milch cow vs dairy cattle

milch cow and dairy cattle both are nouns.

Word	Noun	Adjective	Verb	Adverb
milch cow	Yes	No	No	No
dairy cattle	Yes	No	No	No

As nouns, milch cow and dairy cattle are synonyms defined as:

Other synonyms of milch cow include dairy cow, milcher, milk cow, milker.

milch cow (noun)	dairy cattle (noun)
cattle that are reared for their milk	cattle that are reared for their milk