I have only recently heard this song 'Dona Dona' for the first time, I thought it was a strangley moving song. I came across this page when I was looking for some information about the song. Several people seem to think it's about a woman, my feeling is that it is about a child.
A calf on a wagon bound for market, a child on a train bound for a camp,ect. There are many similarities along these lines through-out the song.
I guess some of the writers on this page will have something to say about that.