Reference | Agga_2016_AppandEnvMic (10226) (Excluded)

Three hundred weaned calves (150 steers and 150 heifers, born between 3 August 2014 and 30 September 2014) from the U.S. Meat Animal Research Center (USMARC) cow-calf production system were used for this trial.150 calves (5 pens with 30 calves/pen) received CTC-medicated feed (Aureomycin, chlortetracycline complex equivalent to 10 mg/lb of body weight/day of chlortetracycline; Zoetis, Kalamazoo, MI) (CTC group) for five consecutive days (last CTC-medicated feed was distributed on 18 February 2015). The remaining 150 calves were used as a control (5 pens with 30 calves/pen) and received feed without CTC throughout the experiment (control group).

Fecal swabs, pen surface material, feed, and water samples were collected on five occasions: at feedlot arrival (arrival, 9 February 2015), 5 days posttreatment (5 dpt, 23 February 2015), 27 days posttreatment (27 dpt, 17 March 2015), 75 days posttreatment (75 dpt, 4 May 2015), and 117 days posttreatment (117 dpt, 15 June 2015). Fecal swabs were collected directly from the rectum using a foam-tipped swab (VWR International, Buffalo Grove, IL).

AST Method: Selective Media

Reference explicitly reports AST breakpoints: False

Reference reports using a MIC table: False