I have a pasture similar and have used as Doug describes.    Sometimes I calve on it, which I am currently doing this year.    I lost one cow a couple years ago for unknown reasons.    When I found her she was dead with a live newborn calf by her side.  

I don't know if her death was because of some complication of the birth, or possibly grass tetany.   It did not appear she had died from getting too far over on her back.

  The weather conditions at the time were like we are experiencing currently, long cool wet periods with lots of lush new green growth and no sun.  I have loose TM salt with EDDI with some magnesium oxide mixed in it for grass tetany.   I didn't put much in it but the cows seem to be ignoring the salt right now anyway.

Good luck, and welcome to ranchers!