Currently green fluorescent ink appears to work best. Calves can be tattooed at any age, preferably at birth, with the same tattoo number in each ear. Summary To keep valuable information on each calf meaningful and accurate, identify the calves as soon after birth as possible. Eartagging is quick and easy. Later sketch, photo, brand, or tattoo them.
Tattoos are the method of choice for solid-colored animals.
For broken-colored animals being registered, sketching or photos are required. For nonregistered animals, freeze branding is very useful, as are the other methods. Good management begins with knowing as much as you can about your animals. Dairyman's DHI Manual. Dairy Records Processing Center at Raleigh.