Reference | Schmidt2020 (29999)

84 steers were blocked by body weight and randomly assigned to two treatments (tylosin or control). Cattle in each treatment were an fed identical diets except for the inclusion of tylosin phosphate in tylosin-treated diets (included at a dose of 60 to 90 mg per head per day). Weight did not differ between groups. Cattle were weighed and samples were collected 4 times: 9 November 2015 (November), 29 January 2016 (January), 25 April 2016 (April), and 20 June 2016 (June). Weight didn’t differ significantly for any of the individual samples collection dates.

Fecal swab, pen surface material, feed, and water trough samples were collected. Fecal swab samples were collected while steers were restrained in a squeeze chute. Samples cultured on selective media, supplemented with 8 mg/L erythromycin, and supplemented with 32 mg/L tetracycline. Samples were tested for Escherichia coli, tetracycline-resistant E. coli, third-generation cephalosporin-resistant E. coli, Enterococcus, tetracycline-resistant Enterococcus, and erythromycin-resistant Enterococcus.

AST Method: None

Reference explicitly reports AST breakpoints: False

Reference reports using a MIC table: False