When a keeper reaches the maximum animal number issued for cattle of their holding, for example 99999, a new herd number will then be allocated, and the number will restart at 70000.
Pan fydd ceidwad yn cyrraedd y tag â'r rhif uchaf ar gyfer gwartheg eu daliad, er enghraifft 99999, caiff rif buches newydd, a bydd y rhif yn ailgychwyn ar 70000.