A total of 45 preruminant goats were fed either goat milk or a milk substitute to compare the evolution of taurine and glycine conjugated bile acids and the evolution of the intestinal flora during the first month of life. Samples of hepatic bile were obtained from kids of 1, 7, 14, 21, and 28 days old and conjugated bile acids were measured by high performance liquid chromatography. Bacterial flora were determined in 14 and 28 day old animals. Ours results show that under our experimental conditions tauroconjugated bile acids clearly predominated over the conjugated with glycine. This pattern of preferential tauroconjugation persisted at all ages tested and in both groups studied. On the other hand, it seems that the quality of the protein and fat used in the elaboration of the milk replacer affects the intestinal flora and the postnatal evolution of conjugated bile acids.