 
horse_scream.wav
  Author: n_audioman
  License: CC-BY 3.0
  URL: http://www.freesound.org/people/n_audioman/sounds/321697/

horse_whinny.wav
  Author: 3bagbrew
  License: CC-BY 3.0
  URL: http://www.freesound.org/people/3bagbrew/sounds/59569/