tn Heb “and every opener [of a womb].”
tn The conditional clause uses an imperfect tense; this is followed by a perfect tense with the vav consecutive providing the obligation or instruction. The owner might not redeem the donkey, but if he did not, he could not keep it, he had to kill it by breaking its neck (so either a lamb for it, or the donkey itself). The donkey could not be killed by shedding blood because that would make it a sacrifice, and that was not possible with this kind of animal. See G. Brin, “The Firstling of Unclean Animals,” JQR 68 (1977): 1–15.
tn Heb “and every firstborn of man among your sons.” The addition of “man” is clearly meant to distinguish firstborn humans from animals.