A yearling Jersey heifer was presented to Cornell University's Farm Animal Hospital for mandibular swellings. Radiographs, ultrasound, and CT revealed fractures, osteomyelitis, and an abscess involving much of the right hemi-mandible. The heifer was treated with drainage of the abscess and systemic antibiotics (oral rifampin and subcutaneous procaine penicillin G). The owner reported improvement in comfort and swelling 10 days after discharge.