Frequently asked questions

Year/Letter

2025 - N

2026 - P

2027 - R

2028 - S

Ear tags are a great way to easily identify an animal out in the field, but they tend to fade after several years or get lost, so should be considered only part of your animal identification system.

For permanent identification ear tattooing, hot-iron and freeze branding are acceptable, as well as USDA 840 tags (last six digits) and veterinarian applied brucellosis tags.

The tattoo of an animal should include a series of letters and numbers.

The first letter of the tattoo corresponds to the first letter of the breeder/owner’s herd prefix of the farm or ranch on which the animal was born. The middle digit should be unique to the breeder/owner’s farm or ranch where the animal was born (order of birth is preferred) and the last digit should be the year designation of PDCA.

For example: High Horse is the prefix of breeder or the owner at the time of calving, first letter is “H”.

The calf is the third born in the year 2025, the second digit is “3”.

The PDCA Year code for 2025 is L so the last digit is “N”.

This results in a tattoo of H3L in either the right or left ear.

Lethal genes exist in every breed of cattle:

Neurophathic Hydrocephalus and Arthrogryposis Multiplex are lethal genetic defect that affects Angus and Angus-influenced cattle, Tibial Hemimelia is found in Shorthorns and Maine-Anjous. Beta (ß)-Mannosidosis in Salers, Contracture in Holstiens, Hypotrichosis congenita (Hairless) in Holsteins, Fresians and Jerseys and the list goes on. Chondro and PHA are the two biggies in the Dexter breed.

Lethal genes typically cause birth defects which results in the death of the fetus or newborn calf but in some cases the resulting deformaties can mean death for the dam as well.

But nowadays a lethal outcome is entirely preventable by using genetic testing to identify a carrier, having a clear understanding of inheritability and using both to make wise breed pairings.

Learn more

There are three commonly used laboratories for genetic testing for cattle.

UC Davis is the most commonly used laboratory by PDCA members and has a solid reputation for its accuracy.

UCDavis

Neogen/Igenity

Texas A&M University

The mapping of genetic markers within an animal's DNA to establish a unique identification like a fingerprint.

Genetic material (DNA) is obtained from hair folical samples.

When you have the genotype test performed at UC Davis, be sure to click the PDCA as your affiliate organization to receive the discount. With our affiliate discount the test is only $30.

Cattle DNA tests are carried out using 20-30 hairs with roots, easily pulled from the switch (tip) of the tail then sent to a genetics laboratory for analysis.

Detailed Instructions from UCDavis Veterinary Genetics Laboratory