Submitted to: Proceedings of the Southwest Nutrition Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/2/2013
Publication Date: 2/20/2013
Citation: Carroll, J.A., Sanchez, N.C. 2013. The physiology of stress and effects on immune health in ruminants. Proceedings of the Southwest Nutrition Conference. 2013 Southwest Nutrition and Management Conference Pre-Conference Symposium, February 21, 2013, Tempe, Arizona, p. 35. Interpretive Summary: Scientists from the Livestock Issues Research Unit have been conducting immune challenge studies in cattle for nearly a decade in an effort to elucidate the relationships between stress and immunity, and how these biological processes are influenced by factors such as animal temperament, sex, and nutritional supplements. Utilzing our bovine endotoxemia model generated by administering an E. coli-derived lipopolysaccharide (LPS) to cattle, we have discerned individual variations in the stress and innate immune responses associcated with both natural variations as well as variations associated with different management strategies. Ultimately, the combined immunological effects of cortisol and catecholamines secreted during the stress response result in a well-orchestrated event designed to prevent over-stimulation of innate immunity while simultaneously priming the acquired immune response. Therefore, the final type of immune response that prevails within an animal is dependent upon the overall type and duration of the stress response in the animal. Continued research efforts into these complex interactions may allow the implementation of alternative management practices, improved selection programs, and/or implementation of various nutritional strategies to prevent or overcome significant production losses and animal health care costs for livestock producers. Therefore, this information will be of interest to both scientists and producers working in the area of beef cattle production and beef cattle health with specific focus on the regulation of stress and immune responses.
Technical Abstract: As researchers have continued to explore the complex interactions among stress and production parameters such as growth, feed efficiency, and health, multidisciplinary efforts have emerged leading to a greater understanding of homeostatic regulation. The immune system can be regulated by several different endocrine secretions, with the most prominent being those secreted in response to stress. Ultimately, within the animal, the immune system response to stress is dependent upon the type of stress encountered (i.e., acute versus chronic). Given that the innate immune system provides the first line of defense, understanding the effects of stress hormones on innate immunity holds a great deal of potential with regard to improving cattle health, and ultimately productivity. Our laboratory has utilized a reliable endotoxemia model generated by administering an E. coli-derived lipopolysaccharide (LPS) to livestock as a means to discern individual variations that exist in the innate immune and stress responses that can have a significant impact on the overall health and productivity of an animal. Utilizing this model, we have characterized both natural and management induced variations in the stress and innate immune responses following exposure to LPS in cattle. The focus of this manuscript is on the relationship between the stress and innate immune responses in cattle, and how acute versus chronic stress respones alter immune function.