In the Mishnah on today’s daf (=page) we find that although Rabbi Me’ir rules that an animal that dies in its mother’s womb (or is not fully developed) becomes permitted by means of shehitah performed on its mother, if it is fully developed then it would need its own shehitah. The Hakhamim disagree, arguing that the mother’s slaughter permits the fetus. Rabbi Shimon Shezuri goes so far as to state “even if it is five years old and is plowing the field, the slaughtering of its mother renders it permitted.”
As we have learned (see above, daf 69) the passage in Sefer Devarim (14:6) that defines a split-hooved animal as kosher is understood as teaching that cattle – behemah – can be eaten when found in cattle – ba-behema. While the Hakhamimapply this even to the case of a viable animal that lives outside of its mother’s womb, Rabbi Me’ir rules that such an animal would become permitted only if could not have ritual slaughter performed on its own. (All agree that if the mother had not been slaughtered properly and the fetus survived, it could be slaughtered on its own.)
Rashi explains Rabbi Me’ir’s position as based on his view that full development of the fetus requires it to have its ownshehitah, while the Hakhamim believe that the fetus will require its own shehitah only if it is fully developed and is born. The Ramban disagrees with Rashi, arguing that according to that view, Rabbi Me’ir would have to forbid a fully-developed fetus that dies in its mother’s womb prior to shehitah. His explanation is that the passage in Sefer Devarim permits all the organs in a slaughtered animal – including a fetus. Rabbi Me’ir believes that the live, fully-developed fetus is an exception, since it can have its own shehitah.
Although we accept the Hakhamim’s ruling, nevertheless we require that a fully-developed fetus be slaughtered in the normal way, lest someone become confused about the requirements of shehitah (see Shulhan Arukh, Yoreh De’ah 13:2).