Change in sample to positive ratios of interferon gamma production over time (days).

a Significantly different (P P-values for multiple comparisons.b 95% confidence interval.c Total number of observations.On each day, this change was determined by comparing the use of a stimulant (pokeweed mitogen, PWM; concanavalin A, ConA; interleukin-12 p40 potentiated ConA, ConA+IL-12 p40; or IL-12 p40 alone) versus no stimulation (phosphate buffered saline) for white blood cells unpreserved or preserved with a transport medium (SCSR-T, NonInvasive Technologies) supplemented in whole blood samples from ten healthy cows.