When tattooing your animal, your personal herd prefix goes in the right ear & the year tattoo prefix and number you assign goes in the left ear.
To determine the left or right ear stand behind the animal and look towards the back of the head.
USBGA TATTOO LETTERS
Note: The letter should correspond with the year the animal was born. (Ex. If the animal was the first born on your farm in 2015 then the left ear tattoo could be E01)