Submitted to: International Virtual Conference on Infectious Diseases of Animals
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 1997
Publication Date: N/A
Technical Abstract: We have previously established that there is a significant decline in several T-cell subset populations and diminished lymphocyte and neutrophil function in periparturient dairy cows. We hypothesized that milk production may be an immunosuppressive factor. To test this hypothesis, we used 6 mastectomized and 6 intact multiparous Jersey cows (all 6 intact cows developed milk fever). Flow cytometry permitted phenotype analysis of peripheral blood mononuclear cells (PBMC) using monoclonal antibodies against T-cell subsets, B-cells, and monocytes. A leukogram was also done to determine absolute numbers of each cell subset. Lymphocyte blastogenesis (LBT) and polymorphonuclear neutrophil iodination (PMN-IOD) were done to assess functional ability of leukocytes. T-cell populations decreased significantly from 27 d before calving until calving in intact cows (CD3 from 51.3 to 42.7%, CD4 from 29.1 to 25.8%, CD8 from 12.4 to 10.0%, and gd T-cell from 7.6 to 4.8%). In intact cows, monocyte numbers increased at parturition (from 19.3 to 31.6% of the PBMC). In mastectomized cows, only the population of CD3 cells was decreased at parturition (from 49.9 to 45.5%).