Nose ring (animal)

A nose ring is a ring made of metal designed to be installed through the nasal septum of pigs (to prevent them from rooting) as well as domestic cattle, usually bulls. In pigs, nose rings are alternatively pierced through the rim of the nose. Nose rings are often required for bulls when exhibited at agricultural shows. There is a clip-on ring design used for controlling and directing cattle for handling. Nose rings are used to encourage the weaning of young calves by discouraging them from suckling.
History.
Historically, the use of nose rings for controlling animals dates to the dawn of recorded human civilization. They were used in ancient Sumer and are seen on the Standard of Ur, where they were used on both bovines and equines. There are theories that the rod-and-ring symbol are a shepherd's crook and a nose rope.
Use.
The nose ring assists the handler to control a dangerous animal with minimal risk of injury or disruption by exerting stress on one of the most sensitive parts of the animal, the nose. Bulls, especially, are powerful and sometimes unpredictable animals which, if uncontrolled, can kill or severely injure a human handler. 
Control of the bull may be done by holding the ring by hand, looping a piece of rope through it, clipping on a bull staff. A rope or chain from the ring may be attached to a bull's horns or to a head-collar for additional control.
With an aggressive bull, a short length of chain or rope may be left hanging loose from the ring, so when he ducks in a threatening manner, the bull will step on the chain and be deterred from attacking. This lead may also facilitate capture and control of a frisky bull.
Construction and insertion.
Bull rings are usually about in diameter, depending on the size of the bull. Bull rings are commonly made from aluminium, stainless steel or copper, in the form of a pair of hinged semicircles, held closed by a small brass bolt whose head is broken off during installation. If a ring needs to be removed (for example, if the bull has grown out of it), it is cut or unscrewed. 
The ring is normally placed on the bull between 9 and 12 months of age. It is usually done by a veterinarian, who pierces the septum with a scalpel or punch. Self-piercing rings (with sharp ends designed to be pressed through the septum and then pulled together with a screw) have been available for many years; these are also usually installed by a veterinarian rather than the owner.
Other designs.
Calf-weaning ring.
Calf-weaning nose rings or nosebands provide an alternative to separating calves from their mothers during the weaning period. They have plastic spikes which are uncomfortable for the mother, causing her to reject the calf's efforts at suckling. Weaning nose rings are also available for sheep and goats. These nose rings (usually made of plastic) clip onto the nose without piercing it, and are reusable.
Bulldogs.
Self-locking or spring-closing show-lead nose rings, also called "bulldogs" or nose grips, are removable rings that do not require the nose to be pierced. They are often used on steers and cows, along with a halter, at agricultural shows, or when handling cattle for examination, marking or treatment. They stay shut until released, and usually have a loop for the attachment of a cord or lead rope. They give similar control to a bull ring without the need for permanent attachment. 
Bull tongs.
Bull-holders, also known as bull-tongs, have a pliers action and are used for short periods on grown cattle when they are being mouthed or drenched. A chain, rope or strap keeps the grips closed and may be passed over a bar at the front of a head bail to elevate the head. The thumb and forefinger may also used in this way on smaller animals.
Pig nose rings.
Rooting is the act of a pig nudging into something with its snout, such as into the dirt to unearth plants to eat. In some circumstances, owners of pigs may find this undesirable. Nose rings make rooting painful for the animal, although a ringed pig may still able to forage freely through leaf litter and surface vegetation. Pig nose-ringing may sometimes be required by local regulations, as when farm pigs are released into public woods to pannage (such as on the New Forest in southern England).
Nose rings specifically designed for pigs usually consist of open copper or steel wire rings with sharp ends, about in diameter. These are typically clipped to the rim of the nose instead of through the septum, as this is far more painful to the pig and is considered "thus more effective for deterring the pig from rooting than piercing through the septum is". As they may sometimes become dislodged, an adult pig may be given three to four rings.
Bull handling in the show ring.
