The Collaborative International Dictionary of English v.0.48:

Ablactate \Ab*lac"tate\, v. t. [L. ablactatus, p. p. of
   ablactare; ab + lactare to suckle, fr. lac milk.]
   To wean. [R.] --Bailey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ablactate
    v 1: gradually deprive (infants and young mammals) of mother's
         milk; "she weaned her baby when he was 3 months old and
         started him on powdered milk"; "The kitten was weaned and
         fed by its owner with a bottle" [syn: wean, ablactate]