In young animals the long bones in the body are made of three bony parts which fit almost perfectly together at the growth plates. The shaft of the bone is one part and the two ends are the other two parts. In your bone the end on the right is missing because the animal was young and the two parts had not perminently attached as they would have done in an adult. The other end of the bone has attached. I think this is a Tibia, or shin bone, from either a pig or cow depending on the size.