LAUSR

INTRODUCTION Mandibular fractures are among the most common fractures in cattle. The medical records of 108 cattle with a mandibular fracture, that were referred to the University of Zurich Veterinary Hospital from 2005 to 2019, were analysed to document the types of treatment, complications and long-term outcomes. Cattle, still alive at the time of retrospective analysis, underwent clinical and radiographic examinations. A fall was the single most common cause of a mandibular fracture (48,1 %), and a third of all cattle had a concomitant disease at the time of referral. Seventy-five cattle (69,4 %) had a single fracture, 26 (24,1 %) had two fractures and seven (6,5 %) had three fractures of the mandible. The molar part of the mandibular body was most commonly (40,7 %) fractured followed by the diastema (23,6 %), the pars incisiva (13,4 %), the ramus (12,1 %) and the symphysis (10,2 %) of the mandible. The majority of cattle (84/108, 77,8 %) had open fractures. Treatment was instituted in 63/108 animals (58,3 %) with 77/148 fractures. Of these fractures, 28 were treated with plate osteosynthesis, 25 with an external fixator, 8 with cerclage wire, 7 using mixed techniques, 4 with fragment excision, 4 underwent conservative treatment and one a mucosal suture. In total, 45/108 animals (41,7 %) were culled because of multiple fractures, concomitant diseases and because of economic reasons. Complications occurred in 34 (54,0 %) treated cattle; 22 had abnormal wound healing of which 18 developed osteomyelitis complicated by a sequestrum (14). Of the treated 63 cattle, 56 (88,9 %) were discharged. The mean postoperative productive life was 46 ± 29,2 months for animals that were deceased at the time of the study. Thirteen of the cattle with a sequestrum remained in the herd for 15 to 92 months (mean, 47 months) and one for 2 months. The life expectancy after treatment did not differ significantly from that of the Brown Swiss and Swiss Holstein dairy cattle populations, where the cattle of this study mainly came from. Eleven cattle were available for long-term follow-up; all had a good general health status but nine had dental abnormalities including missing teeth, steps or enamel points, which did not noticeably affect the body condition of the animals. Surgical treatment of selected mandibular fractures had a favourable prognosis (52/63 healed, 82,5 %) in cattle.