Post-Hatch Tracheal Morphology and Morphometry in Uttara Fowl

Abstract

Twenty-four healthy Uttara fowl, native to the hilly regions of Uttarakhand, were grouped into four age groups (0, 7, 28, and 112 days), with six birds in each group. The objective of this study was to describe the anatomy of the trachea and to assess the morphological and morphometrical changes after hatching. The trachea was found to be a long, flexible tube with a cylindrical appearance. The trachea continued along the right side of the neck, ventral to the oesophagus. The trachea then entered the thoracic cavity and was finally continuous with the syrinx at the caudal border of the base of the heart. The number of tracheal rings ranged from 101 to 128, and the rings were flattened dorsoventrally. The muscles surrounding the trachea included cleidotrachealis, tracheolateralis and sternotrachealis. Tracheolateralis was a paired muscle that originated from the caudolateral aspect of the cricoid cartilage and was inserted into the first bronchial cartilage of the syrinx. The sternotrachealis muscle was a paired, thick, cylindrical and broad skeletal muscle that extended from the costal process of the sternum (craniolateral process) to the caudal rings of the trachea. As the age of the birds increased from 0 to 7 days, the mean length of the trachea gradually increased. A significant increase was observed from 28 to 112 days of age in Uttara fowl. A gradual increase in the cranial and middle tracheal diameters was observed from 0 to 7 days, whereas a significant increase was observed from 28 to 112 days of age. A non-significant change was observed in the diameter of the caudal part of the trachea from 7 to 112 days.