Energy Balance, Immune System Function, and Susceptibility to Mastitis in Dairy Cows
The studies proposed for this dissertation evaluate the relationship between energy status and immune system function at the whole animal, protein, and genomic levels, as well as via the utilization of a large-scale epidemiological dataset. Our large-scale study indicated the potential use of circulating non-esterified fatty acids as a predictor of mastitis during early lactation. Dietary-induced negative energy balance (NEB) models, regardless of severity and duration, do not seem to reflect studies that have observed more significant correlations among energy balance, circulating metabolites, and increased susceptibility to mastitis observed in dairy cows during postpartal NEB. Growing evidence indicates the glucose is the primary, if not the only, fuel source used by phagocytes during the immune response. Serum glucose concentrations were greater than those of cows experiencing postpartal NEB, which may at least partially explain the lack of effects observed in this study. Using large-scale studies and the most recent technological advances in immunology and genomics, this dissertation provided further insight into the effect of NEB on immunity in Holstein dairy cows that primarily involved altering the acute phase response, the pro-inflammatory response via NF-kappaB signaling, and antigen presentation via the major histocompatibility complex type II. Future studies characterizing the transcriptomic-level profiles in mammary epithelial cells and immune cells of cows during the transition period will provide additional information on the mechanistic links between postpartal NEB and risk of mastitis.
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign