What is the Best Postoperative Antibiotic Choice for Cats and Dogs Having Gastrointestinal surgery?  

There is no “one size fits all” answer.  Gastrointestinal surgery is clean-contaminated.  For the majority of clean-contaminated procedures, perioperative antibiotic prophylaxis is all that is necessary.  In our hospitals, Cefazolin given at induction (<30 minutes before skin incision) and every 90 minutes for procedures lasting that long is the norm.

The continuation of antibiotic therapy beyond this duration does nothing to prevent dehiscence or peritonitis, it only makes it harder to diagnose.  Postoperative antibiotic therapy is known to decrease appetite and/or cause vomiting and diarrhea.  Post-op antibiotic therapy may also normalize a temperature that would increase with dehiscence as well as decreasing the presence of organisms in effusion that would allow us to diagnose leaking.

In addition to contributing to the development of antibiotic resistance, unnecessary therapy ultimately, and somewhat counter-intuitively, only serves to delay therapy in patients that may have suffered dehiscence and worsen the patient’s prognosis.  Instances where postoperative antibiotic therapy would be warranted are those where the wound is upgraded from clean-contaminated to contaminated or dirty or those with pre-existing peritonitis or effusion.  In these instances, broad-spectrum therapy ideally based on culture and sensitivity should be provided.


  1. Brown DC, et al. Epidemiologic evaluation of postoperative wound infections in dogs and cats. J Am Vet Med Assoc May 1997 210(9):1302-1306.
  2. Nicholson M, et al. Epidemiologic evaluation of postoperative wound infection in clean-contaminated wounds: A retrospective study of 239 dogs and cats. Vet Surg. Nov-Dec 2002 31(6):577-581.