Alongside our seat and legs, the reins allow us to communicate with our mounts. To get the very best from the relationship, the communication needs to be transmitted clearly, concisely and without pain.
The reins communicate through pressure exerted on the bars of the mouth (lower interdental space), lips, tongue, hard palate, chin, nose and poll. The distribution of pressure depends on the bit, bridle and accessories used and the range of options available, is vast. Through schooling and correct choice of equipment, the horse should recognise the rider increasing rein pressure and respond to it, before significant pressure is applied. To achieve this, horses require a pain-free mouth, to be free from performance limiting diseases and ridden in suitable equipment through which they can understand their rider’s instruction.
Regular dentistry is fundamental to communication without pain. The grinding surface of a horse’s cheek teeth are sloped at 15-30o from horizontal and are ridged to increase the surface area. Sharp enamel points develop on the ridges, along the buccal (cheek) aspect of the upper teeth and the lingual (tongue) aspect of the lower teeth. These are exacerbated by uneven wear patterns, which are very common. Any pressure applied over a sharp enamel point on a tooth will cause pain and damage the lining of the mouth resulting in ulcer formation.
Each horse’s mouth is slightly different. Size of tongue, height and shape of palate, length of bars, depth and curvature of the jaw… and we ask them to perform different tasks, for which different head carriage and equipment may be required or appropriate. When performing the dental examination, we consider the horse’s conformation and what they are used for, so that we can maximise comfort and performance. This requires a level of compliance from our patients, as excessive movement limits effectiveness; therefore, we commonly use sedation for dental treatments.
Performance limiting diseases
When performance problems develop, a thorough oral examination is an excellent starting point, however other conditions may mimic bit pain, for example head shaking, gastric ulceration, proximal suspensory/distal hock pain. A thorough history and examination may raise suspicions of other disease processes which may be preventing your horse from reaching its potential. It is always worth discussing your performance concerns with your veterinary surgeon.
Bits (a brief overview)
The range of bits available now is a little overwhelming, so after researching what is allowed in your chosen discipline, there are 2 main areas to focus on, the mouthpiece and the cheeks.
These come in a range of materials, different metals, usually designed to encourage salivation and plastic or rubber coated, to provide comfort. Bear in mind, some metals rust and plastic can be chewed and become sharp, so may need regular replacement. Wider diameter mouth pieces are generally kinder but may overwhelm a small mouth. A narrow mouth piece can look elegant but may be harsh in inexperienced hands.
Solid mouth pieces can be straight, curved or ported and place most of the pressure on the tongue. Straights are more severe than Curves, which give a little tongue relief. Ports relieve tongue pressure and are generally milder, unless the port is high enough to contact the hard palate.
Broken mouthpieces contain one or more joints. The joints relieve pressure on the tongue by forming a roof over it and alter the angle of pressure from the reins, transferring it to the bars and lips. The position of the horse’s head, when rein pressure is applied, also affects the action of these mouth pieces, so will depend on the horse’s use. Double joints are generally less severe, unless they have a square- edged, central plate which acts vertically on the tongue (sometimes termed a Dr Bristol). Shaped-jointed mouth pieces (such as Neue Schule) avoid contact with the palate and are designed for comfort.
Waterford mouth pieces consist of jointed balls, which prevent the horse from leaning into the bit or getting hold of it. These are popular in show cobs, with heavy necks, encouraging lifting and softening.
The snaffle transmits pressure directly from the reins to the mouthpiece without enhancement and is the most common starter bit for young horses and inexperienced riders. Loose rings are the softest but may pinch the corner of the lip. Prongs attached to the ring (full or half cheeks) encourage the horse to turn and prevent the bit sliding through the horse’smouth if he resists. They are particularly good for children, who struggle to reinforce their rein aids with their legs effectively.
Leverage bits (Pelhams, Kimblewicks, doubles) have extensions above and or below the mouthpiece. These amplify the pressure from the rein, the strength increasing with the length of the extensions. Extensions above the mouth piece (which attach to the cheek piece) act on the poll, extensions below the mouth piece (attaching to the rein), lift the head and prevent leaning. The amount of rotation of the bit is usually checked by a curb chain, which spread the pressure through the chin groove. Correct fitting and use of these bits is essential, they allow fine control but can be harsh.
An intermediate between these two are the hanging snaffles, Wilkies, Cartwheels etc, which provide some leverage, encouraging horses to bridle, but without the enhancement of extensions, making them mild and suitable for less experienced riders.
Gags are the strongest form of leverage bit and should be used by experienced riders. They can be very helpful for strong horses, those that tend to go on the forehand or have a low head carriage. The main draw back is they can encourage overbending but use with a snaffle rein can prevent this.
Double bridles provide ultimate control but should not be introduced until a horse is going correctly in a snaffle. They require training of the horse and rider and must be fitted correctly to avoid injury.
Cavesson nosebands simply stabilise the bridle and provide attachment for leading reins or martingales. Dropped, Flash and Grackle nose bands stabilise the bit and prevent the horse opening its mouth to evade bit pressure.
Bitless bridles can be a suitable alternative for horses with damage to the tongue or bars, the Hackamore is the most common but there are many options. These are not necessarily mild, using the poll, cheeks, nose and chin pressure, often with lever action. Regular dental care is equally important for horses ridden in bitless bridles and correct fitting is key to function.
Generally, when making decisions on tack, start simple and go from there; use all the resources available to you: your governing body, trainer, vet and of course, listen to your horse.