Hypothesis 2:

Forced extraction with calf chains and a calf pull during difficult parturition is a common cause of injury to the forelimbs of calves.  Typically the chains are wrapped around the fetlock joint and pressure is applied to the metacarpus to extract the calf from the birth canal.  A fracture of the metacarpus is a common sequelae of difficult deliveries.  The fracture expected is described in hypothesis 1.
The hyperextension of the left metacarpal phalangeal joint could be due to a congenital deformity.