Old Brass Double-sided "47" Livestock Ear Tag

This would most likely once have flagged the ear of a cow or bull as an identifier. Certainly there are many of these around, but it's the wide and irregular shape of this one, and the weight of the brass, and the hand-written quality of the impressed numbers, especially, that does it for me. Plus, strung on a chain as a pendant, it would seem a very good present for a dear one turning 47--or for someone long past 47, forever young!

 1 7/8" w x 2 1/8" t, double sided, excellent condition, early 20th c. I would guess.