• Open Access

Identification of Predictors of Salmonella Shedding in Adult Horses Presented for Acute Colic


  • Drs Dallap Schaer and Aceto contributed equally to the production of this manuscript

Corresponding author: B.L. Dallap Schaer, New Bolton Center, 382 West Street Rd, Kennett Square, PA 19348; e-mail:bldallap@vet.upenn.edu.



Colic has been associated with shedding of Salmonella. Horses with salmonellosis typically develop diarrhea, fever, and leukopenia. Overlooking additional predictors may result in failure to detect shedding horses and increase environmental contamination.


Evaluate associations between signalment and clinicopathologic data during early hospitalization and Salmonella shedding in horses treated for acute colic.


Horses with acute colic admitted to a referral hospital. A total of 59 horses shedding Salmonella compared to 108 Salmonella-negative horses.


Retrospective case-control study evaluating patient and Salmonella culture data. Associations between variables and Salmonella shedding were identified using logistic regression. Two multivariable models were developed pertaining to (1) information available within 24 hours of admission and (2) clinical findings that developed later during hospitalization.


Variables retained for multivariable model 1 indicated that Warmbloods and Arabians had increased odds for shedding Salmonella, as did horses requiring surgery (OR, 2.52; 95% CI, 1.10–5.75) or having more severe gastrointestinal disease (OR, 2.59; 95% CI, 1.08–6.20). Retained variables for model 2 demonstrated that horses that were treated surgically (OR, 1.60; 95% CI, 0.70–3.62), developed fever >103°F (OR, 2.70; 95% CI, 0.92–7.87), had abnormal leukocyte count (OR, 1.38; 95% CI, 0.61–3.09), or became inappetent and lethargic (OR, 16.69; 95% CI, 4.08–68.24) had increased odds for shedding Salmonella.

Conclusions and Clinical Importance

In horses with acute colic that present without signs of diarrhea, fever, or leukopenia, additional predictors associated with shedding Salmonella could be used to more promptly identify horses likely to shed organisms.