|Kehrli Jr, Marcus|
|Kimura, Kayoko - IOWA STATE UNIV., AMES|
Submitted to: International Conference on Production Diseases in Farm Animals
Publication Type: Abstract Only
Publication Acceptance Date: August 25, 1998
Publication Date: N/A
Technical Abstract: Periparturient cows are immunosuppressed. Critical neutrophil functions (egress and phagocytic activities) and lymphocyte functions (immunoglobulin and cytokine secretion) are all impaired during the periparturient period. Exact causes of periparturient immunosuppression are not known but some nutritional factors have been evaluated for their influence. Periparturient cows experience large changes in plasma concentrations of vitamins A, D and E, and also are adjusting to the calcium, energy and protein demands necessary for lactation. We recently evaluated the immunological effects of cationic vs. anionic diets on periparturient cows supplemented with vitamin E or not. Vitamin E supplementation resulted in decreased neutrophil Fc receptor-mediated bacterial ingestion and cytotoxicity activities. But it also increased neutrophil chemotaxis and myeloperoxidase activity. Anionic diets resulted in lower neutrophil production of superoxide anion and myeloperoxidase activity. Recent studies have investigated the influence of lactation on selected immune functions in the periparturient cow. Mastectomized cows recover from periparturient suppression of neutrophil myeloperoxidase activity within 1 wk after calving, whereas intact cows remain suppressed for 2-3 wk. Interferon-gamma and IgM production by lymphocytes is less impaired in mastectomized cows and recovers more quickly after calving than what was seen in intact cows. These data suggest that proper nutritional managment of periparturient cows will minimize the magnitude and duration of immunosuppression experienced by dairy cows and thus may reduce the incidence of infectious disease in early lactation.