British Cattle Movement Service - Ear Tag Number

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.