Method for providing ear tags for the ears of cattle by means of a welding device, wherein the ear tags comprise an ear tag part (2) and an attachment part (1), wherein the welding device (52) is provided with a first conveyor for transport of ear tag parts in a first transport direction, wherein the first conveyor is provided with ear tag part holders consecutive in the first transport direction and first passages extending through the first conveyor transverse to the first transport direction, and a first pressure pin having a first distal end surface and a second pressure pin having a second distal end surface that can be moved towards each other transverse to the first transport direction for forming a welded joint between the distal end surfaces by means of ultrasonic welding, wherein the first pressure pin is passed through a first passage.
