The vet had to make an incision into the stomach due to a flipped stomach and some bacteria must have got in the cut and caused and abcess. All I know is that a few weeks earlier that cow had a flipped stomach and had to have an incision in his stomach and then a few weeks later she died and her body cavity had a us all in it. All the vet said was that it was an internal abcess. That vet wasnt very popular or experienced and she ended up moving... I actually dont have a vet now.... my recent vet just became a NY state vet and now I am vetless.