Development of digestive functions in the newborn ruminant.

To assess the progress of developing digestive functions accurately, it is necessary to evaluate the relative changes of certain variables. Observations have been reported on anatomical, biochemical and physiological changes that occur during the digestive adaptation of the neonatal lamb or calf to the extra-uterine life. For example, chymosin, a milk-clotting acid protease, is maintained by the milk diet at a high level until weaning in calves, as a result of the stimulation by casein of the rate of chymosin synthesis.