sheep rot vs black disease

sheep rot and black disease both are nouns.

Word	Noun	Adjective	Verb	Adverb
sheep rot	Yes	No	No	No
black disease	Yes	No	No	No

As nouns, sheep rot and black disease are synonyms defined as:

sheep rot and black disease: a disease of the liver (especially in sheep and cattle) caused by liver flukes and their by-products

Other synonyms of sheep rot include distomatosis, liver rot.

sheep rot (noun)	black disease (noun)
a disease of the liver (especially in sheep and cattle) caused by liver flukes and their by-products	a disease of the liver (especially in sheep and cattle) caused by liver flukes and their by-products