For safety reasons, many show societies require bulls over 12 months to be led with a nose ring. A bull may be led by a rope tied through the ring, although a halter (headcollar) is usually also used so as not to rely unduly on the nose ring for control. If the bull has horns, the lead rope may also be fastened around those and then passed down through the nose ring. Some shows require other cattle to be led with nose grips (bulldogs). Several methods exist for handling a bull with a ring installed. One method of leading a bull is to have one person on either side of the bull with both halter lead ropes through the ring, which prevents the bull from gaining pace and also from running into the handlers. Another practice is for one handler to use a rope and the other a bull-staff attached to the ring.
Bull handling on the farm or ranch.
It is estimated that 42% of all livestock-related human fatalities are a result of bull attacks, and only about one in twenty victims of a bull attack survives. Dairy breed bulls are particularly dangerous and unpredictable; the hazards of bull handling are a significant cause of injury and death for dairy farmers in some parts of the United States. Most cattle breeders recognize the importance of looking after expensive bulls that are expected to improve herds and profits. Nonetheless, the dangers of bull handling, particularly from dairy bulls in close quarters, are regularly proven by the obituaries. Good bull management and safety practices require caution in handling beef and dairy bulls, and use of the nose ring and chain is a recommended precaution for modern farmers.
However, in many regions, particularly in the beef industry, bulls do not have nose rings unless they are to be exhibited and they are generally driven about as other cattle would be. Cows with young calves can be particularly dangerous if protecting their young, and cattle in general, including calves, steers and bullocks, do cause many serious human injuries and deaths.
Generally the use of both a ring and a halter, and management of the bull by two people, is the preferred method today for controlling the bull. Typically, a bull was led by a wooden staff with a steel end that snapped into the ring. A long rigid steel or wooden bull staff locked into the ring could also be used to push a bull out of a pen without requiring the handler to enter the pen for cleaning or feeding. Because of the risk that the bull may drive the staff into the handler if the bull misbehaves many handlers prefer to avoid their use nowadays. One current veterinary text still recommends the use of a staff in addition to the halter: Many handlers rely on a nose ring to control a bull. But a ring in his nose is no good unless you have a bull staff and use it. A bull staff is a pole with a snap in the end that clips to the bull ring. Leading a bull with a staff gives you a lot more handling power as the bull can't get any closer to you than the length of the staff allows. Leading him only by a chain in the ring lets him run over you at will.
Most dairy or beef farms traditionally had at least one, if not several, bulls for breeding purposes. The handling of an aggressive, powerful animal was a practical issue with life-threatening consequences for the farmer. The need to move the bull in and out of his pen to cover cows exposed the farmer to serious jeopardy of life and limb. Being trampled, jammed against a wall or gored by a bull was one of the most frequent causes of death in the dairy industry prior to 1940. As suggested in one popular farming magazine, "Handle [the bull] with a staff and take no chances. The gentle bull, not the vicious one, most often kills or maims his keeper." 
When allowed outside his pen, the bull typically was kept in a halter connected by a strap snapped into the ring in his nose for ease of control. In the bull pen, the use of a ring connected by a cable to a fixed point was recommended as a means of controlling and securing the bull while allowing a degree of movement by the subject bull. If the pen was strong enough, the bull could be turned loose, and if needed, placed in a stanchion. Farmers who lacked an assistant, or a bull staff, had no choice but to adopt other means. Some farmers elected to move their bulls by tying a rope to the ring and tying the other end of the rope to a farm tractor, providing both motive power and a degree of protection from the angry bull. The efficacy of this technique is doubtful, and may depend on the size of the tractor and of the bull; one authority has "seen a bull lift the front end of a tractor like a toy". Others used dogs and horses. Not all farmers could afford specially designed and manufactured bull handling products, which were not readily available until the 1980s. The experimental improvisation of techniques for bull handling, as in many aspects of family farming, was a common practice.