Diarrhea and malabsorption in calves associated with therapeutic doses of antibiotics: absorptive and clinical changes.

Of 28 healthy, nondiarrheal, colostrum-fed neonatal calves, 22 developed diarrhea after they were given (orally) for 3 to 5 days maximally recommended doses of chloramphenicol, neomycin, ampicillin, or tetracycline. Ampicillin-, neomycin-, or tetracycline-treated calves had significantly (P less than 0.05) decreased and delayed glucose absorption during oral glucose tolerance tests. Chloramphenicol-treated calves had significantly (P less than 0.05) higher base-line plasma glucose concentrations during the non-test period and had no significant increase in blood glucose concentrations during the tolerance tests compared with those in control calves.