Post-mortem examination and histopathological analysis of tissues collected from infant eastern cottontail rabbits (Sylvilagus floridanus) in rehabilitation

Pauline Kosmal; Shoshanah Jacobs; Wendy Pearson; Trevor DeVries; Sherri Cox

doi:10.53607/wrb.v44.301

Authors

Pauline Kosmal University of Guelph, Guelph, Ontario, Canada
Shoshanah Jacobs University of Guelph, Guelph, Ontario, Canada
Wendy Pearson University of Guelph, Guelph, Ontario, Canada
Trevor DeVries University of Guelph, Guelph, Ontario, Canada
Sherri Cox University of Guelph, Guelph, Ontario, Canada; National Wildlife Center, Caledon East, Ontario

DOI:

https://doi.org/10.53607/wrb.v44.301

Keywords:

Eastern cottontail, Histopathology, Inflammation, Lesions, Necropsy, Post-Mortem, Subclinical, Sudden death, Tube feeding

Abstract

Young eastern cottontail rabbits (Sylvilagus floridanus) are commonly admitted to wildlife rehabilitation centers and often carry a guarded prognosis, even those who appear healthy on admission. For this research, necropsies and histopathological analysis were performed to attempt to determine the cause of death of infant eastern cottontails who died suddenly in care without clinical signs of illness. A total of 26 cadavers were collected in 2022 and 2023, with an average body weight on admission of 76.8 ± 4.4 g. Freeze-thaw artifacts and cell autolysis limited findings in the tissues. However, pre-mortem lesions were found in the heart (n = 5), liver (n = 5), large intestine (n = 1), small intestine (n = 2), and lungs (n = 3). These were mostly inflammatory or bacterial in nature. An unexpected but important finding was that six of the cadavers had milk present in their lungs, likely the result of tube-feeding errors, which may have resulted in the deaths of these rabbits. Other results suggest a systemic response to bacteria and inflammation, and dysbiosis could not be ruled out in some cases.

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Author Biographies

Pauline Kosmal, University of Guelph, Guelph, Ontario, Canada

Pauline Kosmal, PhD is a postdoctoral fellow and comparative animal nutritionist in the Department of Animal Biosciences. She is a NWRA committee member.

Shoshanah Jacobs, University of Guelph, Guelph, Ontario, Canada

Shoshanah Jacobs, PhD is a professor in the Department of Integrative Biology. They have broad research interests and enjoy taking mixed-method approaches to answer complex questions.

Wendy Pearson, University of Guelph, Guelph, Ontario, Canada

Wendy Pearson, PhD is an associate professor and the graduate coordinator in the Department of Animal Biosciences. Her main research focus is treating inflammatory diseases in horses and has a broad interest in all aspects of animal health and welfare. Wendy is also partnered with the Canadian Society of Animal Science.

Trevor DeVries, University of Guelph, Guelph, Ontario, Canada

Trevor DeVries, PhD is a professor in the Department of Animal Biosciences. He is an applied researcher in the field of animal welfare, with a focus on dairy cattle behaviour. Trevor is partnered with the International Society for Applied Ethology and the Canadian Society of Animal Science.

Sherri Cox, University of Guelph, Guelph, Ontario, Canada; National Wildlife Center, Caledon East, Ontario

Sherri Cox, DVM, PhD is an assistant professor in the Department of Integrative Biology and Medical Director at the National Wildlife Center. She is a licensed wildlife veterinarian, authorized wildlife rehabilitator in Ontario, and NWRA board member.

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