Dry ice is an innovative way to mark livestock ownership. Instead of hurting and scarring the cattle, freeze-branding causes the hair follicles to produce white hair. This creates a highly visible brand without a scar.
A freeze-branding iron is made from copper with the face (characters) slightly rounded. The cow is herded into a "squeeze chute" where a small area of hair is trimmed very close to the skin and sprayed with alcohol. The branding iron is then pressed onto that small area for about a minute. The freezing alters the hair follicles, resulting in the hair growing out white. The animal feels the cold only briefly because the area is quickly numbed. The branding iron is chilled by immersing it in a mixture of dry ice and 90% alcohol for a few moments until the mixture quits bubbling, indicating that the iron is ready. This is a less cruel and more humane way of branding cattle compared to the traditional hot branding iron.
Branding Iron Photos from L-H Branding Irons