fowl cholera vs septicemia

fowl cholera and septicemia both are nouns.

Word	Noun	Adjective	Verb	Adverb
fowl cholera	Yes	No	No	No
septicemia	Yes	No	No	No

As nouns, septicemia is a hypernym of fowl cholera; that is, septicemia is a word with a broader meaning than fowl cholera:

fowl cholera: an acute diarrheal disease (especially of chickens) caused by the microorganism that causes hemorrhagic septicemia
septicemia: invasion of the bloodstream by virulent microorganisms from a focus of infection

Other hypernyms of fowl cholera include blood poisoning, septicaemia, animal disease.

fowl cholera (noun)	septicemia (noun)
an acute diarrheal disease (especially of chickens) caused by the microorganism that causes hemorrhagic septicemia	invasion of the bloodstream by virulent microorganisms from a focus of infection