One of the most critical elements of operation for a major equine hospital is biosecurity, which can be challenging for facilities treating critically ill patients. Horses recovering from acute colic or colic surgery are among the most medically vulnerable to secondary illness, due in part to environmental and physical stressors, as well as potentially undergoing general anesthesia and a major abdominal surgery.

Researchers at the University of Pennsylvania’s New Bolton Center recently completed a study examining the link between acute colic and Salmonella shedding. Horses with salmonellosis often have obvious signs of diarrhea, fever, and low white blood cell count (termed “leukopenia”). But researchers estimate that 1-2% of clinically normal horses shed the bacteria in their feces. This number likely rises when horses are stressed, as they would be following an acute medical or surgical colic episode.

While most large animal hospitals conduct fecal culture testing to identify potential Salmonella shedders, test results can take several days to return, which might not allow veterinarians to begin the necessary biosecurity protocols immediately.

To identify warning signs of horses shedding Salmonella, the research team–led by Barbara Dallap-Schaer, VMD, Dipl. ACVS, ACVECC–examined the medical records of 59 Salmonella-positive horses and 108 Salmonella-negative horses admitted to New Bolton Center. Only horses admitted for acute colic without diarrhea at presentation were included in the study.

The team found that Salmonella-positive horses not exhibiting signs of diarrhea at pres