27 February 1998

Reading system options offered

Electronic identification will

feature strongly at the

Beef Event, in spite of

MAFFs decision not to go

down the electronic tag

route at present.

Peter Grimshaw reports

DATA can be written on to special ear tags, implants or rumen boluses. The same general principles apply to all three.

As with most emergent electronic systems, identification development has followed more than one pathway. There are currently two competing options, half duplex (HDX) and full duplex (FDXB).

Protagonists of each hope to gain MAFF and EU approval, because the lions share of a potentially lucrative marketplace will go to whichever gets official blessing. The key to the ambitions of E-ID developers is largely held by three-year EU trials being co-ordinated under the so-called IDEA project.

Both full duplex (FDX) and half duplex (HDX) offer advantages and disadvantages for reading. It is claimed that the initiation and response signals, which are transmitted in sequence, are more powerful using the HDX system, giving better signal clarity and allowing readers to work at a greater distance. This is the pathway being followed by electronics company Texas Instruments.

The company has been offering an electronic button tag for insertion in the ear since 1991. It is distributed by Oxley Systems for Allflex. The companys white button to button ear tag, containing E-ID, has been approved by MAFF for official visual identification as a secondary tag.

John Bailey, of Oxley Systems, says that the company has already supplied more than 180,000 E-ID tags to 550 UK farms. Among organisations using the system are Scottish Borders Traceability and Assurance Group, Carlisle Auction Mart, Dawn Cardington Abattoir in Bedfordshire and the British Limousin Cattle Society (BLCS).

Single button-type tags cost £3.50 each. A complete set, including distance-readable large or medium leaf tags to meet double tagging requirements, costs £4.10. Both sets of tags bear the MAFF crown, herd number and individual animal number on both sides.

The BLCS has been conducting electronic tagging trials since Jan 1995, and claims that losses have been minimal, averaging one a herd in the trial over two years.

The claimed advantage of the alternative system, full duplex (FDXB), is that it should be less subject to background interference than the HDX system, although Oxley Systems say the latter has a more powerful return signal to compensate for interference.

Technicians who favour the FDXB system claim, however, that it suffers less from local interference from electrical or radio equipment.

The FDXB transponder re-quires significantly less silicon chip surface, and is potentially smaller and cheaper.

Because there are two basic systems, the relevant ISO standard requires readers to be able to activate and record data from both. Universal readers are available, but it seems likely that the industry will eventually settle for one system to avoid the need for dual readers. At present, however, neither the EU nor member governments are committed to a particular system.

Readers so far available vary in complexity from a simple, pocket-sized, hand-held device which reads the UK and herd numbers from about 30cm (12in), to more complex readers that are hooked into the farm computer to provide full details of the animal and its management. Readers can also be fixed to crushes or feeding points to fully automate identification by transmitting data back to the farm, market or abattoir computer.

Concerns about accidental erasure of data on the tag, for example by passing under power lines, can now be discounted, the experts claim. However, as with any system, it is virtually impossible to protect electronic identification from determined fraudsters. Probably the most secure will be those that are carried internally, such as implants and boluses.

While a bolus that sits in the rumen offers most security from tampering, it is also relatively expensive. It is unsuitable for statutory identification, because it cannot be inserted at birth. It is also relatively large and easy to recover from the slaughtered animal. Losses during the animals lifetime are claimed to be lower than those with ear tags or implants.

Once recognised for statutory purposes, if an electronic tag, implant or bolus is lost, the replacement must be re-registered with MAFF, like any other tag. &#42

Richard Webber, of Shearwell Data, with electronic ID equipment capable of reading from both electronic systems.


&#8226 International Standards (ISO 11784 and ISO 11785) apply.

&#8226 64 bits of information.

&#8226 Speed of read 1.3m/sec.

&#8226 Frequency 134.2kHz.