Freeze Branding, also known as CryoBranding is a method of branding with extremely cold irons. Freeze Branding destroys the natural pigments in hair, thus producing the growth of white hair. This relatively painless method of branding reduces hide damage. The brand raises a welt on the animal as soon as the hide thaws and can be read immediately after branding. It usually is readable until the white hair appears. This may take 20 days to several months. It is a successful permanent ID for bulls and heifers and can be done when doing fertility exams (semen testing or pelvic measuring).