Figure 2.

Relative abundance of TC-r genes in fresh excrements from dairy cows (A), heifers and their calves (B–D). TC-r gene abundances were normalized to rrs gene copies and expressed on a log-scale (means and standard deviations are shown on bars and error bars). Dairy cows (n = 5) were sampled at 0, 1, 2, 3, and 8 days after Metricycline suppository administration (A). Heifers (n = 6) were sampled at 4 months before the first delivery and at 0, 2, and 8 days after the first Metricycline suppository administration (corresponding respectively to H-t0, H-t1, H-t2, and H-t3 in B–D). Calves (n = 6) were sampled at 1–2 weeks and at 1–2 months after birth (corresponding respectively to C-t1 and C-t2). Lower case letters above the error bars indicate statistical differences between time points (P < 0.05).