The Collaborative International Dictionary of English v.0.48:

Stockman \Stock"man\, n.; pl. Stockmen.
   A herdsman; a ranchman; one owning, or having charge of,
   herds of live stock. [Australia & U.S.] --W. Howitt.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stockman
    n 1: farmer who breed or raises livestock [syn: stockman,
         stock raiser, stock farmer]