anestrum vs anestrus

anestrum and anestrus both are nouns.

Word	Noun	Adjective	Verb	Adverb
anestrum	Yes	No	No	No
anestrus	Yes	No	No	No

As nouns, anestrum and anestrus are synonyms defined as:

anestrum and anestrus: applies to nonhuman mammals: a state or interval of sexual inactivity between two periods of estrus

Other synonyms of anestrum include anoestrum, anoestrus.

anestrum (noun)	anestrus (noun)
applies to nonhuman mammals: a state or interval of sexual inactivity between two periods of estrus	applies to nonhuman mammals: a state or interval of sexual inactivity between two periods of estrus