FAQ on EID: Electronic Identification for Dairy Calves

By Jessica Mitchell

For years, non-replacement dairy calves were straightbred, and their path was fairly predictable: "bob" or "formula-fed" veal. Today, that landscape looks very different. The US veal industry has steadily declined since the 1960s (Ufer, 2022), and with national beef cow numbers at record lows, more dairy calves are now being raised for beef (Jaborek et al., 2023). Beef-on-dairy crossbreeding has also become a significant trend, helping strengthen the beef supply while adding a valuable revenue stream for dairy producers (Jaborek et al., 2023). With more calves leaving dairy farms than ever before, proper identification and traceability are increasingly important to maintain market access and support disease surveillance.

What's new about the USDA's Animal Disease Traceability rule?

The USDA's Animal Disease Traceability rule is not "new news." Official identification has been required for all dairy calves moving interstate (across state lines) since 2013. However, what's new is the type of ear tag that is required. As of November 5, 2024, calves must have ear tags that are both visually and electronically readable to move from state to state (USDA-APHIS, 2025). This means that silver metal National Uniform Eartagging System (NUES) or "brite" tags (Figure 1) are no longer accepted as a form of official identification. Tags in place before the new rule went into effect are grandfathered in.

This requirement ensures that calves can quickly be traced in the event of a disease outbreak, protecting you, your farm, and the industry. Field exercises have shown that states can trace electronic identification (EID) tags very efficiently – often in less than 1 hour. When tracing non-EID tags, it takes a significant amount of time and effort to search through piles of paperwork, and failed traces may occur because of transcription errors. While EID tags enhance traceability, they do not include GPS or environmental data tracking. Think of it like a barcode for your calves: when the tag is scanned by an EID reader, the only information that the tag provides is the individual 15-digit number that is assigned to it.

What's the difference between EID and RFID?

Radio-frequency identification (RFID) might sound more familiar than EID. USDA chose to reference EID versus RFID to remain "technology-neutral" in case other electronically readable devices become available in the future. RFID tags are EID tags that are both visually and electronically readable.

Does this rule apply to beef-on-dairy crossbred calves?

Yes! The new rule revised the definition of dairy cattle to avoid possible confusion. Dairy cattle are defined as: "All cattle, regardless of age or sex or current use, that are of a breed(s) or offspring of a breed used to produce milk or other dairy products for human consumption, including, but not limited to, Ayrshire, Brown Swiss, Holstein, Jersey, Guernsey, Milking Shorthorn, and Red and Whites" (USDA-APHIS, 2025). This means straightbred dairy and beef-on-dairy crossbred calves of any age or sex must have official identification to be transported across state lines.

What information needs to be on an official EID ear tag?

For all calves born in the US, the new rule emphasizes the use of 840-series EID tags, which are designed for one-time use and imprinted with a 15-digit animal identification number. EID tags come in different styles, including buttons (Figure 2) or buttons with panel tags.

Official EID tags are imprinted with:

• A unique animal identification number, which is a 15-digit number starting with 840 003
• US shield symbol
• The words "Unlawful to Remove"
• Manufacturer's logo or trademark (printed or impression of)

Note – There are also 900-series tags that begin with a manufacturer code such as 982, 985, 999, etc. These tags are not considered official identification because they do not include a nationally unique number for each individual animal.