We can make a temurah from cattle to [animals of] the flocks, and from [animals of] the flocks to cattle; from sheep to goats, and from goats to sheep; from males to females, and from females to males; from unblemished animals to blemished animals, and from blemished animals to unblemished animals, for it is stated: He shall not exchange it nor shall he substitute it [whether] good for bad or bad for good. What is [the case] of good for bad? [A case of] blemished [animals] whose conse- cration preceded their blemish.  We can make a temurah [by substituting] one [unconsecrated animal] for two [consecrated animals], and two for one, [and even by substituting] one for a hundred, and a hundred for one. R’ Shimon says: One cannot make a temurah except one for one, for it is stated: then it and its substitute [shall be holy]; just as “it” is a single animal, so too its substitute is a single animal.