Sorry to hear of your loss, HD. I am in the hills and them going caste is always a concern here.
I found one yesterday morning that had laid down to calve with her head downhill, dead calf behind her (also a nice heifer), and her eyes rolling. Neighbor and I got her turned over and she recovered later in the day. I should have put her in the corral when I saw her water the evening before. I may do that with heifers from now on. However as you found, something else can happen.
On the positive side that is a nice new heifer calf in your picture. Some thing to build on.
I had another cow have a nice calf shortly after turning the heifer so need to look at the positive side.
The problem with cattle though, compared to hogs for example, is that with one calf per year EVERYTHING takes so long. Any breeding improvements can take years to show up. Glad to hear your herd is moving the way you want.
Stuff just happens some times. Look at the positives. They usually outweigh the negatives.
Jim