Figure 4. Effect of therapy using a sustained-release ceftiofur formulation on enteric E. coli in the deterministic case considered (r = 0.17, α = 0.05, β = 4⁻³, γ = 0.01; all h⁻¹).

A: Fraction of ceftiofur-resistant among E. coli. B: Total number of E. coli. Dynamics of ceftiofur-sensitive and resistant E. coli in a 6-mos beef treated with C: 6.6 mg CE/kg dosage, and D: 4.4 mg CE/kg dosage. pAMR = frequency of resistance at start of therapy.