This section is from the book "The Wonder Book Of Knowledge", by Henry Chase. Also available from Amazon: Wonder Book of Knowledge.
The question of how to mark animals started with the first stock raisers. In those days the main object was to provide some way animals could be identified as to ownerships, and many crude and more or less cruel methods were used, such as notching or lopping off part of the ear or branding with a hot iron, burning a letter or figure often ten or twelve inches high on the side of an animal. Branding in this way was used mostly by cattle raisers when large herds were grazed on the western plains. The large brand made it possible for cowboys on horseback to separate the cattle of different owners, as the brand could be seen at some distance.
Courtesy of Wilcox & Harvey Mfg. Co. BRANDS FOR IDENTIFICATION.
As the industry advanced the methods of marking improved. At the present time a mark in the ear made of metal is most commonly used. These are in many different styles such as narrow bands looped into the edge or in the form of a button fastened through the ear.
Tags are lettered with owner's name and address and numbered, which serves not only as a mark for identification of ownership but as a means of keeping a record of each animal by number; also in making health tests before shipping from one point to another.
 
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