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Cattle Ear Tags: From Metal Clips to Electronic ID Numbers

A small tag in the ear carries the number that links an animal to its vaccinations, weights and movements.

What Is a Cattle Ear Tag?

A cattle ear tag is a small plastic or metal tag fixed through the ear with an applicator. It carries an identification number so that each animal can be recognized individually. Tags are now one of the most common ways to identify cattle, alongside hide brands, and they carry something a brand cannot: a number that can be matched to a database.

This page draws mainly on a Merck Animal Health guide to electronic identification, a company source that describes ALLFLEX products. Its claims are treated here as the manufacturer's account.

Visual Tags and Electronic Tags

Visual tags show a number that a person can read by eye. They are often sold in matched sets, where the visual tag, an electronic tag and a tissue sampling unit share one unique ID.

Electronic identification tags, called EID tags, are passive RFID tags. Each has a unique 15-digit number and is designed to last the lifetime of the animal. The tag has no battery. A copper wire antenna transmits the number to a reader.

What the Number Means

The first three digits of an EID number identify the country, which is 840 for the United States, or the manufacturer, which is 982 for ALLFLEX. USDA 840 tags use the U.S. country code and require a premises identification number from state ID coordinators. Manufacturer-coded tags need no premises number.

USDA 840 tags replaced older orange metal brucellosis vaccination tags and silver brite clips used for interstate movement of breeding animals. The guide notes that ALLFLEX introduced RFID tags to the livestock industry more than 30 years ago but gives no other specific dates.

The Key to Why Ear Tags Spread

Ear tags caught on because they turned an identity into a record. The documented uses are:

  • They link an ID to vaccinations, deworming, weight gain and breeding dates, capturing data in real time and reducing manual errors.
  • They connect to management software and scales, so data moves with the animal through production phases.
  • They give cow-calf producers treatment histories that make calves more appealing to buyers.
  • They help state and federal veterinarians track disease through unique IDs.
  • They replaced older systems like brucellosis tags and brite clips with a single standard.
  • Their limit is that readers are optional and tags only help when records are kept.

Applying Tags Correctly

The guide stresses that the tag and applicator must come from the same company. A universal applicator works with all species tags within that brand. The Alberta government publishes best practices for RFID ear tag application, which is a useful companion for producers.

A tag that fails or falls out breaks the link between an animal and its records, so careful application is part of the system.

Ear Tags and National Traceability

Ear tags are the front line of national systems. Australia's National Livestock Identification System records cattle movements from the property of birth through to slaughter, and the animal's approved identification device is how those movements are matched to the animal. The system is described in the NLIS approved technology fundamentals.

The Merck guide does not describe a federal U.S. mandate requiring EID tags for cattle, so this page makes no claim about current U.S. rules. Producers should check with their state veterinarian.

Learn More

For companion reading, see the livestock branding page, which covers the older permanent mark. For more on working cattle, visit the ranching section of farm.FM or read a farm.FM story about herd health records.

Timeline

  1. 1900sEar tags and clips begin to be used to identify cattle, per the hall's records.
  2. Before 840 tagsOrange metal brucellosis tags and silver brite clips are used for interstate movement of breeding animals.
  3. About 30 years agoALLFLEX introduces RFID tags to the livestock industry, according to its own guide.
  4. Before 840 tagsVisual tags and clips mark animals for brucellosis control and interstate movement.
  5. TodayUSDA 840 electronic tags carry a unique 15-digit number linked to a premises ID.
  6. OngoingMatched sets pair a visual tag, an EID tag and a tissue sampling unit under one ID.

Frequently asked questions

What is an EID ear tag?

An EID tag is a passive RFID ear tag with a unique 15-digit number. It has no battery and a copper wire antenna transmits the number to a reader.

What does 840 mean on a cattle ear tag?

The first three digits identify the country or manufacturer. 840 is the United States country code and requires a premises identification number. ALLFLEX uses the prefix 982.

What can producers do with ear tag data?

They can link an ID to vaccinations, deworming, weight gain and breeding dates, feed it to management software and scales, and support disease tracing by veterinarians.

What did USDA 840 tags replace?

They replaced orange metal brucellosis vaccination tags and silver brite clips used for interstate movement of breeding animals.

Sources and further reading

Profiles are compiled from public sources and reviewed against them. See our editorial policy to suggest a correction.

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