Embryonic Development of Heart in Indian Buffalo (Bubalus bubalis)

The present study was conducted on 35 buffalo foetuses from 0.9 cm CVRL (32 days) to 99.5 cm CVRL (298 days) to observe the morphogenesis and histogenesis of heart. The study revealed that, in 0.9 cm CVRL buffalo foetus, heart was unseptated and tubular which was clearly divided into common atrial chamber dorsally, primitive ventricles ventrally, primitive outflow tract with bulbous cordis region proximally, and aortic sac distally at 1.2 cm CVRL. Septum primum appeared at 1.9 cm CVRL whereas the truncal swellings and fold of interventricular septum appeared at 2.5 cm CVRL foetus. At 3.0 cm CVRL septum primum, endocardial cushions, septum secundum, and foramen ovale were observed. At 7.6 cm CVRL the endocardial cushions fused to form right and left atrioventricular openings and ventricular apex became pointed. Interventricular canal was obliterated and four-chambered heart was recognised along with atrioventricular valve, chordae tendineae, and papillary muscles in 8.7 cm CVRL (66 days) buffalo foetus. The endocardium as well as epicardium of the atria was thicker as compared to ventricle, whereas the myocardium of atria was thin as compared to ventricles in all the age groups. All the internal structures of heart were well differentiated from 50 cm CVRL onwards. The detailed structural components of buffalo heart during prenatal period have been discussed in the present paper.