Source : Webster's Revised Unabridged Dictionary (1913)

Foal \Foal\, v.t. [imp. & p. p. {Foaled}; p. pr. & vb. n.
   {Foaling}.]
   To bring forth (a colt); -- said of a mare or a she ass.

Source : WordNet®

foaled
     adj : (used of a horse or related animal) born