[Kinetics of fecal excretion of Escherichia coli K99+ by calves after experimental infection].

Complete kinetics of fecal excretion of K99+ E. coli in colibacillary diarrhoea of young calves is not known. Six calves received two liters of colostrum as a first meal and UHT sterilized milk later. They were kept in isolators. When one week old, they received orally 2.5 X 10(10) to 9.8 X 10(10) K99+ E. coli which are able to grow on adonitol. These bacteria numbered on a minimal medium with adonitol were excreted at a level between 10(5) to 10(8)/g of feces during about eight days. Calves a few weeks old might be healthy carriers of K99+ E. coli and contaminate newborn calves which are highly sensitive to enterotoxigenic colibacillary diarrhoea.