|Kimura, Kayoko - IOWA STATE UNIV., AMES|
|Kehrli Jr, Marcus - PFIZER, TERRE HAUTE, IN|
Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: July 28, 1998
Publication Date: N/A
Technical Abstract: We have been studying the effect of milk production on periparturient immunosuppresson. Using 6 intact (INT) and 6 mastectomized (MAST) multiparous Jersey cows, we analyzed plasma steroid hormones [estrone (E1), estradiol (E2), progesterone (P), and cortisol (C)] daily feed intake (DMI), plasma calcium (Ca) and nonesterified fatty acids (NEFA), and determined lymphocyte function [interferon-gamma (INF-gamma) and immunoglobulin (Ig)M secretion in vitro] during periparturient period. All INT developed milk fever and 3 INT developed ketosis and displaced abomasum. E1 and E2 showed a marked linear increase from d -10 to d 0 around parturition and dropped rapidly to low levels immediately postpartum. Both E1 and E2 were significantly higher in MAST. P level remained high until 2 d before calving and decreased precipitously prior to calving. C level increased at parturition and decreased to prepartum level on d 2 after calving. Both P and C level showed no significant difference between cow groups. DMI declined before calving and increased after calving in both cow groups. Ca dropped suddenly on the day of calving and NEFA increased significantly from d -1 to d 10 in INT but there was no significant change in MAST. Both INF-gamma and IgM secretion decreased significantly in INT at calving, but not in MAST. The difference between INT and MAST was significant for both lymphocyte assays. Milk production plays an important role in periparturient immunosuppression by diminishing lymphocyte function and recovery in neutrophil function. Significant differences in plasma estrogens, Ca, and NEFA suggest that lower estrogens, hypocalcemia or negative energy balance may contribute to loss of immune function around calving in dairy cows.