Determining Cattle Age for BSE

David Nistler, Duval County Cooperative Extension Service 

As most of you know, on January 12, 2004, the U. S. Department of Agriculture (USDA) issued new rules to protect the public from Bovine Spongiform Encephalopathy (BSE). Among the new rules, specified risk materials (SRM’s) in cattle more than 30 months of age are not allowed into the human food supply. 

Currently, most of the requirements for removing SRM’s are focused on the relationship between the age of cattle and onset of the disease, which has been around 30 months of age for other countries. There is some debate, if 30 months is the appropriate age in the U.S., based on the practices that were previously implemented to reduce the risk of BSE, but at this time 30 months is a regulatory requirement. 


USDA’s Food Safety and Inspection Service (FSIS) has determined that documentation (birth certificate, animal passport or animal identification systems that include the age of the animal), rather than dentition (kind, number and arrangement of teeth) can be the primary means of determining the age of cattle at harvest. Because many of the cattle processed in the U.S. do not have this information, dentition was included in the interim rule as an alternative for age determination. FSIS maintains that documentation is the best option because dentition provides a means of making only general determinations about age.  

FSIS Notice 10-04 released January 29 highlights some of the documentation requirements. (See also:

The characteristics of documentation that is most useful in determining the age of cattle offered at harvest are:

Documentation (e.g. records of certificates) that can be related to individual cattle and not just information about an entire lot; and

Documentation that provides evidence of age that goes back to the farm where the cattle were born, including that name and address of the owner.

 FSIS says examples of farm or ranch documentation may include:

Pregnancy check records (checks for individual cows and the results of the check for each one);

Records of which cows were in a herd when a bull was put in with the herd, and when the bull was removed from the herd (to determine start of gestation);

Records that document when individual cows were artificially inseminated;

Calving records that document where (i.e., name and address of the producer) and when a calf was born; or

Identification applied to calves (e.g., records from branding, electronic ear IDs, or ear tags).

Dentition 101

Cattle have 38 teeth, 8 of which are incisors. The incisors, which are situated near the nasal region of the mouth, are found in the lower jaw. The other teeth are the premolars and molars, also known as cheek teeth, are found in both the back upper and lower jaw.

When determining age, FSIS rule inspectors will look for signs of age in the incisors. Incisors erupt at different months of age. Eruption is the emergence, penetration or piercing of the tooth or teeth through the gum line.

 Incisors are ordered in pairs, from No. 1 through No. 4. During an examination, the inspector looks at the animals’ mouth to see if at least one of the second set of permanent incisors (No.3) has erupted to determine if the animal is more than 30 months of age. Eruption of the third permanent incisor is the FSIS standard indicating that an animal is 30 months of age or older. Relying on the eruption of the third permanent incisor as the standard to verify cattle are 30 months of age may cause some cattle 24 through 29 months of age to be identified as 30 month of age. 

For more information concerning dentition go to: or

Source: Interim Guidance For Non-Ambulatory Disabled Cattle and Age Determination

Questions and Answers, Regarding the Age Determination of Cattle and Sanitation (51KB PDF)