When I say “cow” or “bull”, chances are you have a specific animal in mind. But these terms refer to the female and male of several mammals (moose, elephants and whales, for example). Is there a generic name for the singular of the animal whose milk we buy in supermarkets?
“Cattle” is plural, by the way.
Cow? 
But, since you didn’t want cow, I’d go for bovine.
For those of you who’d like me to explain myself.[sub] you’ll forgive me for the two short posts above, won’t you?:o[/sub]
The mature females of these animals are called ‘cows’"
[li]Elephants[/li][li]Rhinoceroses[/li][li]Opals (Hi!)[sup]1[/sup][/li][li]Moose[/li][li]Seals[/li][li]Whales[/li][li]Cows (bovine)[/li]
I guess the only way you can tell between these (and any others) is through context. Usually, anyone would assume that a “cow” is of the bovine variety, but this would change if they happened to be watching a documentary on the habits of the Rhinoceros. In the case of a documentary about cows being attacked by female seals, the word ‘bovine[sup]2[/sup]’ could (but probably wouldn’t) be used.
[sub]1. This item is an attempt to figure out some of the weird traditions of the SDMB and does not imply in any way that the Opals mentioned are, or would be called, ‘cows’.
According to Merriam Webster’s, while the primary meaning of “cow” is “the mature female of cattle,” the second meaning given is “a domestic bovine animal regardless of sex or age.” So, one could properly call a bull a cow.
But this strikes me as not really correct, according to normal usage. Most people will assume “cow” refers only to adult females. And note that MW has to use the awkward construction “domestic bovine animal” in the second definition, implying that there is in fact no generic term for the single animal. This is in contrast to sheep/ewe/ram/lamb, horse/mare/stallion/colt, goat/ram/nanny/kid, hog/boar/sow/pig, etc. MW would have us believe the same sequence for cattle is cow/cow/bull/calf, which I don’t think most English speakers would feel is right.
IMO, there really is no proper generic term for the singular of domestic cattle.
I knew one farmer in New Zealand who used to refer to his animals in the singlar as “cattle beast.” I’m not sure how general this usage might be.
Producers of the animals to which you refer call them “cattle” and at times when the animals are especially reluctant to do what is expected of them %:*&%$#!! cattle. I have occasionally heard ranchers refer to them as “beeves” (as in the plural of beef) although it has been a number of years since I last heard this term used.
TV (former ag journalist)
Sorry, for goats the sequence should be goat/billy/nanny/kid.
Dammit, that’s goat/nanny/billy/kid.
I suppose you could wander about using the term milch cow, but you’d probably get some odd looks for confusing a name which has worked quite nicely for far longer than there has even been an English language.
Sometimes when languages collide, words are fused (for example courtyard, which rams together a couple of words, one French and one German, which both had the same meaning and both came from the same root), but there is no need to do that sort of thing with cow, for the term cow has survived the formation of English with its primary meaning intact.
Because cow is such a basic word, it tends to be adopted for other uses, from anything to female animals to bingo players to one of my cats (named Cu, which is Old English for cow). But none of the secondary meanings has changed the original and still most common meaning of cow.
If you want to read up on how the word cow has developed, have a look at its etymology (it’s history). You’ll find that it goes way back to something known as Indo-European, out of which many (most) Indian and European languages have developed. The Indo-European root gwou, meaning cow in the sense of cattle, oxen and milch cows, has been used by more recent languages, including English, to mean the same thing: Bossie.
All this business about other things being called cows is no more than the conventional term being applied to describe other things that we either did not have a word for, or which are similar enough to the conventional use that we borrow. Aside from a few inner city kids, all English speakers know what a cow is, so why try to make a muddle of it. Just because lots of other things are named after cows is no reason to change the basic meaning of cow. The would be throwing the calf out with the milk.
To learn about this sort of stuff, check out the etymological section of http://www2.yourdictionary.com/
Although you will never find a member of the American Dairy Goat Association (or any other person whom I’ve met herding or raising goats) use nanny or billy. To goat folks (at least in the States), a female goat is a doe and a male goat is a buck.
Cecil actually addressed this topic in this thread:
http://www.straightdope.com/classics/a3_097b.html
Yes, yes, I know, it starts out addressing the question: is there seaweed in McDonald’s Milk Shakes. But just follow it!
So then I suppose they call kids “fawns”?
I see that in the article Qadgop referenced Cecil mentioned that “cattle beast” was suggested by many, so that it must be fairly widespread.
Nope. Kids is kids. I’ve never heard a good (or, actually, any) explanation for using doe and buck. I’m just reporting the usage, not justifying it. (Goat raisers are all mad, anyway.)
Any evidence as to whether they were mad before they began raising goats, or just became that way fterward?
Well, my wife has been dotty for years. My sanity began to crumble after she introduced me to farm life.
I could be way off-base on this, but I believe that rabbits and mice are also called does and bucks, and the young are called kits and pups, respectively. I think we just don’t have enough words to go around.
From Cecil’s article, linked to by Qadgop
The next-to-last sentence is not correct; for several birds, the female is the default: duck (generic), drake (male), duck (female); goose (generic), gander (male), goose (female); falcon (generic), tercel/tiercel/tercelet (male), falcon (female).
Conversely, for dogs the male is the default: dog (generic), dog (male), bitch (female). “Dog” is also used for the male of wild canids, e.g. fox (generic), dog-fox (male), vixen (female).
One other interesting point about “cattle”: etymologically, the word means “property,” and is related to “capital” in the financial sense.
Helena is correct that rabbits are referred to as bucks (male), does (female), and kits (young). I dunno about mice!