Submitted to: Great Lakes International Imaging and Flow Cytometry Association
Publication Type: Abstract Only
Publication Acceptance Date: October 13, 2001
Publication Date: N/A
Technical Abstract: Plasma Ca often decreases in dairy cows at parturition. We hypothesized that hypocalcemia affects [Ca**2+]i stores and, therefore, blunts the [Ca**2+]i response for activating stimuli in immune cells. Using blood samples from Jersey cows, [Ca**2+]i stores were estimated by analysis of [Ca**2+]i released after stimulation by pervanadate and ionomycin in the absence of extracellular Ca. [Ca**2+]i was measured by ratiometric analysis of Fluo-4/Fura-Red ratios using flow cytometry. [Ca**2+]i response to stimuli tended to decrease as calving approached, but significantly increased following calving. [Ca**2+]i stores followed a similar pattern, suggesting that the hypocalcemia in periparturient dairy cows may reduce [Ca**2+]i stores of immune cells, reducing their ability to respond to activating stimuli.