A total of 45 preruminant goats were fed either goat milk or a milk substitute. The postnatal development of bile secretion and biliary lipids composition of suckling goats and the influence upon these parameters of maternal milk substitution were studied during the first month of life. Samples of hepatic and gallbladder bile were obtained from kids of 1, 7, 14, 21 and 28 day-old. Bile flow rate, cholesterol, total bile salts and phospholipids were measured. Our results show that the quality of the protein and fat used in the elaboration of the milk replacer, affects the evolution of both hepatic bile flow and biliary lipids composition. Differences between gallbladder and hepatic bile composition show a scarce concentration capacity of the gallbladder with both diets and at all ages studied.