The prohibition of Leviticus 22.28 banning the slaughter of a dam and its young on the same day applies to both father and mother, whereas the rabbis (the majority) hold that it applies solely to the mother (B.T. Hul. 78b). (From The Oxford Encyclopedia of the Dead Sea Scrolls, p.811.)
What, exactly, is a dam? A typoed lamb? Sure, except that lambs are the young in question. A quick search yielded the following answer from answers.com:
Never heard of such a thing? Never even come across it, not in a New York Times crossword puzzle, 6th grade research project, the odd piece of trivia?
dam2 (dăm) n.
(Abbr. d.) A female parent. Used of a four-legged animal.
Archaic. A mother.
Turns out the word isn't as far-fetched as it appears. Its usage is, at best, esoteric, but its lineage is legit, stemming from Middle English dam - dame, lady, mother. See for yourself.