How to tell a cow''s age by her teeth

"One of the ingredients used in selecting which cows to cull is the age of the animal,” said Dave Sparks, Oklahoma Cooperative Extension Service veterinarian and food-animal quality and health specialist. Evaluating her teeth can help you age the animal.

Determining the age of cows up to 5 years of age is simple and accurate: the animal has two permanent incisors at 2 years of age, four at 3 years of age, six at 4 years of age and a full mouth of eight permanent incisors at 5 years of age.

"Determination is not as accurate after 5 years of age, but close enough for practical purposes since producers don't really care about a cow's age as much as how efficiently the animal can graze,” Sparks said.

As a cow ages, her teeth wear down to be less blade-shaped and more triangular, and spaces start to appear between the teeth.

At 5 years to 6 years of age, the permanent incisors are leveled, both pair of intermediates are partially leveled and the corner incisors show wear. Incisors show noticeable wear at 7 years to 8 years of age, while the middle pairs show noticeable wear at 8 years to 9 years of age. The corner teeth show noticeable wear by the time a cow reaches 10 years of age.

"After the animal passes 6 years of age, its arch gradually loses its rounded contour and becomes nearly straight by the 12th year of life,” Sparks said. "In the meantime, the teeth gradually become triangular in shape, distinctly separated and show progressive wearing to stubs, all becoming more marked with advancing age.”

Sparks said cattle producers cannot afford to keep marginally productive cows when they can be replaced by more profitable females, not in today's competitive beef industry.

Click here for more from Sparks on aging cows.