The calf extrator?s function has been studied, through measuring traction and how this varies in different situations, in comparison with corresponding manual traction situations. This was done against the background that excessive force at assisted calvings at dystocia can mean life threatening damages on the calf such as grave acidosis, vertebral fractures, femur fractures and rib fractures. The calf extractor has earlier been measured to pull with greater force than the established maximum force of ?two strong men?.