In Europe all bovines are registered in the National database. The identification in this database is done by an unique identification number, the number that corresponds to the numbers on the ear tags of the animal.
At present, the regulations in the Netherlands are that every calf has to be ear tagged and registered at I&R within three days after birth*
Last year the dairy organizations made a proposal to shorten that period to 24 days after birth, but this got rejected by the board of dairyfarmers. The negotiations on this matter are still going on.
* different rules apply for calves kept in nature reserves
The correct position to apply the ear tags is in the middle of the ear, in between the two lines of connective tissue. See picture:
Inflammation at the ear as a result of the ear tag it’s advisable to immediately clean and disinfect the infected area of the ear. In case of a heavy infection it’s better to remove the ear tag. Wait with the application of a new ear tag until the ear is fully recovered.
Inflammation at the ear caused by the ear tag