Post-Mortem of a Heifer on Feed

This image depicts a heifer calf found dead on November 18th at 34 days on feed (DOF) with no prior treatment history for undifferentiated fever. Can you diagnose the cause of death?
This case continues our Post-Mortem Series, in partnership with Feedlot Health Management Services, Okotoks, Alberta.
Click to page 2 for the answer and information from the experts at Feedlot Health Management Services.