Table 1. Calves acquire cef^R E. coli from bedding.

Days	Bedding cfu/g	Feces cfu/g
0	9.6	None
2	5.9	5±0.5
4	4.6	5.4±0.4
7	4.1	6.2±0.2

The log₁₀ cfu (colony forming units) of E. coli strain AR060302 per g of bedding material and feces (n = 2 calves; ± s.e.m). The AR060302 E. coli population declined >5 log₁₀ cfu/g in bedding material while increasing from below detectable level to >6 log₁₀ cfu/g feces (mean ± s.e.m). No antibiotics were administered during the course of this experiment.