Well, the news is so-so. :-\
Here's what my vet wrote:
Hazel had abdominal adhesions, most likely related to her spay procedure. Adhesions are an unfortunate, but common complication of abdominal surgery. Hazel's adhesions were around the colon, most likely causing her abdominal discomfort. The adhesions were broken down today, hopefully alleviating her discomfort; they may, however, recur. The discharge cannot be explained by the abdominal findings.