The affects of noseband pressure *H&H VIP*

Last month’s feature (Don’t take it on the nose, 19 January) highlighted the importance of a correctly fitted noseband, outlining how various models can enhance a horse’s way of going and allow the rider greater precision and control.

A noseband also has the potential, however, to cause pain, to damage sensitive tissues and to prevent normal behaviours.

Tightness has been a focus of the recent concern among veterinary and equine welfare researchers, particularly as some nosebands are now designed to allow maximum tightness to be achieved with less effort. An example is the crank cavesson, frequently seen on dressage horses with a double bridle.

Two separate studies, carried out in Austria and the UK, have found that the tighter the noseband, the more sensitive the horse is to bit pressure. If the goal of tightening the noseband is to reduce or prevent the mouth opening, the consequences for the horse are important to consider.

Recent research from Australia showed that a very tight noseband prevents the horse from chewing and licking and reduces the frequency of swallowing. The same study found higher heart rates and eye temperature when the noseband was extremely tight. These responses suggest that the tight noseband was causing distress.

Unfortunately, we cannot ask the horse how stressful it is to not be able to chew, lick or swallow — but these are factors that we must take into consideration if we allow or use extremely tight nosebands.

Under pressure

Nosebands apply pressure around the horse’s face and also at the poll.

A UK research team placed pressure mats beneath the noseband strap in these areas. They found that the pressure was concentrated where bone lies close to the skin, so over the wings of the atlas bone (where the base of the skull meets the spine), at the poll, and over the nasal bones on the face.

Further research that I led in Ireland, using individual pressure sensors placed at different locations beneath the noseband, found similar levels of pressure. Using a Bluetooth wireless system, our research group recorded changes in pressure when horses were being ridden.

Pressure levels were highest during any events that resulted in the horse opening his mouth, but also during head and neck extension, such as during upward transitions, jumping or during any headshaking. The pressures measured were much higher when the noseband was fastened more tightly.

This research shows that the horse is experiencing regular and frequent pressure pulses against facial structures throughout ridden exercise, and that these levels of pressure will be much higher if the noseband is tight. Unfortunately, horses have evolved not to show pain in many circumstances where injury may exist. This makes it difficult to identify when the horse is in pain.

Lacerations to the inner cheek tissue, thought to be caused by it being pushed against the sharp outer edges of the premolar teeth by tight nosebands, are a regular finding in intra-oral exam by vets and EDTs (equine dental technicians).

In many cases the horse has shown minimal behavioural change. In some instances, the rider may detect changes in the horse during ridden exercise, such as headshaking, increased attempt at oral behaviours like chewing, licking or mouth opening, or extreme behaviours, such as napping, bucking or rearing.

The response of a horse to an excessively tightened noseband can be apparent acceptance, where the horse carries out fewer efforts at opening the mouth or other comfort seeking behaviours. This will occur if the consequence for the horse of opening his mouth is even more painful than keeping his mouth closed.

Some horses will, however, become more restless in response to pain, and will carry out behaviours that may be related to the flight response. This may manifest as tension, raised head and neck and increased speed. Teeth-grinding and tail-swishing could also be related to mouth pain.

Testing times

Since the 1950s, many textbooks have recommended that it should be possible to slide two fingers beneath a closed noseband.

A plastic taper gauge was developed by the International Society for Equitation Science (ISES) in 2012 to allow riders to do this easily, using an average measurement of two adult fingers as the guide.

The recent Irish research investigating the use of nosebands by competition riders showed that only 7% of nosebands were fastened at this level, with the remainder much tighter. The study revealed that 44% were too tight to allow any measurement gauge to be introduced beneath the noseband at the front of the face.

The high percentage of horses wearing extremely tight nosebands suggests that this has become a custom, rather than a practice based on an actual need, for at least some riders.

While more research is required into the effect of such tight nosebands on the underlying tissues, it is important to remember that skin, bone, muscles, nerves and blood vessels run directly beneath the noseband. In areas of prominence, where the face bulges towards the noseband (such as the nasal bones, the lower jaw bones and the bulge of the teeth at the sides of the face), pressures will be extremely high.

The Irish research team, based at Limerick University, found transient pressures at these locations which were four times the level of those that have been shown to cause damage to nerves and other tissues (and high levels of pain in human patients), when the pressure was sustained.

Further research is required, but, until the remaining questions have been answered, it is important to progress cautiously and to err on the side of safeguarding the welfare and safety of both the horse and rider.

An excessively tight noseband may give the impression of greater control, but could be the cause of undesirable problem behaviours as the horse attempts to escape pain or discomfort during exercise.

It may also be preventing the horse from carrying out normal behaviours, which may be important indicators of discomfort, and which may help the horse cope with the training methods and equipment used.

What next?

Regulation of noseband tightness in competition has been minimal because, in the absence of sufficient research, it has been difficult for evidence-based regulations to be drawn up and implemented.

While the FEI still recommends that a physical check by a steward is the safest way of ensuring that nosebands are fitted correctly and are not having an adverse effect during competition, findings show that this approach is of virtually no value in assessing pressure on more prominent structures such as nasal bones and jawbones.

Researchers continue to focus on this issue and are producing evidence that should persuade governing bodies that excessively tight nosebands are unacceptable.

Ref Horse & Hound; 17 February 2017