What part of "unmated" cattle are you referring to? Are you referring to females, or males or both? It's hard to tell what you're asking, but I'll do my best.
An "unmated" young female, or a young female bovine that has not been bred yet is a heifer. A bull that has never bred a cow or heifer before is often referred to as a virgin bull. A cow that has calved but hasn't been bred yet is referred to as an open or barren cow.
cattle - they don't differ in name simply because they are unmarked
Male rats are called bucks, unmated females are called does, pregnant or parent females are called dams, and infants are called kittens or pups
A cattle stall is called a crib.
A group of cattle is called a herd.
A number of cattle is called a herd of cattle. A number of pigs is called also called a herd.
It can be called a ranch or a cattle farm.
A Scottish cattle pen is called a byre.
Cattle are not called steers, rather steers are called cattle, when loosely referring to more than one steer or indiscriminate bovine. Steers are cattle because cattle are a collection of bovines that include steers, as well as cows, heifers, bulls and calves. However, cattle can be called steers if these cattle are specifically castrated male bovines, but cattle should not be called steers if they are not specifically and only castrated male bovines.
The cars were called "Cattle Cars". They were called cattle cars because that's what cattle were put into when they had to travel.
A group of cattle is called a herd.
Cattle that are ready for slaughter. They are also called finisher cattle or fats.
A group of cattle is called a herd.
Milk cattle are also called Dairy cattle or Dairy cows.