It is often used to describe the transition from being a heifer (a young female cow that hasn't given birth) to becoming a cow.
Here's a breakdown:
* Heifer: A young female cow that hasn't had a calf yet.
* Freshening: The act of giving birth for the first time.
* Cow: A female bovine that has given birth at least once.
So, when a heifer "freshens," she becomes a cow.