Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 10, 2004
Publication Date: September 1, 2004
Citation: Elsasser, T.H., Ingvartsen, K.L., Kahl, S., Capuco, A.V. 2004. Endocrine effects on immune function with special focus on the periparturient animal [abstract]. Tenth International Symposium on Ruminant Physiology. v. 10:44. Technical Abstract: Birth and parturition, lactation, weaning, castration, and seasonal diet change constitute defined, and for the most part naturally occurring, periods in animals' lives where a needed priority for a specific biological function temporarily challenges the stability of other physiological processes. With the recognition of these periods as potential times of increased risk for homeostatic failure, managers could benefit from the application of intervention strategies to stabilize the internal milieu in a manner where physiological conflicts are minimized as would be the further potential for opportunistic clinical infection and disease. While a tremendous quantity of data has been amassed in attempts to categorize nutritional, hormonal, and immunological perturbations associated with these stresses, clear cause and effect relationships remain elusive and thus biochemically-defined, pathway-based decision structures towards intervention lack in favor of the more traditional treatment of symptoms. Many of the physiological conflicts of this sort can be appreciated in the delicate, but critically balanced state of the periparturient dairy cow. We present here some newer findings and implications regarding hormone interactions and effects suggesting targets towards which intervention strategies could be developed or further explain why some strategies like vitamin E work as well as they do. In particular, the ability for growth hormone to critically regulate the activity of nitric oxide synthases and the metabolic fate of nitric oxide as well as the differential regulation of the multifunctional antimicrobial and anti-apoptotic hormone adrenomedullin in the mammary gland during lactation are discussed.