The Collaborative International Dictionary of English v.0.48:

Herder \Herd"er\, n.
   A herdsman. [R.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

Herder
    n 1: German philosopher who advocated intuition over reason
         (1744-1803) [syn: Herder, Johann Gottfried von Herder]
    2: someone who drives a herd [syn: herder, herdsman,
       drover]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "herder":
   cattleman, cowboy, cowgirl, cowhand, cowherd, cowman, cowpuncher,
   drover, gaucho, goatherd, gooseboy, gooseherd, herdsman, hogherd,
   horse wrangler, horseherd, pigman, puncher, sheepherder, sheepman,
   shepherd, shepherdess, swanherd, swineherd, vaquero, waddy,
   wrangler