Effects of Age and Diet on the Secretion of Pregastric Esterase in Calves

The effects of age and diet on the quantity of pregastric esterase secreted during the nursing of milk were studied in six Holstein calves. During the first 180 days of life, there was no appreciable change in enzyme secretion. Limited observations on two calves suggest that this trend continues through at least 1 yr. of age. Calves sustained on a diet of hay and grain secreted, when nursing milk, approximately the same quantity of pregastric esterase as did those animals restricted to a diet of milk. The output of enzyme during the actual consumption of hay and grain, however, appeared to be considerably less than that stimulated by the nursing process. There was no correlation between the total volume of saliva secreted and the output of pregastric esterase.