A cow can live anywhere from 2 years to almost 20 years. How long a cow lives depends on her genetics, her health, her general productivity (regardless if she's a beef or dairy cow), and other attributes.
A cow will have generally given birth to her first calf when she was two years old. Some producers like to push that age to a little bit older, such as when she's two-and-a-half to three years old. Generally though, in most conventional cattle production systems, two years of age is the target age for when a female bovine first calves.
Note at this point that prior to calving, a cow has been called a heifer. A heifer becomes a cow after she's had her first calf. Some producers though, like to call such new-come cows "first-calf heifers."
A first-calf heifer has the potential to be culled after her first calf for several reasons, ranging from poor mothering ability to health issues. It's not entirely uncommon to cull cows at this age.
From there then, if that first-calf heifer proves herself to be a good productive member of the herd, a cow will be expected to birth a calf annually; once every 12 months. Therefore, a cow can birth anywhere from 1 to 18 calves (or more) in her lifetime.
The Bovine Practicum Q&A "blog" is an informative, just-for-fun section where I find a variety of questions that are often (and not-so-often) asked by inquisitive people like you, and answer them to the best of my ability. Much of the questions have come from a wide variety of reaches from the Internet.
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