Acute left heart failure, a common necropsy finding of an acute feedyard death. The entire lung is grossly enlarged, with impressions of the ribs visible. Similarly, the intralobular spaces are also apparent, suggesting pulmonary edema. When the left side of the heart fails, as with a myocardial infarction, usually in the papillary muscle in cattle the blood backs up into the lung, creating the pathology in this image.