Dog has good days and bad

My 5 yr old boston terrrier had a surgery for linear foreing body on Feb 19.  She had an infection and the incision did not close completely resulting in her having a second surgery to debridle the incision and clean out the infection.  That has healed very nicely, however the problem I have now is, since the surgery she has had some days with diarrhea.  On these days she does not want to eat, she eats lots of grass and then poops gel-covered bunches of grass.  After a day like this she had two or three normal days - normal eating and normal stools.  This happened a few times so I called my vet.  She said I should try feeding some plain nonfat yogurt to improve the bacterial balance in her digestive system (off due to anitbiotics we assume).  I have been doing this for 8 days.  The past 7 days my dog has been doing GREAT!  She had normal stools, normal appetite and her activity level was back to normal.  Today (Mar 28), though, she is acting depressed, she would not eat this morning and did the grass diarrhea thing again.  This afternoon we went on a walk, she acted like normal on the walk, but then regurgitated the food that she ate about 2 hours prior to the walk.  She got into my other dog's food dish and ate kibble and has just now regurgitated this.   My questions are:

What kind of problem could this be?
My vet is closed for the weekend, should I consider this an emergency or wait to see how she is tomorrow?

Your advice is very appreciated!

Lisa

[Aleda M Cheng, D.V.M., C.V.A]

Your dog had a surgery that if she was human would have required several days in the ICU than several days in a regular hospital room, than lord knows how long in Rehab.  We are talking major major surgery here.  It is a risky surgery because there is a very high incidence of infection due to peritonitis.

I am amazed that he did not have more difficulty with recovery.  It is quite normal for her to have good days and bad days until she is completely recovered.

It is perfectly safe to keep your dog on yogurt or yogurt supplements lone term.

[LisaQuint]

I just wanted to add that by evening she was acting more normal again.  Today, Sunday morning, she is eating and acting more normal.  The only other things I am noticing are that she is acting more dominant or "grumpy" towards my other dog this whole weekend, which is not normal for her.  Also, her coat looks a little oily - Maybe from the yogurt?  I am taking her to the vet on Monday for sure - any advice here would be helpful in figuring out this puzzle.

[LisaQuint]

Thanks for the advice.  I now have her on Proviable to try to get things back to normal.  My vet suggested that I bring in a stool sample the next time she has any trouble with diarrhea so we can figure out if we need antiabiotics.  Hopefully the probiotics will do the trick.