Ossification of trachea in Kuttanad ducks (Anas platyrhynchos domesticus)

A developmental study of the ossification of trachea in Kuttanad ducks was undertaken using 78 female Kuttanad birds from day-old to 24 weeks of age. The material was collected from six birds in each group at fortnightly interval. Cartilage and bone were differentiated in whole-mount preparations with toluidine blue-alizarin red S staining after formalin, acetic acid and alcohol (FAA) fixation. Trachea started showing small foci of ossification by eighth week. By tenth week, all the tracheal rings were ossified ventrally. The process of ossification progressed with advancing age. By 24 weeks, although whole of the trachea was ossified, but the degree of ossification was lesser on its dorsal side.