How do EID  tags and tag readers work

Electronic Identification (EID) is the use of a microchip, or electronic transponder, embedded in a tag to identify a farm animal. EID in animals is based on low-frequency radio waves or Radio Frequency Identification (RFID). A reader sends out a radio signal which is picked up by the microchip. The chip sends back the unique identity number. The reader transfers the unique number to a computer which uses it to store whatever information is necessary about the animal being identified

Why use EID & what are the benefits

Tagging animals with an electronic (EID) tag provides an opportunity to better manage the individual performance of those animals.

Over time, an animal’s weight history can be tracked, good and bad performers can be identified and the input of resources managed to ensure profits are maximised.

Tru-Test EID readers deliver information about your livestock rapidly, by reading electronic ear tags on animals that are on a weigh platform or running through a race. Individual animal information captured against EID tags can help inform your animal health, mating and culling decisions. All Tru-Test EID readers are rugged, reliable, 100% water and dust-proof. Suitable for cattle, sheep, pigs and deer applications. Farm management practices can be greatly improved through the use of EID systems.

Benefits of EID include:

  • less paperwork or transcription is required thus improving ease, speed and accuracy of data collection
  • no direct animal contact is necessary to achieve accurate identification thus improving speed and safety of handling
  • direct transfer to PC, reducing time spent transcribing collected data
  • PC based management software allows powerful analysis of data to provide management information on which to base decisions relating to performance
  • improved information flow allows more objective and timely decisions thus improving performance

In this blog we break down the benefits for each livestock group, sheep, cattle and dairy cows and calves.


Initial Department of Agri proposals, which have been seen by the Farming Independent, indicate that electronic cattle tags will be made available to all livestock farmers from October 1 this year.

The Department’s plans envisage that all newborn calves would be EID tagged from July 1, 2022.


The Department pointed to a number of benefits that could flow from the introduction of EID tagging of cattle. These include

  • Improved traceability as the scanning of EID tags facilitates automated reporting of animal movements
  • Improved accuracy, reliability and speed of data capture/transfer;
  • Reduced administrative burden including the elimination of animal and passport mismatches and amendments
  • Efficient use of time and labour
  • Greater safety around the reading of tags
  • Monitor average daily gain and body condition on an individual animal
  • Accurately administer treatments and antibiotics
  • Faster throughput of animals when auto weighing, drafting, feeding, etc with EID tags
  • Identify poorly performing animals early on and make better breeding decisions.

Beef Cattle Weighing & EID

Contact Rearing Dairy Calves with EID



Many farmers are doing away with manual sheep identification in favour of EID tags. If you’re still on the fence about whether or not you should make the switch you’re probably wondering what the advantages of this new technology are.

EID tags eliminate mistakes and ensure all the information you collect is 100% accurate.

These include:

  • Improved traceability as the scanning of EID tags facilitates automated reporting of animal movements
  • Improved accuracy, reliability, and speed of data capture/transfer;
  • Reduced administrative burden including the elimination of animal and passport mismatches and amendments
  • Efficient use of time and labour
  • Better Individual Animal Management (Precision Sheep Management
  • Better Breeding Stock Selection

EID tags are the way of the future. By utilizing this technology you’ll not only run a more efficient farm, but you’ll also contribute to the overall success of the entire sheep industry.

Sheep EID

The advantages that the use of EID brings in terms of increasing flock performance far outweigh the financial costs of applying tags and owning a reader – especially when tagging lambs at birth and when used proactively to record animal movements, weights, medicinal records, and more, it comes with some major benefits that result in less paperwork and administrative errors, and more efficient flock management. For example, it can be used to assess weekly growth rates and evaluate feeding regimes. Or understand precise weights for individual animals to eliminate the risk of incurring financial penalties as a result of supplying under- or overweight animals at the time of sale. Through regular weighing, farmers can also quickly identify any health issues or problems linked to weight loss and manage and improve feeding regimes – all of which makes it possible to improve the efficient and cost-effective use of farm resources. Knowing exact animal weights also facilitates the accurate administration and recording of medicines and vaccines, and helps to reduce the over-application of drugs and the rate of drug resistance.


Within any flock of sheep, there is a substantial variation in the characteristics that influence an animal’s production level. Using EID or RFID tags to identify each sheep allows farmers to understand these variations which provide opportunities to select or sort animals based on different criteria such as scanning results, breed, growth rate, and so on to make informed management decisions for the operation. Electronic ID allows farmers to measure the performance of individual animals and make decisions specific to each animal, reducing costs and labour, while at the same time maximizing returns. Using a sheep handler with an EID scanner, weigh scale & automatic drafting, farmers can easily allocate or sort stock into different groups for better stock management. This could include such things as the division into different groups by weight to allow priority feeding or the drafting out of ewes with multiple pregnancies.


Fixed EID Reader Panels

A fixed panel reader is a reader that is permanently installed allowing animals to be identified automatically as they pass by. Many dairy parlours will use them to identify cows as they walk into the parlour or in each feed stall. Once the identity of the animal is known, data such as volume of milk or weight can be collected, or animals can be individually fed. Fixed Panel readers come in many different shapes and sizes to suit a variety of locations and use and are capable of reading tags up to approximately 100cm.

EID Panel Reader for Cattle


Mobile Options: XRS2 AND SRS2 Stick Readers

Tru-Test EID reader delivers information about your livestock rapidly. View individual animal tag data and capture management information against the EIDs to help inform your animal health, mating, and culling decisions. All readers are FDX and HDX compatible with built-in memory and wireless Bluetooth connectivity. Casings are rugged, reliable, water, dust, and shockproof.


Maximize individual animal performance and back up critical health, mating, and culling decisions by using the XRS2 EID Stick Reader to view and capture animal information. Suitable for cattle, sheep, and deer, the SRS2 and XRS2 feature a large, highly readable screen and capturing important information from the yard. Bluetooth® wireless technology connects your reader to your Weigh Scale Indicator and means you can easily share information using your smartphone.



For more information on our weighing and EID range visit

We are proud partners with TruTest for over 35 years with a full repair and backup team here in O’Donovan Engineering ensuring you get the most out of your TruTest device. Quality Lasts