farm animal vs placental mammal

farm animal and placental mammal both are nouns.

Word	Noun	Adjective	Verb	Adverb
farm animal	Yes	No	No	No
placental mammal	Yes	No	No	No

As nouns, placental mammal is a hypernym of farm animal; that is, placental mammal is a word with a broader meaning than farm animal:

farm animal: any animals kept for use or profit
placental mammal: mammals having a placenta; all mammals except monotremes and marsupials

Other hypernyms of farm animal include eutherian, eutherian mammal, placental.

farm animal (noun)	placental mammal (noun)
any animals kept for use or profit	mammals having a placenta; all mammals except monotremes and marsupials