Identification for on farm management

Examples of some systems used to individually identify pigs by marking their ears.

There are a variety of tracking and identification systems used for managing pigs. For herd management on your property there are a few ear-marking systems that can be used to identify individual pigs. The degree of detail used to identify the animals depends on the piggery's requirements ranging from a unique number for each pig to a number for each week/batch.

When each pig's identification mark and date of birth is recorded, the age of the animal can be easily calculated at any stage of its life. To be effective in the long term, most pig identification systems require a record book so you can easily trace the animals.

Benefits of identification

Keeping track of growth rates in a piggery is made easy by using a simple identification system coupled with a record book. This permits patterns of growth rates in a piggery to be graphed to reveal strengths and weaknesses in management.

Tracing a pig's age is important when selecting replacement breeding stock from within the herd. Average daily weight gain (growth rate) is calculated by dividing the liveweight of the pig by its age in days. This information is combined in an index with its backfat measurement and compared with information about its pen mates. This performance testing allows you to select faster-growing leaner pigs as breeder replacements.

Before moving pigs to sale or to an abattoir, as part of the National Livestock Identification System (NLIS) you must identify your pigs with a slap brand or approved ear tag registered to your property (ear tag not a slap brand if under 30 kg) and under Queensland's Brands Act, pigs over 30 kg must be slap branded with their registered tattoo (there are a few exemptions). NLIS enables the lifetime traceability of livestock. Lifetime traceability improves product integrity and market access (particularly for export markets), and assists with the management of disease and chemical residue issues. To move pigs you are also required to carry a Pig Pass, waybill or similar with all pigs, whether or not they are going for sale. See links at end of this article for further information about required pig identification.

Identification systems

Pigs can be permanently identified by notching or tattooing their ears. Numbered ear tags are also used but are not usually suitable for pigs penned together as the tags can be lost. Tags are more often used to renumber stock already identified by notching or tattooing e.g. newly purchased breeders. Ear tattoos are mainly used in landrace and large white stud herds and in some commercial piggeries. Even when correctly done, tattoos can be hard to read and use in everyday piggery management. Ear tattoo equipment (pliers and numerals) is more expensive than ear notching pliers and most commercial pig farmers find ear notching a suitable method of identification. Ear-notched pigs can be easily identified from a short distance and the notching remains visible for the life of the pig.

Ear notching

Ear notching is best done on piglets a few days after farrowing, at the same time as other procedures such as giving an iron supplement.

The notches must be carefully done so they can be easily read when the pigs get older. Notches at the base of pigs' ears need to be cut deeper than those nearer the tip, otherwise they may grow over in time. If notches are too near the curved base of the ear they could pass around the curve with age and be overlooked. On the other hand, notches clipped near the tip of the ear should not be too deep otherwise the tip of the ear may droop. This is especially likely to occur if the notches are close together as required in some systems. Shallow notches in this upper section of the ear are easily read. Ear notching should not be done too close to the head along the top of the ear or the ear may droop.

There are many ear notching systems in use and a few are outlined in figure 1. Basically, a position notched in the ear corresponds to a number. In some systems, notches are required close together (double-notching) in the same position.

The combination of numbers can:

  • identify a litter with the same number as their dam e.g. all piglets from sow number 51 would have that number notched in their ears.
  • identify a litter with its own litter number - one ear could be notched with the birth week number and the other with the order of birth in that week e.g. the fifth litter born in week 44 would be marked 44 in the left ear, 5 in the right.
  • identify each pig in the litter - this numbering system is used in research institutions and in some piggeries where individual pig performance is measured. One ear is notched to identify the dam, week or litter number, while the other ear shows a within-litter pig number.

Pigs are ear notched using specially designed pliers, which leave v-shaped notches in the ear. Ear notching pliers are available from some stock and station agents and from pig equipment specialists.

A diagram of the ear notching system used needs to be clearly displayed in the piggery so that all workers in the piggery can notch piglets correctly and 'read' numbers confidently.

Ear tattooing

The equipment required is a set of tattoo pliers, three or four sets of 9 mm needle blocks numbered from 0 to 9 and a suitable tattooing ink or paste. Similar systems of identification can be used to ear notching except that numbers rather than positions are tattooed in the ear. Before tattooing, ensure that both the pig's ear and the tattoo blocks are clean. The thinner part of the lower ear (inside or outside) is most suitable for tattooing. The needle points of the tattoo must be covered with tattooing ink; a toothbrush is useful for this, alternatively, dip the needle blocks into an ink-soaked pad. The needles should completely pierce the pig's ear, avoiding veins where possible. After tattooing, thoroughly rub ink into the puncture marks. The technique has to be carried out with painstaking accuracy to ensure the tattoo can be clearly read later. If you have trouble reading a tattoo number, try washing the ear or shining a torch behind it.

Ear tags

Once gilts and boars have been selected from within the herd or brought into it, they can be identified with easy-to-read numbered plastic tags. There are varying shapes and types of ear tags. Some tags are pre-numbered, others are supplied blank and can be numbered with a special pen. Several colour choices are available to increase coding possibilities. For example, animals with duroc parentage may be given red tags, while those with Hampshire genes may be given white ones with black numbers.

Tags are applied with special applicator pliers, usually in the front of the ear to reduce risk of the tag being torn out e.g. by fighting.

Electronic identification

The technology to identify pigs through electronic implants is already developed. An injectable radio transponder, which contains the pig's identification number, is implanted before weaning. The best site seems to be under the skin of the neck at the base of the ear. Alternatively, the transponder may be embedded in an ear tag. A receiver unit must be able to detect signals from the transponder at a distance of 30 to 60 cm from the pig, preferably without touching the animal. The number may be picked up on a portable receiver unit or stationary antenna at gates or fences. These units can then be attached to computers for information retrieval. The transponder is removed and destroyed after slaughtering the pig.

The system is costly if a large initial outlay is required, as computers, software, data communication and individual transponders are required. The investment is rewarded with accurate information for management purposes and positive identification at slaughter.

Computer-controlled sow feeding stations use electronic identification for feeding purposes. The sows wear a plastic collar, which is embedded with a radio transponder. When the sow enters the feeding station, signals received from the transponder trigger the station's feeding mechanism and the sow receives a measured amount of feed.


  • Pig identification is necessary for accurate performance records.
  • Pigs can be marked with ear notches, ear tattoos or ear tags.
  • Ear notching is the most practical method for commercial farms.
  • Ear tags are useful for re-identifying breeding stock.
  • Electronic identification, if it becomes cheaper, may be more widely used in the future.