We had one do that a few years back, she calved in January, went down in April. Other than not being able to get her back legs under her, she was healthy. Ate and drank everything I carried to her, the calf would nurse her as she laid there. She never did get up, after two weeks I finally had her put down. Can't rightly remember what we did with the calf, though. Either sold it or let it steal from the other cows.