Ali Baniadam - Department of Surgery,Faculty of Veterinary Medicine, Shahid Chamran University, Ahvaz, Iran.
Fereidoon Saberi Afshar - Department of Surgery,Faculty of Veterinary Medicine, Shahid Chamran University, Ahvaz, Iran.
Ali Reza Ghadiri - Department of Surgery,Faculty of Veterinary Medicine, Shahid Chamran University, Ahvaz, Iran.
Zahra Karimi Jalalabadi - Graduated from the Faculty of Veterinary Medicine, Shahid Chamran University, Ahvaz, Iran.

Objective- To evaluate tail vertebra as an autogenous cortical bone and cancellous bone for filling ulnarsegmental bone defect in dogs. Design- Experimental study. Animals- Eight adult mongrel dogs with an average age of ۳۷.S months and average body weight of۱۷.۶۲ kg. Procedure- The animals were randomly divided into two groups. A bone defect (۲.S-cm) was created on the middle portion of the right ulna in all dogs. Ulna was fixed by intramedullary pinning. In ۵ dogs (test group) ulnar bone defects were filled with tail vertebra, after tail docking. Cancellous bone harvested fromthe il iac cres t was also used to promote bone healing in the ho st-graft inter face s. In the other ۳ dogs(control group) ulnar bone defect s were not filled. Po stoperative clinical assessment was includ edmeasurement of body temperature, heart rate, respiratory rate, and evaluation of the degree of lameness. Radiographic assessment of bone based on the process of bone healing and consolidation of the host-graft interface, periosteal reaction, and soft tissue swelling were performed immediately and at the weeks ۱, ۳, S,۷, ۱۰, ۱۳ and ۱۷ after surgery.