I appear to have a few different thoughts on this situation then most folks. If you expend as much energy and time as you can and can;t find the calf it's one of those harsh realities of the cattle business.
Had a cow that calved, saw the the calf and it disappeared under the hotwire into the woods. No big deal, klots of the calves duck into the edge of the woods and hide out. Didn;t see her again that day so had the neighbors come over and we walked every square inch of that ppiece of woods, only about 20 acres, never found the calf. Next morning cow still in the same place calling the calf. Searched the woods again, no luck. Started checking other areas to see if the little snot had just wandered off. When I got back the cow was contentedly grazing. That evening, same thing. Cow in the same spot along the fence calling and no calf. Searched even more, still no calf. First light the next morning I searched every square inch of the farm, I thought, finally gave up. Came back from the furthest part of the farm and the calf was nursing. I watched the little butthead. She wandered into the woods in the same spot the cow had been standing and calling. Watched the calf go into the woods, slip through the trees, go down a hill into a ditch and cram herself under a MF rose. I knew right where she was and it still took a couple of minutes to be able to spot an eye, that's all I saw, an eye. Next day she joined the herd but would wonder off over a quarter mile into the woods to bed down.
If the pack of dogs that used to run this place had come through and found her she would have been dead, or if she couldn;t have fought her way out of the MF rose the same resulsts.
All you can do is what you can do. Beat yourselves up for having a calf die, but it's still part of the business.
dun