cattleman vs cowherd

cattleman and cowherd both are nouns.

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

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

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

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

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