Bovine surgery guidelines

The surgical guidelines have been developed in response to a survey we completed in 2016 that identified a need for widely accessible antimicrobial guidelines for surgical prophylaxis.

National Research Council’s risk index for surgical infection:

Clean Non-traumatic, uninfected. No break in aseptic technique, no inflammation encountered. Elective, closed primarily and no drain used
Clean-contaminated Controlled entering of a hollow muscular viscus, minor break in aseptic technique
Contaminated Open, fresh traumatic wound. Incision into a site with acute, non-purulent inflammation. Major break in aseptic technique.
Dirty Pus encountered during surgery. Perforated viscus found. Traumatic wound with devitalised tissue, foreign material or faecal contamination, or of more than 4-hour duration


Surgical conditions Mitigating factors Antimicrobial recommendation Duration of therapy
Clean None N/A
Uncomplicated hernia repair75 None N/A
Rumenotomy76,77 Oxytetracycline Preoperatively only
Unsanitary conditions Oxytetracycline Preoperatively only78
Periparturient79,80 Oxytetracycline Preoperatively only78
Surgery >1.5h Oxytetracycline No evidence, in other species preoperatively only
Clean-contaminated Oxytetracycline No evidence, in other species stop by 24h
Contaminated Oxytetracycline No evidence, in other species 24-48h
Dirty Choose appropriate to infection Choose appropriate to infection

Timing of prophylactic antimicrobials:

Tissue levels of antimicrobials are required at the time of first incision to confer protection from surgical site infection.

Intravenous antimicrobials: Administer 30-60 mins prior to surgery

Intramuscular procaine penicillin: 2h prior to surgery

Intramuscular oxytetracycline: ~8 h prior to surgery

Tmax for individual drugs given by different routes can be used to assess optimal timing to achieve peak serum levels at the time of first incision.

Repeat dosing:

Dosing interval should be measured from the time of the preoperative dose. The dosing interval can be calculated as twice the elimination half-life of the antimicrobial.

Intravenous oxytetracycline: 6 hours