Lana get all the soap boxes you can find, I'm climbin up!
Kids, before your first calf is born, buy a calf puller and learn how to properly use it!
Charlie Michaels, retired from KABSU, used to start his lectures with; "The best money you can make is pulling calves". He got everyones attention, and I hope I have yours!
Calving ease is a relative term, and I think alot like Jill. I would have no problem pulling every (first) calf, if I had the opportunity, but some are born unassisted no matter how close I watch. These are the ones I sometimes find smothered in placenta, chilled, or caught under the only low place in the fence. Cows are a whole different matter.
I brake down calving ease into 1\6's, 16% bull genetics, 16% maternal genetics, 16% environment, 16% nutrition, 16% bovine instinct, and 20% human error (just plain stupidity, and that is a whole different thread). The national average death loss is 15%, so please don't stack two of these factors up!
To me calving ease is getting a vigorous, healthy calf up and sucking, by any means short of C-section, without physical harm to it or it's mother