cowpuncher vs cattleman

cowpuncher and cattleman both are nouns.

Word	Noun	Adjective	Verb	Adverb
cowpuncher	Yes	No	No	No
cattleman	Yes	No	No	No

As nouns, cattleman is a hyponym of cowpuncher; that is, cattleman is a word with a more specific, narrower meaning than cowpuncher:

cowpuncher: a hired hand who tends cattle and performs other duties on horseback
cattleman: a male hired hand who tends cattle and performs other duties on horseback

Other hyponyms of cowpuncher include buckaroo, buckeroo, vaquero, cowgirl, gaucho, horse wrangler, wrangler, roper, cowboy, cowman.

cowpuncher (noun)	cattleman (noun)
a hired hand who tends cattle and performs other duties on horseback	a man who raises (or tends) cattle
	a male hired hand who tends cattle and performs other duties on horseback