The University of Georgia
College of Veterinary Medicine
Class of 2019
Characterization and comparison of cell mediated immune responses in stressed and unstressed beef calves
Veronica M. Buhler, Kaycee R. Cash, David J. Hurley, and Brent C. Credille
Food Animal Health and Management Program, Department of Population Health, College of Veterinary Medicine,
University of Georgia, Athens, GA.
The goal of this study was to compare the cell mediated immune responses of multiple source, highly commingled, sale-barn origin calves (STR, n=10) to those of single source calves that had been weaned for 60 days (UNS, n=10). Peripheral blood mononuclear cells (PBMCs) and neutrophils (PMNs) were isolated from jugular venous blood of each calf. PBMCs were stimulated with Concanavalin A, BVDV-1, BVDV-2, BHV-1, M. haemolytica, and P. multocida and evaluated for clonal proliferation and secretion of IFN-g and IL-17 into cell culture supernatants. The native functional capacities of PMNs were evaluated in response to stimulation with Zymosan, S. aureus antigen (SA), lipopolysaccharide (LPS), and peptidoglycan (PGN). Complete blood counts and serum biochemical profiles were performed for each animal at time of sample collection. Compared to STR calves, UNS calves had significantly greater lymphocyte proliferative responses following stimulation with viral and bacterial antigens (P < 0.05). In addition, PMNs isolated from UNS calves had a greater ability to phagocytose E. coli and S. aureus when compared to STR calves. Serum non-esterified fatty acids were significantly higher in STR calves (P < 0.01). Serum b-hydroxybutyrate was significantly lower in STR calves (P < 0.01). These data suggest that immunologic and physiologic differences exist between STR and UNS calves. While the underlying mechanisms for these differences are not clear, it is possible that combinations of energy imbalances, stress-induced immunosuppression, and general immune naivete, may predispose STR calves to an increased risk of morbidity and mortality due to bovine respiratory disease.
Research Grant: The research reported here was supported by the Georgia Agricultural Commodity Commission for Beef.
Student Support: Boehringer Ingelheim, Veterinary Medical Experiment Station, UGA College of Vet Medicine