Identifying pigs
Geoff Pollock (former staff member of DPI&F) (original by former staff member Larissa Dann)
Summary
- 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.
Introduction
This note outlines systems for identifying individual pigs by marking their ears. 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 that details of the animals can be later traced.
Tracing a pig's age is important when selecting replacement breeding stock. 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 faster growing, leaner pigs to be selected as breeder replacements. Keeping track of growth rates in a piggery is made easy if a simple identification system is coupled with a record book. This permits patterns of growth rates in a piggery to be graphed to reveal strengths and weaknesses in management.
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 trimming teeth and tails and giving iron.
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 deeply, 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.
Figure 1. Ear notching systems
The combination of numbers can:
- identify a litter with the same number as their dam e.g. all piglets on 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 (see figure 2). 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 workers can notch piglets correctly and 'read' numbers confidently.
Ear tattooing
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. These are obtainable from equipment suppliers but are expensive compared with notching pliers. Similar systems of identification can be used to ear notching except that numbers rather than positions are tattooed in the ear. Figure 3 illustrates ear tattooing pliers and a sample imprint of the tattoo needles. 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 (see figure 4). There are varying shapes and types of ear tags: some are pre-numbered, others are supplied blank and can be numbered with a special pen. Several choices of colour 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 eg 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 slaughter of 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 in which is embedded 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.
Further information
If you require further information about pigs:
DPI&F Business Information Centre from 8 am to 6 pm weekdays: Phone 13 25 23 (Queensland residents), non Queensland residents phone +61 7 3404 6999; e-mail callweb@dpi.qld.gov.au
DPI&F's web site www.dpi.qld.gov.au
As well as being published on DPI&F's pig industry web site at www.dpi.qld.gov.au/pigs/, this DPI&F Note will be published on the DPI&F PrimeNotes CDROM and will be published on DPI&F's national Pig Technotes CD.
Information contained in this publication is provided as general advice only. For application to specific circumstances, professional advice should be sought. The Department of Primary Industries and Fisheries has taken all reasonable steps to ensure the information in this publication is accurate at the time of publication. Readers should ensure that they make appropriate inquiries to determine whether new information is available on the particular subject matter.
Last revised 31 October 2004
