cattleman vs adult male

cattleman and adult male both are nouns.

Word	Noun	Adjective	Verb	Adverb
cattleman	Yes	No	No	No
adult male	Yes	No	No	No

As nouns, adult male is a hypernym of cattleman; that is, adult male is a word with a broader meaning than cattleman:

cattleman: a male hired hand who tends cattle and performs other duties on horseback
adult male: an adult person who is male (as opposed to a woman)

Other hypernyms of cattleman include cowhand, cowherd, cowpoke, cowpuncher, puncher, man.

cattleman (noun)	adult male (noun)
a man who raises (or tends) cattle	an adult person who is male (as opposed to a woman)
a male hired hand who tends cattle and performs other duties on horseback