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]