There has been a lot of talk about the horses’ tongues and mouths recently, ranging from the Adreas Helgstrand documentary to Patrick Kittel’s horse repeatedly showing a blue tongue in competition. After the 2024 World Cup Finals in Riyadh, a Eurodressage-article also presented multiple photographs of top-level horse-rider-combinations, where the horses clearly have their mouth open – possibly (probably) trying to avoid the pressure from the double bridle and the rein-induced pressure of the bit in the mouth. Admittedly, there have been some comments suggesting that the photographs used in these articles were allegedly edited. On the other hand, there are plenty of other similar pictures found of the same riders, which shows that the issues persist.
Even though I personally find it very sad, if the level of riding currently on display truly represents global top-level riding, I want to focus on the anatomical importance of the mouth and tongue, not only for equine welfare, but also on the biomechanics of the horse. It seems that the discussion on equine welfare has become very negative and accusatory in tone, which I don’t think is the right approach – the horses don’t benefit from it. My aim is to provide knowledge so that everyone can make an educated opinion about horses and their welfare themselves. I consider it crucial that research and practical management work together rather than against each other. Currently, this doesn’t seem to be the case.
Mouth Problems
The mouth problems persist across disciplines in the equine industry. They are not limited to dressage, show jumping, cross-country, or other ridden disciplines. For example, the use of tongue-ties is common especially in horse racing – both in ridden and harness racing. Also, a significant number of mouth lesions were found in harness-racing horses in Finland in 2021: 84% of all examined horses had acute lesions[1]. In cross-country horses, 52% showed acute lesions [2].
Why are we so passionate about this? Well firstly, lesions are wounds, and they shouldn’t be present in an equine mouth. It is quite clear that the formation of these lesions is painful for the horse. Secondly, there seems to be lack of anatomical understanding or implementation of possible knowledge when it comes to bits and bridles.
Pic: M. Lüscher
The anatomical aspect
The tongue is attached to the hyoid bone, which is a part of the hyoid apparatus. The tongue is thus directly connected to the poll and the front legs, but also indirectly to the abdomen, back muscles and hind quarters (see illustration here). At the end of the day, every muscle in the horse’s body connects to the hyoid in some way. This is why it’s so important to realize, what an effect the tongue and mouth has on the horse!
Restricting the function of the mouth and the tongue also restricts the movement of the limbs, the back, and the abdomen – all parts of the body the horse needs for true collection. For a horse to be able to use its body and to collect itself correctly, it must be able to use its mouth and tongue in a relaxed and flexible way. A correct use of bits can be used to improve the movement of the horse. This requires a lot of knowledge and feel. Currently we are seeing “collection” that is not biomechanically sustainable or natural for the horse. This new trend might be possibly linked to the increasing number of mouth issues we see in horses.
There are beautiful illustrations on this subject on the pages of onlinepethealth, Maria Cooke, or Vet Physio Phyle. I also recommend the e-book CVM Large Animal Anatomy from the University of Minnesota, which is accessible to everyone.
Bits
Restrictions of tongue movement can be caused by tongue ties, bits, or nosebands. Understanding how bits work, is essential, so we can understand the effect they have on the tongue. Basically, depending on the style of the bit, rein pressure induces pressure directly on the bit, or also on the headpiece when the bit is shanked and thus leveraged.
This pressure is transferred on the tongue and/or the palette and bars. When there is pressure on the tongue, the horse can experience pain and discomfort and have difficulties swallowing. This, in turn, may cause stiffness in the mouth and thus in the whole body. Pressure on the tongue can also interfere with the blood circulation in the tongue and eventually turn the tongue blue. When blood circulation is interrupted, tissue damage can also occur.
Additionally, there are indications that horses are more content and have a better horse-human-relationship, if bits are not used while riding [3]. This does not mean that bits mustn’t be used, and according to the study [3], the main reason for the contentment was that the horses ridden without a bit had received more training from the ground. You can find more information here.
