Reference | Lefebvre2006 (10034) (Excluded)

Eighty commercial crossbred steers obtained from auction, 9 months of age and weighing an average of 319 kg, were assigned to 1 of 16 pens (5 steers per pen) under controlled feedlot conditions. All cattle were in the same barn and were submitted to the same environmental conditions. Growth promoters used in this project were the ionophore monensin, and the implant Revalor-S. The oxytetracycline antibiotic Liquamycin LA-200 was used. Two pens were allocated to one of eight treatments in a randomized complete block design. The eight treatment combinations imposed after adaptation consisted of 2X2X2 factorial application of control, Rumensin in feed, an injection of oxytetracycline at day 0; the implant Revalor-S at day 0 and again at day 119; and different combinations.

Fecal samples were collected from the rectum of each steer by hand in the morning on days -3, 4, 25, 46, 67, 88, 109, 137 and 165. For colonic tissue collection; at slaughter after evisceration, a sample of colonic tissue of each steer was collected by removing a portion of the distal colon approximately 14 cm above the rectum, using a sanitized knife.

AST Method: Agar Dilution

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: True