other upper airway issues with good prognoses.
The question of why industry continues to recommend them could, therefore, be assumed to be fear driven – if there is even a slim chance of preventing a loss of control through tongue over the bit, then, perhaps for the trainer, it’s worth the trade-off of applying a tongue tie on the ‘just in case principle’.
The welfare considerations
During last year’s International Equitation Science Conference in Wagga Wagga, New South Wales, Australia, Dr Franklin presented a study by PhD candidate Laura Latimer-Marsh7, which tested the stress responses of horses fitted with a tongue tie at rest.
A United Kingdom study in 2016 by Pollock et al.8 had shown that young horses do not tolerate the tongue tie very well, and suggested that maybe a period of habituation was required for horses to become accustomed to the equipment. Part of Latimer-Marsh’s study was designed to test this hypothesis.
Twelve Standardbred horses – six of whom had prior experience of the tongue tie, and six of whom were naïve – were used to compare two treatments: Tongue tie or tongue manipulation. The parameters measured included commonly accepted behavioural and physiological indicators of stress.
For the horses in the tongue tie treatment, an elastic tongue tie was looped twice around the tongue and the lower mandible to secure the tongue in place. For the tongue manipulation treatment group, the tongue was manipulated for 30 seconds to mimic the application of a tongue tie without actually attaching one. Horses were then left for 20 minutes with or without the tongue tie, and parameters measured.
The horses with tongue tie application showed significantly more frequent behaviours indicative of stress (gaping, ears back, head tossing, etc.).
Time spent with ears backwards increased in the second part of the testing period, which may indicate that the longer the tongue-tie is in place, the more discomfort the horse may be experiencing. These behaviours were even more pronounced and frequent in those horses previously experienced with the tongue tie, and were less so in the naïve horses.
This last finding contradicts Pollock et al. study’s assumption, showing no indication that previous experience led to any sign of habituation.
In regards to physiological parameters, cortisol levels were shown to be higher in the tongue tie treatment group following its removal (indicating a stress response), but other biological indicators, such as heart rate and eye temperature, showed no significant differences.
This study was presented at a scientific conference and is awaiting publication in a peer reviewed journal.
The 2016 Equine Veterinary Journal reported a survey by Findley et al.9 of Australian racehorse trainers with questions about the use of tongue ties. Five hundred and thirty five trainers responded to the survey and 85% of respondents reported using a tongue tie.
Tightness and method of application varied, as did the type of tongue tie used amongst the trainers, but elasticated bands were the most popular. Trainers reported tongue ties were applied most commonly to prevent horses from getting their tongues over the bit (78%), with only 37% reporting use related to suspected upper airway obstruction.
Of concern is that 26% of trainers surveyed reported complications from the use of the tongue tie, including superficial cuts, swelling and development of head shyness.
If tongue over the bit is the trigger for fitting a tongue tie and there are welfare concerns regarding its use, is it possible to train horses not to draw the tongue back and over the bit at all?
This was the topic of an article in the May issue of Horses and People, where two world-renowned equitation scientists and experienced trainers, Dr Andrew McLean and Kate Fenner, agreed the root cause of tongue over the bit is man-made; the result of placing too much un-relenting, meaningless pressure on the horse’s tongue via the bit.
They argued, once the horses learn they will be rewarded with a release of bit pressure as soon as they respond correctly and provided the riders never sustain bit pressure for long periods – the horses soon learn to relax their tongues under the bit.
Bits with mouthpieces fitted to the individual horse’s oral anatomy to provide improved comfort and relieve pressure are also worthy of investigation. We will bring you more on this topic and advances to bit design in an upcoming issue of Horses and People.
The social licence to operate
The notion of ‘adding more tack’ to fix a problem created by poor horsemanship is quickly going out of fashion. Increased public awareness is challenging horse sports’ social licence to operate.
The recent ban of tongue ties in Germany comes as a result of public outcry following a scathing 45-minute TV documentary10 that focused on a number of welfare issues in Thoroughbred horse racing (including tongue ties). It triggered several meetings at ministerial level that led the Thoroughbred racing groups to issue a ‘non-negotiable’ and immediate ban on tongue ties across the nation.
In other countries and in Australia, however, the justification for continuing to use this equipment in racing relies on its perceived impact on the safety of the horses, jockeys and spectators.
While safety is unquestionably important, the safety impacts of banning tongue ties are being tested – right now – on Germany’s racetracks and deserve international attention.
Whichever the result, the more we learn about the psychology of our equine athletes, the more apparent it becomes the road to safety is best travelled by improving their welfare standards in all our interactions.
