Previous data (Kniffen et al.,
1989; Nielsen and Gyrd-Hansen, 1996) and our current
analysis indicate that the half-life for tetracycline in
swine ranges from 4.5 to 6 h. Therefore, steady state
should be reached between 20 and 30 h; and the first
time point after steady state was reached, 32 h, was
used as a conservative initial time for steady-state PK
analysis.