The subject of bits could be discussed further, but for the sake of this article, it’s important to understand that putting pressure on the reins also causes pressure on the tongue, which can cause issues in the whole horse’s body.
Tongue ties
Tongue ties, mainly used in racehorses, can also cause tissue damage and blood flow problems, when used incorrectly of for too long. Germany has banned the use of tongue ties in Thoroughbred racing, and according to the RSPCA, in Australia tongue ties are only allowed 30 minutes prior to the race and must be removed as soon as possible afterwards. In FEI competitions tongue ties are prohibited.
In Finland the new suggestion for the equine welfare regulation proposes that tongue ties could only be made out of fabric or leather. Some countries still use rubber, which increases the risk for tissue damage profoundly. Using tongue ties in cold environments should also be avoided due to the high risk of blood flow issues and tissue damage. Studies also show that using tongue ties can cause pain, anxiety, distress, and difficulties swallowing [4].
Tongue ties are mainly used so that horses don’t choke on their own tongues, or to prevent airway obstruction during intense exercise[5]. This has been the case in some horses, as studies show, and there is evidence that tongue ties have a positive effect on upper airway function [5]. However, in newer studies and for most horses, that don’t have issues with their palette and airways, tongue ties don’t enhance the upper airway function. Still, some increases in performance in Thoroughbred racing have been documented in the UK [5]. Most equine welfare advocates don’t encourage using tongue ties due to the pain, stress, and discomfort that they can cause on the horse. If there’s a risk of dorsal displacement of the soft palate in a certain horse, the necessity of a tongue tie should be discussed with a veterinarian.
Summary
Usually, when the horse opens its mouth while riding or exercising, it is trying to decrease the pressure from the bit and the reins. The rider or handler should react quickly and have a very sensitive feel to the horse’s behavior. A study shows that sadly, many equestrians don’t recognize mouth-pain induced behaviors in horses [6]. That is probably also why mouth problems have become such a significant issue. It is also important that people in the industry realize the effect of tongue function on the whole body of the horse. If we want true collection, we can’t have it when we force it with reins. That is anatomically just not possible.
References
[1] K. Tuomola, N. Mäki‐Kihniä, A. Valros, A. Mykkänen, and M. Kujala‐Wirth, “Risk factors for bit‐related lesions in Finnish trotting horses,” Equine Vet J, vol. 53, no. 6, pp. 1132–1140, 2021, doi: 10.1111/evj.13401.
[2] K. Tuomola, N. Mäki-Kihniä, A. Valros, A. Mykkänen, and M. Kujala-Wirth, “Bit-Related Lesions in Event Horses After a Cross-Country Test,” Front Vet Sci, vol. 8, 2021, [Online]. Available: https://www.frontiersin.org/articles/10.3389/fvets.2021.651160
[3] K. L. Luke, T. McAdie, A. K. Warren-Smith, and B. P. Smith, “Bit use and its relevance for rider safety, rider satisfaction and horse welfare in equestrian sport,” Appl Anim Behav Sci, vol. 259, p. 105855, 2023, doi: 10.1016/j.applanim.2023.105855.
[4] L. Marsh, P. McGreevy, S. Hazel, L. Santos, M. Hebart, and S. Franklin, “The effect of tongue-tie application on stress responses in resting horses,” bioRxiv, p. 634717, Jan. 2019, doi: 10.1101/634717.
[5] A. K. Barton, A. Troppenz, D. Klaus, I. Lindenberg, R. Merle, and H. Gehlen, “Tongue ties do not widen the upper airways in racehorses,” Equine Vet J, vol. 55, no. 4, pp. 642–648, Jul. 2023, doi: https://doi.org/10.1111/evj.13867.
[6] D. J. Mellor, “Mouth Pain in Horses: Physiological Foundations, Behavioural Indices, Welfare Implications, and a Suggested Solution,” Animals (Basel), vol. 10, no. 4, p. 572, 2020, doi: 10.3390/ani10040572.
