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What do Ear Tags on Cows Mean?

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We've all seen them--you know, those colored things in a cow's ear? Why is that there? Is it supposed to mean something to somebody? That ear tag is marked using a special code and helps the producer keep a record of each animal.

Ear Tag Function

Ear tags are used by the livestock producer to keep production records of bloodlines, birth dates, vaccinations and other key criteria necessary for raising animals as a career. Without some form of identification, it would be impossible to manage the records of each animal, especially when entire herds are raised by one person or family.

Numbering System

Each producer uses his own numbering system. One method is to number the year of birth using a letter from the alphabet. For example, calves born in 2009 would be given the letter "A." Calves born in 2010 would be given the letter "B," and so on. When the letter "Z" is reached, the producer would begin again with "A" the following year.

Because the identifying letters need to be clearly seen from a distance, some letters are not used, such as "O" and "Q". These two letters could easily be misidentified.

Numbers are sometimes also used. They indicate the litter or lot in which that animal was born. For example, using our example above, if an ear tag read "A01", that combination of letters could mean that animal was born in the first litter of 2009.

Factors to Consider

Each producer develops his own method of identification. Once an animal is given an identifier, that combination of letters and numbers stays with it throughout its lifetime. The most important consideration for animal identification is that the tag is permanently attached. If it falls off, the producer has no way of being sure of that particular animal's history.

Other Methods of Identification

Just as each producer determines his preferred numbering system for keeping a record of each animal, he also has preferences for the type of identification used. While some producers prefer ear tags, others might use ear notching, branding, nose printing, tattoos, neck chains or microchips. Part of the producer's decision is based on the ease of use and cost of equipment necessary.

It's Not Only Cattle

Cattle are not the only animals identified by tags or other methods. Any herd or flock of animals raised for profit is marked similarly. Pigs, chickens, sheep, goats and rabbits are a few examples. Animals are also tagged for research purposes, such as flocks of geese to determine migration patterns, and endangered species to prevent extinction.


Since 2001, Melanie Raine has written articles for the "Worthington Daily Globe," "Tri-County News," "Lakefield Standard," Heron Lake Watershed District, North Heron Lake Game Producers Association, and the "Journal of Soil and Water Conservation." She also helped organizations receive more than $3.6 million in grant funds, and in August 2009 began a freelance career as a ghost writer.

Photo Credits

Robert Postma / Design Pics/Design Pics/GettyImages