Sudden death caused by diaphragmatic rupture following rib fracture in a female sika deer (Cervus nippon) at a zoo

A one-year-old female sika deer died suddenly with no preliminary signs during exhibition at a zoo. At necropsy, the carcass was emaciated and had dried fur. Examination of the thoracic cavity revealed a diaphragmatic rupture measuring 2 cm in diameter and a fracture in the middle of the right eighth rib. The liver and lungs had irregular circular discolorations caused by diaphragmatic rupture and subsequent herniation. Dark-brown-colored ascitic fluid, hydrothorax, and yellowish hydropericardium were also observed. The cause of death was determined to be diaphragmatic rupture caused by a rib fracture, which led to respiratory imbalance and circulatory disorders.