The British Cattle Movement Service (BCMS) is the organisation responsible for maintaining a database of all bovine animals in the United Kingdom, except for Northern Ireland, which has a separate database maintained by the Department of Agriculture and Rural Development. It was established in the wake of the Bovine spongiform encephalopathy crisis in the UK, and is part of the Rural Payments Agency. Other member states of the European Union have similar cattle tracing systems.
Every bovine animal in the United Kingdom (as elsewhere in the European Union) has a unique number, shown both on an ear tag in each ear and on a paper cattle passport which is held by the current keeper of the animal (the system covers both cattle and other bovine animals such as water buffalo and bison). The number and passport remain with the animal throughout its life, and is recorded by the slaughterhouse at its death, allowing traceability of the beef. The BCMS central database is called the Cattle Tracing System, and works alongside the physical passport to record the births, deaths and movements of all cattle.
Cattle Tracing System 
The Cattle Tracing System (CTS) is the database for all cattle in Great Britain (Northern Ireland has a separate tracing system), to which farmers must notify births, movements and deaths of cattle on their holding. The system was introduced on 28 September 1998 in order to meet EU legislation requiring all member states to have a computerised tracing system by the end of 1999. There are currently four ways to notify CTS about births/movements/deaths including via the postal service using movement cards (cheque-book style passports only) and passport applications, over the telephone using the CTS Self-Service Line, over the internet using the CTS Online service or through third party software using CTS Web Services.
Cattle passport 
The cattle passport has taken three forms.
- From its introduction on 1 July 1996 the passport was a single green A4 paper sheet. This showed details of the animal including its birth-holding details, ear tag number, breed, date of birth, sex and its mother's ear tag number. Also included were a number of sections to be filled in when the animal moved to other holdings, showing the movement date and the new holding number (holdings include other farms, agricultural shows and abattoirs). At the time of its introduction there was no requirement for such movements to be registered centrally. When this requirement was introduced on 28 September 1998, a further A4 document was issued for all existing cattle, to be used in conjuction with the green A4 passport. This was the Certificate of CTS Registration, and it included pre-paid postage tear-off movement cards to be sent to BCMS to register each movement. Movements could be registered using these cards, or electronically by using the new online CTS. Because of the relatively short lifespan of cattle, few green A4 passports remain in use.
- From 28 September 1998 to 2011 the passport was issued as a booklet, made in a similar style to a cheque book. This included the same information as before, but with spaces for bar-coded stickers for holding numbers, and many pages to allow for numerous movements. The prepaid cards were incorporated in the booklet as tear-out pages, so animals with this format of passport did not also need a Certificate of CTS Registration.
- From 1 August 2011 the format returned to a single A4 page. The tear-out cards were omitted, requiring all movements relating to that animal to be reported electronically or by telephone.
Each change only affected new issues of passports, leaving the old passports in circulation and maintaining former reporting methods for them. Replacement passports (for example in case of loss or amendment) are in the format which is current at the time of re-issue.
When an animal dies, the date of death is entered in the passport and this is returned to BCMS. The death may also be notified electronically.
If the rules for animal registration (and thus animal traceability) are not followed correctly, a passport will not be issued (this is most commonly where the deadline for calf registration is missed, of 28 days from birth). Instead the animal will receive an A4 Notice of Registration document (similar to the Certificate of CTS Registration), and its details will be held on the CTS. Such an animal may be used for breeding, but it may not enter the human food chain and it may not normally move between holdings except to slaughter.
Ear tag number 
Every bovine animal in the EU must have an ear tag in each ear: a primary tag, which must be a large yellow plastic tag, and a secondary tag, which may be similar to the primary, or it may be a smaller yellow plastic tag or a metal clip. Each tag must have the cattle passport number printed or stamped upon it, and it may also have a RFID chip bearing the same number in electronic form.
The British ear tag and passport number is in the format UK HHHHHH CNNNNN – this has been in use since 2002, before which other formats were used. The current format breaks down as follows:
- UK (or another EU country abbreviation) – the country code (electronic readers read the UK country code as 826, in line with ISO 3166);
- H – a unique six-figure number given to each herd (usually one herd per farm, or sometimes one for each cattle enterprise on a farm);
- C – a check digit (cycling from 1 to 7; the check digit for the first calf varies from herd to herd);
- N – a sequential five-figure number for each calf born into that herd (with leading zeros where necessary).
Numbering example: If a herd had the number 123456, its first three calves might have the numbers:
- UK 123456 600001
- UK 123456 700002
- UK 123456 100003
The check digit highlights most errors in reading or recording the sequential number. A single-figure error in the sequential number will not match the check digit, unless it happens to produce a figure differing by a multiple of seven (for example, "600016" would have to be misread as "600086", or "500010" as "500080"). Double errors in both the sequential number and the check digit are also unlikely to produce genuine animal numbers. An error in the herd number might generate the herd number for another herd, and thus the number of an animal in that herd. However, the check digit for the first calf varies between herds, so only if the other herd happened to share the same check digit for the first calf would a whole apparently genuine animal number be produced.
Similar numbering is used for sheep and goats, with the omission of the check digit (and there is no individual paper passport). The number assigned to a sheep and goat flock is usually (but not always) the same six-figure number as that assigned to a cattle herd on the same farm.
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