Midrash for Temurah 17:15

6) "good by bad or bad by good": Whole animals by blemished ones, or blemished ones by whole ones. Whence is it derived that "bad" signifies "blemished"? From (Devarim 17:1) "You shall not sacrifice to the L–rd your G d an ox or a sheep in which there is a blemish, any bad thing." "and if he substitutes substitutes": to include women (in the laws of substitution). "and if he substitutes, substitutes": to include the heir. "beast for beast": one (non-sacred beast) for two (sacred ones), or two (non-sacred ones) for one (sacred one), one for a hundred or a hundred for one. R. Shimon says: (One) beast for (one) beast, and not (one) beast for (many) beasts. They said to him: (One) beast is called a beast, and many beasts are called a beast, as it is written (Yonah 4:11) "and many beast."