Figure 1. Ceftiofur metabolites remain biologically available in topsoil under different conditions.

Effect of temperature and addition of cattle feces (1∶25) on ceftiofur metabolites (CFM) as measured by recovery of growth for E. coli K-12 (D₅₀). Main effects and interactions were significant (P<0.0001; two-factor ANOVA). Letters designate group differences based on Tukey-Kramer multiple comparison test (P<0.001). Bars = s.e.m.