In the U.S. cow is used for either sex of Bos Taurus (and the plural is cattle)
Well being a city folk-- i use Cows--for the plural too. "look, there are cows in the field" But beyond that, cows are milk cows-- and cattle are beef. So here in NY--on Long Island and upstate NY, dairy country, there are cows in the field. but when i went out to Texas, or cross country-- i saw cattle.
And for me, cows are female-- they have large, obvious udders.. (that how you know they are cows!) sometimes you'll see a bull in a field with some cows.. udderly devoid of cow like looks...
but cattle are those Bos Taurus that are not as obviously sexed--(most of my experience with cows is from a car going 50 m/p/h past a field.. i don't claim to have had much real contact with farm animals.)
With out an large udder, at 50m/p/h, a cow is hard to tell from a bull--and a herd of them become cattle.
