Jamuna, K.V.Prasad, R.V.Nagaraja, C.S.Chandrashekar Murthy, V.Byre Gowda, S.M.Sathish Kumar, B. M.2016-10-282016-10-282014-09-26http://krishikosh.egranth.ac.in/handle/1/82806PG ThesisTwo cases of schistosomus reflexus (SR), two cases of hydrocephalus and single case of cyclopia, dicephalus and a polydactylism were studied under four categories namely head, neck, thorax and forelimb in cattle. Both SR calves, showed a cleft sternum, exposure of thoracic contents and hypoplasia of lungs and diaphragm. In one calf brachiocephalic trunk originated from left ventricle and common aorticopulmonary trunk from right ventricle, a shunt connecting brachiocephalic trunk with aorta and ventricular septal defect was noticed. Complete absence of left forelimb, and anomalous origin of left subclavian artery from the aortic arch were noticed in the second calf with SR. Two cases of hydrocephalus studied, showed enlarged cranial cavities with dome shaped skull and thinning of cranial bones like frontal, parietal and temporal, enlarged lateral ventricles with thinning of brain parenchyma around it. Cyclopic calf was characterized by single centrally placed orbit containing fused eyeballs, rudimentary eyelids and absence of skeletal structures of nose resulting in lower jaw longer than upper one. Trachea and esophagus sharing a common lumen was a very rare finding, observed in an altodymus dicephalic calf. An additional digit on the medial aspect of both forelimbs noticed in the bull with polydactylism. SR and hydrocephalus might have resulted because of autosomal recessive mode of inheritance, cyclopic condition could be because of interruption in the Shh (Sonic hedgehog) mediated patterning of ventral neural tube. “Y” shaped notochord formation during the process of development may be the probable reason for the dicephalic condition. Polydactylism might be due to the presence of an extra amount of progenitor tissue or due to an abnormal apoptosis of tissue during the development of digits. Studying the congenital abnormalities is the basic step to elucidate the possible cause, apart from adding some valuable information to the field of embryology, it also helps in understanding the normal process of development.enSR, hydrocephalus, cyclopia, altodymus, dicephalic, polydactylism, autosomal recessive, calf, bull.Thesis