Studs or Screw-in Calks are traction devices screwed into the bottom of a horse shoe.
Use of studs
Stud improve a horse's balance and grip over uneven or slippy terrain, and can make him move better and jump more confidently in poor footing. The shoes are "tapped," or drilled, on either heel of the shoe, so that different studs may be applied as needed and changed according to the footing conditions and the type of work performed by the horse. Therefore, a horse may have a maximum of 8 studs (2 per foot). Studs come in several sizes and types.
Studs should be removed when the horse is not working, and the hole for the stud should be plugged with cotton, rubber plugs, or a stud blank, so dirt does not ruin the threads of the hole. A horse should never be shipped in studs or left in his stall with stud screwed in.
When used, a horse should always wear bell boots to protect himself, should he scrape himself with the bottom of his hoof, and brush or galloping boots are also advisable. It is best to only use pointed studs, such as grass studs or pointed bullets, on the outside of the shoe, so the horse is less likely to cut himself should his foot hit one of his legs. A road stud should be used on the inside. However, the shoe should have some stud on the inside of the shoe; without it, there will be a twisting motion on the foot, which can cause a loss of shoe, and possibly strain the legs. Most riders place smaller studs on the front feet, because the horse, being a "rear-engine" animal, generally requires more traction behind.
Choosing a stud
It is important to know which stud to apply, as the wrong stud will be useless and can damage the horse's legs. Too little traction, and the horse may slip and possibly fall. Too much, and the horse is jarred, as his feet cannot naturally slip (which is a shock-absorption mechanism). Additionally, the more stud used, the greater chance the shoe may be pulled off. When in doubt, it is often best to slightly understud. It is best for a rider to learn how to apply and choose studs from their trainer or farrier.
In general, the faster the pace, the larger the stud will be used. Therefore, small studs are used for dressage and lower-level jumping or eventing, and larger studs are used for polo and upper-level eventing. Studs with more of a point are used for hard ground, and those that have more circumference are used in "heavier" footing, such as thick mud.
Types of studs and other equipment used
|Road studs||used on hard surfaces, usually 4 or 6-sided, smaller in size and blunt. Can be used front or back, on the inside of the shoe or the outside. This type of stud is fine most of the time, unless the ground is incredibly muddy or slippery.|
|Blocks||square in shape and best for soft, deep, muddy ground.|
|Bullets||best for firm ground with a layer of soft ground on top. They are large and sharp.|
|Grass Studs||narrow and sharp to dig into hard, dry ground. They should only be used on the outside of the shoe, or just on the hind feet.|
|Olympic studs||used for extremely slippery ground, very long and sharp.|
A metal pick or horseshoe nail can help remove the plug prior to studding. A special instrument called a "T-tap" is used to clean out the stud holes before the stud is screwed in, or it can be used to re-tap the stud hole if the threads are damaged, although this process is usually tedious. When cleaning the stud hole with a tee-tap, it is advisable to screw it into the shoe for one full turn, before unscrewing it for one-half turn, to help the dirt and debris lift out of the threads. This should be continued until the shoe lifts slightly off the hoof, to ensure that all the threads were cleaned. Additionally, a small metal brush can be used to help clean threads which are especially dirty. A wrench is used to tighten or loosen the studs.