Ear Tag Placement

Ear Tag Placement
Cattle feeders in southwestern Kansas whose cattle died due to heat stress have resources available to help them recover from those losses. (Photo: K-State Research and Extension, Flickr/Creative Commons)
December 4th, 2022 | Dr. Ken McMillan


I am really confused about 840 ear tags. Is there a difference between 840 and 840 RFID tags? Are there rules on placement of 840 EID button ear tags? Are these tags considered official identification for proof of brucellosis vaccination?


When we talk about 840 tags, we are referring to the new standard for animal identification and the effort to improve animal traceability. The number “840” is code for the United States. After the 840, these tags will have 12 other numbers unique to that animal.

The term “RFID” refers to radio-frequency identification, telling us that those are tags that can be read with a special scanner. These scanners are becoming more common because they make it easier and more efficient to manage, track and identify our animals. An RFID tag can be an all-in-one tag with an 840 number, where the RFID component allows for scanning to show the number printed on the tag.

The 840 tag doesn’t have to be an electronic RFID tag. The 840 can simply be a visual, or bangle, ear tag. These are official identification for cattle in all states. They look like traditional ear tags, but they are imprinted with that unique number, which is linked to the animal and the premise (farm or ranch).

These visual tags can be paired with separate RFID button tags. So, producers can apply visual tags with whatever identifying numbers they choose or that are already in the ear, and then link that number back to the official 840 number.

The new official brucellosis identification is an orange RFID button. These are placed in the right ear by the herd veterinarian at the time of vaccination. An official tattoo is placed in the right ear between the middle two cartilage ribs. This tattoo begins with “R” for reduced dose and is followed by the official USDA shield with a “V” in the center, and the last number of the year the calf was vaccinated. USDA prefers producers apply ear tags in the left ear, leaving the right ear for official use.

All ear tags should be placed two-thirds of the way from the outside edge of the ear, and one-third of the way from the head between the middle two cartilage ribs.

If a visual tag and an EID button are placed in the ear, the EID button should be placed in this location with the visual tag a little closer to the outside of the ear. The female (thicker) portion of the tag should always be to the inside of the ear. The male portion (the part that fits over the pin) should always be to the outside. Placement of the button deep in the ear is not recommended.

Go to the USDA Animal and Plant Health Inspection Service page on “Brucellosis” for more information on proper identification: www.aphis.usda.gov/aphis/ourfocus/animalhealth/nvap/NVAP-Reference-Guide/Control-and-Eradication/Brucellosis.



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