^ no self-respecting farmer will say a COW has balls.
A cow is the mature female of the bovine world, despite the usage so many of us casually defer to when referring to cattle.
noun, plural cows, ( Archaic ) kine.
1. the mature female of a bovine animal, especially of the genus Bos.
2. the female of various other large animals, as the elephant or whale.
3. Informal . a domestic bovine of either sex and any age.
JUST BECAUSE #3 informally recognizes that SO MANY people are ignorant of the proper use of the word does not make it correct or accurate.
Edit: It's kinda right up there with "Only bulls have horns".
Calf: baby male or female
Weaner: after weaning from cow up to about a year old
Yearling: up to about age 2
Heifer: young female not yet bred
Cow: female anytime after first calving (sometimes second calf if you use the term ...)
Steer: castrated male to be fattened up for the destination of your freezer OR
Ox: if you keep him around to pull stuff
Bull: mature male, purpose breeding
Cattle: collective term for the collective
There's more but ... that'll do.
Double Edit: Nico, if English isn't your mother tongue, my apologies and consider this a learning experience.