All cattle born after 1 July 2000 
- Must be identified with an all numeric eartag in each ear
- Numeric tags were introduced on 1 January 2000 but made compulsory on 1 July 2000
All Cattle born after 1 January 1998
- Must have an approved eartag in each ear (double tagging)
- Each eartag must have the same unique number
- Animals will be identified by this unique number throughout their lifetime
All cattle born or imported into Great Britain before 1 January 1998
- May continue to be identified by a single tag bearing the same number
- May be identified by a single tag bearing a new number (in this case records must be amended and all documentation returned to BCMS for amendment)
- May be identified by a new set of double tags (in this case records must be amended and all documentation returned to BCMS for amendment, and subsequent replacements must bear the same number.