I come from a rural background.

Virgin female pig = gilt Later a sow.
Virgin female cattle = heifer Later a cow.
Virgin female horse/donkey/mule = filly Later a mare.
Virgin female cannabis = sinsemilla. Later to be used with Pink Floyd albums and Doritos.

Castraged male pig = barrow, never to a boar.
Castrated male cattle = steer, never to be a bull.
Castrated male horse/donkey/mule = gelding, never to be a stallion.
Castrated male human = eunuch never to be a father.

Inquiring minds want to know...