This is just like that Chicken or Egg? question that is floating somewheres on WikiAnswers. The obvious answer has to be the calf, since bos Taurus can't have come about without first starting as a calf and going from there.
Cow. Calf came after.
It's the name for a heifer that has had her first calf and is currently raising her first calf. It's also a name for a heifer that came from a heifer or cow that was that heifer or cow's first calf.
A cow is a female bovine who has had a calf. She was a calf when she was born, became no longer a calf after she was weaned. Before being put to the bull for the first time she was a heifer and became a cow after she had her first calf.
A cow is a mature female bovine that has had a calf. She was a heifer before she had her first or second calf.
Right after it had its first calf
Most often a calf's mother is referred to as the dam of the calf, or more commonly, a cow. If it's a heifer that has had a calf for the first time, some folks like to call her a first-calf heifer.
A young cow, in the sense of it being female, is called a heifer. Heifers remain so until they have had a calf. However in the more general sense, a young "cow" is called a calf.
The name of a baby cow is a Calf
The baby is called a calf and mother is a cow. Together they are called a cow-calf pair, or "mom and baby."
A young/juvenile cow is called a calf
Calf's liver comes from a baby cow.
A newborn calf, a baby calf or just a calf.