Research Summary - 3
A 10-year retrospective study of bovine Salmonella serotypes from UMN VDL cases
| Date/Time: |
8/29/2026
14:30
|
| Author: |
Talita Resende |
| Clinic: |
University of Minnesota |
| City, State, ZIP: |
Saint Paul, MN 55108 |
M.C.V. Cirilo, DVM student
1
;
M. Kikuti, DVM, MS, PhD
2
;
T. Resende, DVM, MS, PhD
1
;
1Veterinary Diagnostic Laboratory, University of Minnesota, Saint Paul, MN, 55018
2Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, 55108
Introduction:
From more than 2,500 serovars within the Salmonella enterica species, Dublin, Cerro, Montevideo, and Typhimurium are considered the most relevant in cattle. In these animals salmonellosis has a significant sanitary and productive impact, and for public health it poses risks related to foodborne diseases. For this reason, long-term monitoring of Salmonella serovars is essential to better understand their zoonotic potential and to establish effective biosecurity measures. The present study aimed to characterize the prevalence and temporal distribution of bovine Salmonella serovars over a 10-year period (2015–2025).
Materials and methods:
A retrospective analysis was performed on bovine cases submitted to the Veterinary Diagnostic Laboratory at the University of Minnesota (UMN VDL). The selection criteria were: bovine cases submitted between 2015 and 2025 that tested positive for Salmonella spp. by bacterial culture. Descriptive data analysis was performed using Stata 18. In total, 967 cases were included in the data analysis, yielding 2,440 positive samples (2.52 positive samples per submission). Among the 2,440 samples analyzed, 77.50% (1,891) originated from dairy production systems, 1.76% (43) were from beef herds, and 20.74% (506) originated from submissions without a declared production system. Therefore, due to the greater representativeness of cases from dairy systems, subsequent analyses were conducted considering only samples derived from this production type.
Results:
From the 1,891 Salmonella isolates that originated from dairy production systems, 766 were serotyped. The most prevalent serovars were Dublin (45.6%, n = 349), Cerro (17.1%, n = 131), and Montevideo (13.3%, n = 102), which remained the dominant serovars throughout the 10-year study period and across different sample types submitted. In contrast, Salmonella Typhimurium, recognized for its high zoonotic potential, was detected in only 20 cases between 2015 and 2025. Age distribution showed that infections were more frequent in young animals, with calves aged up to 2 months accounting for the majority of positive samples (57.16%, n = 1,081). In comparison, fewer cases were observed in older age groups (7–12 months: 47; 13–24 months: 49; >24 months: 135), suggesting greater exposure and susceptibility to disease in neonatal and pre-weaned calves. Additionally, variation in serovar distribution according to age was observed: in animals up to 12 months of age, the most frequent serovars were Dublin and Cerro, whereas in animals older than 12 months, serovars Cerro and Montevideo predominated, with no cases of serovar Dublin detected.
Significance:
Salmonella enterica serovars Dublin and Cerro were the predominant serovars in dairy cattle samples submitted to the UMN VDL over a 10-year period, with higher occurrence of cases in calves younger than 2 months-old. The characterization of these serotypes over a decade contributes to a better understanding of infection dynamics, providing a basis for the development of more effective control strategies to reduce the impact of the disease on productivity and public health.
