Malabsorption due to selected oral antibiotics

This article represents an overview of recent research conducted on antibiotic-induced malabsorption in calves. The authors feel strongly that this work identifies a serious and ill-defined problem in the management of neonatal calves. Too often the solution utilized by veterinarian and stockmen for controlling neonatal diarrhea has been to administer oral antibiotics. In many cases, this has been done on the basis of antibiotic sensitivity testing, an approach that seems appropriate. Unfortunately, little consideration has been given to the relative sensitivity of the neonatal intestinal mucosa, with its very rapid turnover, to the potentially detrimental effects of oral antimicrobial therapy. The data that we have collected over the past 3 years conclusively demonstrate that high levels of four commonly used oral antibiotics, especially neomycin and chloramphenicol but also tetracycline and ampicillin, can cause a malabsorption diarrhea in normal calves. This action is not due to viral agents or overgrowth of resistant microbes but is the result of direct modification of the intestinal mucosa. Extrapolation of these data to different dose levels may not be accurate. Oral antibiotics may be of value in treating neonatal enteritis. Conversely, there can be too much of a good thing, and many cases of chronic diarrhea following use of oral antibiotics may be the result of an overenthusiastic and prolonged dosage regimen. Be cautious!