|ROSENKRANS JR., C|
Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/5/2004
Publication Date: 6/16/2004
Citation: Shroeder, S.B., Edrington, T.S., Looper, M.L., Schultz, C.L., Rosenkrans, Jr., C.F., Flores, R., Callaway, T.R., Anderson, R.C., Nisbet, D.J. 2004. Incidence of foodborne pathogens and antimicrobial susceptibility of fecal coliforms in stocker calves fed ionophore. Proceedings of Western Section of American Society of Animal Science. 55:353-356.
Technical Abstract: Fifty-three cross-bred calves (232 ± 3 kg) were purchased from auction barns to determine: 1) incidence of fecal shedding of E. coli O157:H7 and Salmonella, 2) influence of feeding an ionophore on shedding of E. coli O157:H7 and Salmonella, and 3) antimicrobial resistance of putative fecal coliforms isolated from calves receiving ionophore. Calves were blocked by BW and sex, and assigned in replicate, to receive mineral with ionophore (IONOPH; Lasalocid; 1.76 g/kg mineral) or without ionophore (CONTROL) for 60 d. Calves were fed a corn:wheat midds:soybean meal supplement at 1.5% BW/d. Fecal samples were collected and BW recorded on d 0, 33 and 60. All calves were fed chlorotetracyline in the receiving ration for 10 d and a number of calves in both the control and treated groups were administered florfenicol for respiratory illness during the experiment. Antimicrobial susceptibility of fecal coliforms (n = 11 or 12/treatment) to 14 antibiotics was determined on each collection date. Average daily gain (ADG) was not different (P > 0.10) between ionophore treatment and averaged 0.92 ± 0.07 kg for IONOPH calves and 0.87 ± 0.07 kg/d for CONTROL calves. Sick calves had decreased (P < 0.05) ADG compared with healthy calves (0.78 ± 0.10 vs 1.01 ± 0.06 kg/d). Incidence of E. coli O157:H7 was 1.9% and was not different among treatments (P > 0.10). No Salmonella was isolated from any calf during the experimental period. Patterns of antimicrobial resistance were similar (P = 0.14) between IONOPH and CONTROL calves. Isolates demonstrated the greatest resistance to oxytetracycline, chlorotetracycline, ampicillin and florfenicol (33, 29, 28 and 26% of isolates resistant, respectively). Feeding ionophore to stocker calves had no affect of fecal shedding of foodborne pathogens or on antimicrobial resistance in fecal coliforms.