Administration of perioperative penicillin reduces postoperative serum amyloid A response in horses being castrated standing.
Authors: Busk Peter, Jacobsen Stine, Martinussen T
Journal: Veterinary surgery : VS
Summary
# Perioperative Penicillin and Inflammatory Response in Standing Castration Standing castration under field conditions carries inherent infection risk, yet antimicrobial protocols remain inconsistently applied in equine practice. Busk and colleagues investigated whether perioperative procaine penicillin administration could modulate the postoperative inflammatory cascade by measuring serum amyloid A (SAA)—a sensitive acute phase protein—in 50 stallions randomised to receive either NSAIDs alone or NSAIDs combined with penicillin (25,000 U/kg on days 0, 1, and 2). By day 8 post-castration, horses receiving penicillin showed significantly lower SAA concentrations than the NSAID-only group (P<0.02), indicating reduced systemic inflammation, whilst importantly, six stallions with elevated preoperative SAA developed infectious complications at substantially higher rates than those with normal baseline values (P<0.01). These findings suggest that bacterial colonisation of the surgical site contributes measurably to postoperative inflammation even in uncomplicated cases, and that baseline SAA measurement may help identify high-risk candidates requiring more aggressive antimicrobial cover before elective procedures. For field-based practitioners performing standing castrations, this work supports routine perioperative antibiotic administration and highlights the value of preoperative inflammatory screening to stratify surgical risk.
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Practical Takeaways
- •Consider perioperative penicillin administration in horses undergoing standing castration under field conditions, as it reduces postoperative inflammation and likely infection risk
- •Measure preoperative SAA concentrations as a simple risk assessment tool before elective surgery—elevated baseline SAA predicts higher infection complication rates
- •NSAIDs alone are insufficient for infection control in standing castrations; antimicrobial coverage provides additional protection against bacterial wound contamination
Key Findings
- •Perioperative procaine penicillin significantly reduced postoperative serum amyloid A (SAA) concentrations on day 8 compared to NSAID alone (P<0.02)
- •Horses with elevated preoperative SAA concentrations developed infectious complications significantly more frequently than those with normal preoperative SAA (P<0.01)
- •SAA concentrations increased significantly from preoperative levels in both treatment groups following standing castration
- •Perioperative antimicrobial therapy reduced postoperative inflammatory response, indicating bacterial contribution to post-castration inflammation