Administration of perioperative penicillin reduces postoperative serum amyloid A response in horses being castrated standing.

The research study focused on the effects of giving horses penicillin before surgery to reduce post-operation inflammation as indicated by the acute phase protein serum amyloid A (SAA). It found that horses that received penicillin showed fewer signs of inflammation and surgical complications as compared to those only given anti-inflammatory medication.

Methods

• The researchers carried out a randomized clinical trial on 50 stallions that were to be castrated.
• SAA levels were measured on the 0, 3rd and 8th day post-surgery. Six horses that showed elevated SAA concentrations before the surgery were excluded from the study.
• Of the remaining 50 stallions, 26 were administered non-steroidal anti-inflammatory drug (NSAID) therapy and 24 were given both NSAID and 25,000 U/kg procaine penicillin over the first three days after the surgery.

Results

• SAA levels increased noticeably from their pre-surgical levels in both groups.
• By the 8th day after the surgery, horses that had only received NSAID therapy showed significantly higher SAA levels, thus indicating higher inflammation, as compared to horses that were given both penicillin and NSAID therapy (P<.02).
• Horses that had had higher SAA concentrations pre-surgery (the six excluded horses) exhibited more infectious complications than those with normal pre-surgery SAA levels.

Conclusion

• The postoperative SAA response was reduced when applying perioperative antimicrobial therapy, leading to the speculation that bacteria were present in the surgical wound which contributed to postoperative inflammation.
• Horses with elevated preoperative SAA concentrations were more prone to developing infectious complications post-operation than horses with normal preoperative SAA concentrations.
• The administration of antimicrobials could be significant for horses being castrated standing under field conditions.
• Increased SAA concentrations could potentially be an indicator of increased surgical risk in horses, thus it could be useful in surgical planning for the elective surgery of horses.