The Collaborative International Dictionary of English v.0.48:

Breeder \Breed"er\, n.
   1. One who, or that which, breeds, produces, brings up, etc.
      [1913 Webster]

            She was a great breeder.              --Dr. A.
                                                  Carlyle.
      [1913 Webster]

            Italy and Rome have been the best breeders of worthy
            men.                                  --Ascham.
      [1913 Webster]

   2. A cause. "The breeder of my sorrow." --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

breeder
    n 1: a person who breeds animals [syn: breeder, stock
         breeder]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "breeder":
   atomic pile, breaker, breeder reactor, bricks, broncobuster,
   buckaroo, cattleman, chain reactor, chain-reacting pile,
   cow keeper, cowman, dairy farmer, dairyman, equerry, farrier,
   fast pile, furnace, grazier, groom, heterogeneous reactor,
   homogeneous reactor, horseshoer, hostler, intermediate pile,
   lattice, neutron factory, nuclear furnace, pile, plutonium reactor,
   power reactor, power-breeder reactor, radioactive waste, rancher,
   ranchero, ranchman, reactor, reactor pile, rods, sheepman,
   slow pile, stableboy, stableman, stellarator, stock raiser,
   stockbreeder, stockkeeper, stockman, tamer, trainer,
   uranium reactor