Equitation science has led the way in this area by establishing the First Principles of Horse Training11, which are underpinned by an understanding of horse ethology, cognition and learning theory, and a commitment by those involved to put the animal before the athlete – the horse’s welfare above performance.
If the only reason for using tongue ties routinely boils down to a perception of what might happen, and the data cannot, ultimately, be shown to support such fear, it should be deemed unreasonable.
Other factors, such as the impact the equipment has on the horse’s experience, should always be prioritised in the decision-making process.
In an age where the public eye is becoming increasingly more focused on the welfare issues surrounding animals used in sports and entertainment, we cannot afford to ignore welfare concerns.
There is simply not enough research to answer all the questions regarding tongue ties or to inform the regulatory bodies on the best course of action.
While the argument is always for ‘more research’, as our knowledge in the areas of welfare and equitation science increases, we are beginning to get a good understanding of the impacts of this and many other traditional training and management practices.
Evidence of the welfare costs of tongue ties and several other established practices, such as confinement, isolation, hyperflexion, over-tightening of nosebands and whip use, is mounting.
While there is a legitimate safety concern for horses racing at full speed in a group, the research to support the argument that the tongue tie contributes is far from conclusive, and the current German situation could be used to provide the necessary statistics.
In the meantime, the more pertinent question is: “Why do so many horses in the Thoroughbred and Standardbred racing industries run with the tongue over the bit, unless it is tied down?” And, “is there an alternative and benign solution to tongue ties?”
It is the industry insiders, those who are passionate about their horses, sport and lifestyle, who should initiate collaboration projects with equine and welfare scientists in a quest for viable alternatives that will benefit all involved – the people, the sport and the horses.
If better training and management skills can lead to a reduction of the incidence of tongue over the bit without the need for restrictive equipment, this will be the more ethical answer.
So far, the record shows industry still chooses to ‘cherry pick’ and support only the scientific findings that align with their established practices, and ignore the studies that question or call for change. Change is admittedly challenging, but in an industry which faces daily scrutiny on the public stage, change that benefits the horse is not only ethical, but the key to the sports’ sustainability.
It is hoped that, as the evidence becomes more robust and more scientists are encouraged to add their voices (and their findings) to the discussion, the blinkers – and perhaps the tongue ties too – will, at last, be removed.
List of references:
- Chalmers, H. J., Farberman, A. , Bermingham, A., Sears, W. and Viel, L. (2013), Laryngohyoid position with tongue tie. Equine Vet J, 45: 711-714. doi:10.1111/evj.12056
- Barakzai SZ1, Finnegan C, Boden LA. (2009) Effect of ‘tongue tie’ use on racing performance of Thoroughbreds in the United Kingdom. https://www.ncbi.nlm.nih.gov/pubmed/20095231
- Franklin, S. H., Naylor, J. R. and Lane, J. G. (2002), The effect of a tongue‐tie in horses with dorsal displacement of the soft palate. Equine Veterinary Journal, 34: 430-433. doi:10.1111/j.2042-3306.2002.tb05461.x
- Cornelis J. Cornelisse, DVM; Susan J. Holcombe, VMD, PhD; Frederik J. Derksen, DVM, PhD; Cathy Berney, BS; Cynthia A. Jackson, DVM (2001) Effect of a tongue-tie on upper airway mechanics in horses during exercise AJVR, Vol 62, No. 5
- Franklin, S.H., McLachlan, C. and Lane, J.G. (2001) The treatment of DDSP in Thoroughbred Horses in Training in the UK, 1999-2000. BEVA Congress Proceedings, Harrogate
- Latimer-Marsh L., Hazel, Santos L., McGreevy P., Franklin S., The effect of tongue-tie application on stress responses in resting horses. Proceedings of the 13th International Equitation Science Conference https://equitationscience.com/previous-conferences/2017-13th-international-conference.
- Pollock, P, Perkins, J, Kelly, P, Reardon, R (2016) Longitudinal overground endoscopy ﬁndings for conservative management of DDSP, European College of Veterinary Surgeons Annual Scientific Meeting ECV.’ Lisbon, Portugal.
- Findley J.A., Sealy H., Franklin S.H. (2016), Factors associated with tongue tie use in Australian Standardbred horses. Table of Contents. Equine Vet J, 48: 1-4. doi:10.1111/evj.12611
- The short life of racehorses. A film by NDR: https://www.youtube.com/watch?v=epwVOCEdd8o
- First Principles of Horse Training. https://equitationscience.com/equitation/principles-of-learning-thoery-in-equitation