It's interesting that the more important the animal is for humans, the more words there are for it in relation to age and sex. (This probably gets filed in the same place as the standard observation that "the Eskimo have 200 words for snow." They don't really; they only have about 30, but the idea is the same.)
Wild animals of importance usually have terms for the species in general, males, females (sometimes the same as the species name), and the young:
Deer = Buck (or "Stag" for a sexually mature, dominant buck) -- Deer (or the old-fashioned "Hind") โ- Fawn
Wild boar = Boar -- Sow -- Piglet (or, frequently in this area, just "Pig.") [This one's unusual in that the species is more commonly known by the MALE name, though they are also called "wild pig" by some people around here.]
Some terms get used across species, such as "Sow" for female bear as well as pigs, both domestic and wild, or "Queen" for sexually mature female ants, termites, and cats. "Tom" also works for both the male turkey and cat.
For domesticated animals, there's an additional term for the castrated male (if they are used for any purpose). For example, rabbits and ducks, while long domesticated are not normally castrated, hence no common term for the state. Dogs are castrated frequently enough and have been long enough that there OUGHT to be a term for them in English, but I can't think of one.
Human = Eunuch; Castrato; occasionally Gelding
Horse = Gelding
[Horses and humans also have separate terms for the young of both sexes - boy-girl : colt-filly - showing their cultural importance. The term "Entire" is sometimes used around here in place of "Stallion" to make even more specific that a male horse of any age has NOT been castrated; "Stallion" being reserved for a more mature male used specifically for breeding purposes.]
Cattle = Steer (when young or intended for meat); Ox (when older or intended as a work animal); occasionally Bullock. [The economic importance of the castrated male can be seen by the proliferation of terms.]
Rooster = Capon
Sheep or goat = Wether
Swine = Barrow (castrated before sexual maturity); Stag (castrated after sexual maturity)
As an interesting aside in Esperanto, the International Language, the problem of castrated anything is easy. You learn one word, chavalo, for example means "horse." "virchavalo" means male horse or "stallion," chavalino means "mare" or female horse. "chavalido" means the young horse, chavalaro is a group or horses or a "herd." "chavalajo" means a "horse place" or stable.
Then "eksvirchavalo" is the castrated horse or gelding.
This applies to any animal. Well, almost. A man is a viro and a woman a virino and you might expect a eunuch to be an eksviro, but he is actually a "eaunuko."
In a sense, bullock, steer and ox are all the same thing. However, a bullock is specifically a young animal. A steer is older and is intended for beef, whereas Oxen are kept as draught animals.
A modern misconception is that people imagine that Horses were always the primary draught animals, but this only happened during the 18th century. Before that almost all ploughing and pulling of carts was done by Oxen. Horses were kept mainly for war and were much too valuable.
cob (1) a big or notable man; a short legged horse; a male swan; a lump (esp. coal, ore or clay); a rounded object; a herring's head; a loaf of bread (cobloaf); the axis of a head of maize (corn cob); a cobnut; an irregularly shaped Spanish-American Dollar
cob (2) a kind of composition of clay and straw used for building