DA - displaced abomasum. Basically twisted gut.
If the cow in question is getting up and down I think I'd rule out milk fever. Also since she's been fresh a month milk fever would be low on the list of possibilities.
Have a stethoscope? You can check for a DA by putting the stethoscope against her flank and ribs (check all over) and flicking your finger next to the stethoscope. A DA has a characteristic "ping" like flicking a tin can. Check the left side first - if I remember right, about 9 times out of 10, a DA is on the left side, not the right.
How about the rest of the cow's history? calving problems? twins? retained afterbirth? mastitis? What's she eating? grain? hay? grass? free choice? sounds like she's a nurse cow - ?