The third perek (=chapter) of Masechet Hullin begins on today’s daf (=page). Following the first two chapters of the tractate whose focus was on the act of slaughtering an animal, this perek – the longest one in Masechet Hullin – deals with the animal itself, i.e., which animals are permitted and forbidden to eat. The two general categories discussed are the laws of terefah – animals that for reasons of illness or injury will die as a result of their condition – and types of animals that are not kosher and cannot be eaten.
similar defect could not continue to live, it is a terefah.
In defining this principle, we find a difference of opinion. The accepted interpretation is that the animal will succumb to its condition within 12 months, but others say that it will die within 30 days and one opinion in the Gemara defines it as an animal whose condition will not allow it to conceive and give birth. The commentaries discuss whether an animal would be considered a terefah if it could be treated with drugs, and whether there is reason to distinguish between different types of terefot.
Regarding the language of the Mishnah, some ask why the Mishnah teaches “if an animal with a similar defect could not continue to live, it is a terefah,” rather than simply saying “any animal destined to die of its condition is a terefah.” One approach is to explain that the Mishnah is discussing a case where the animal has already been slaughtered and is found to have an internal injury. Is the animal kosher? The Mishnah teaches that “if an animal with a similar defect could not continue to live, it is a terefah.” The Hatam Sofer suggests that the Mishnah is teaching us that even if we find an out-of-the-ordinary case where the animal survives more than 12 months, if an animal with a similar defect could not continue to live, it is, nonetheless, a terefah.