title: Effect of feeding a direct-fed microbial on total and antimicrobial-resistant fecal coliform counts in preweaned dairy calves.
abstract: OBJECTIVE
  To determine whether feeding a direct-fed microbial (DFM) to dairy calves would reduce total and antimicrobial-resistant coliform counts in feces and affect average daily gain (ADG).
  
  
  METHODS
  21 preweaned Holstein heifer calves.
  
  
  METHODS
  The study had a randomized complete block design. Within each block, 3 consecutively born calves were randomly assigned to 1 of 3 treatment groups within 24 hours after birth (day 0). Calves were fed the DFM at 1.0 g (DFM1; n = 7) or 0.5 g (DFM2; 7) twice daily or no DFM (control; 7) from days 0 through 29. A fecal sample was collected from each calf daily on days 0 through 3 and then every other day through day 29. Fecal samples were cultured, and mean numbers of total coliforms and coliforms resistant to ampicillin, ceftiofur, and tetracycline were compared among the 3 treatment groups. Calves were weighed on days 0 and 29 to calculate ADG.
  
  
  RESULTS
  Mean total fecal coliform counts did not differ significantly among the 3 treatment groups. Mean ceftiofur-resistant and tetracycline-resistant coliform counts for the control group were significantly lower, compared with those for the DFM1 and DFM2 groups. Mean ADG did not differ significantly between the DFM1 and DFM2 groups; however, the mean ADG for all calves fed the DFM was 0.15 kg less than that for control calves.
  
  
  CONCLUSIONS
  Results suggested that the DFM fed to the preweaned calves of this study did not reduce total or antimicrobial-resistant coliform counts in feces.
authors: Erik M
authors: EM
authors: Corbett
authors: Bo
authors: B
authors: Norby
authors: Lisa W
authors: LW
authors: Halbert
authors: Scott T
authors: ST
authors: Henderson
authors: Daniel L
authors: DL
authors: Grooms
authors: Shannon D
authors: SD
authors: Manning
authors: John B
authors: JB
authors: Kaneene
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001835:Body Weight; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology / Q000517:prevention & control*; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D005260:Female; D019936:Probiotics / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents