author(s)
S Jaiswal, I Singh, D Mahanta, S Sathapathy, M Mrigesh, K Pandit and S Tamil Selvan

abstract
The present study was carried out on 24 birds of different age groups of Uttara fowl and elucidates the age-related changes in the heart through gross morphological and gross morphometrical studies. The birds were reared and procured from the Instructional Livestock Farm (ILF), GBPUA&T, Pantnagar and were divided into four age groups viz. day old, 7, 28 and 112 days old. The present research study was undertaken for a period of four months from January, 2017 to April, 2017. Gross morphological studies revealed that the heart of Uttara fowl was located in the cranial part of thoracoabdominal cavity was enclosed by semi-transparent pericardial sac. The shape of the heart of Uttara fowl was like a cone with pointed apex and wide base. As the age advanced this cone becomes less pointed towards the apex. The colour of heart was brownish red which become darken with increase in age. Gross morphometrical studies revealed that there was a gradual increase in body weight of bird which was 37.03±1.58, 49.05±1.21, 179.16±9.16 and 1013.33±58.97grams at the day old, 7, 28 and 112 days respectively. The weight of heart at day old, day 7, day 28 and 112 day bird was 0.32±0.02, 0.43±0.03, 1.52±0.04 and 4.97±0.3 grams respectively, which was around 0.86%, 0.87%, 0.84% and 0.48% of the total body weight of bird at respective age intervals. The length of heart at day old, 7, 28 and 112 days Uttara fowl was 12.41mm, 13.11mm, 23.46mm and 31.71 mm respectively indicating that there was a gradual increase in length of heart from day old to 112 days old bird. Further, the thickness of the ventricular wall also increased with the advancement of age of the birds.