Wound infection and postoperative performance after a single intra‐abdominal administration of 9 g sodium ampicillin in cows operated on for caecal dilatation or torsion (n=33) were evaluated. In the 25 animals that left the clinic in good health (76% short‐term survival), no wound infection occurred. Postoperative performance was normal in 21 of these animals (84%). The figures for short‐term survival and postoperative performance are comparable to those from a retrospective study of 169 animals operated on between 1985 and 1990. Single intra‐ abdominal administration of sodium ampicillin during surgery provides good protection against infection without negative effects on the postoperative performance.