Steers going to market don't need to waste energy and lose fat by being distracted by natural urges to reproduce.
"Male cows" castrated before reaching sexual maturity are called steers.
A wether.
A male horse castrated before reaching sexual maturity is called a gelding. A male horse that is sexually mature is called a stallion.
A one-testicled bull is still called a bull. When he is castrated after reaching sexual maturity, he is called a stag.
Male wallabies usually obtain sexual maturity at 2 years of age. Females, however, obtain sexual maturity a few months before that.
The main change is physical growth. There is also sexual growth as in reaching sexual maturity.
B. Spraying!
Geldings have already been gelded: They are castrated male horses, which means their testes have already been removed. To "geld" is to castrate a male horse like a stallion or colt. Thus, geldings do not need to be castrated because they have already had the surgery done on them earlier in their lives. Horses (more specifically stallions or colts) can be gelded at any age but most are gelded when they are around yearlings or two-year olds, usually right after their testicles drop, or before they reach sexual maturity. However it's not uncommon to have stallions gelded after reaching sexual maturity, especially if they are no longer needed for breeding purposes, or even to calm the horse down, since stallions are more difficult to handle due to hormones than mares or geldings.
The vast majority of eggs are eaten before hatched and the vast majority of hatchlings (fry) are eaten befaore reaching sexual maturity.
Yes! A kitten that has been neutered before reaching sexual maturity (often around six months old) and begun spraying, prevents the kitten from developing the need to spray at all.
After metamorphosis, salamanders reach sexual maturity at one year.
It is still called a wether but if it is older than six months of age, in some countries, the castration can only be performed by a veterinarian and under anaesthetic.