Role of Pregastric Esterase in the Abomasal Hydrolysis of Milk Fat in the Young Calf

Abstract

The hydrolysis of milk fat in the abomasum of the calf was studied. Whole milk either was nipple-fed (oral feeding) or was placed directly into the abomasum (abomasal feeding). The latter system was used to minimize the entrance of pregastric esterase into the abomasum. At 1, 2 and 3 hr. after feeding, the contents of the abomasum were sampled and analyzed for total free fatty acids (FFA). The FFA from the oral-fed samples were separated into 3 fractions butyric, valeric and higher fatty acids. The mean concentrations of total FFA ([mu]M/5 g contents) were as follows for the oral and abomasal systems of feeding, respectively: 1 hr., 86, 19; 2 hr., 101, 20; and 3 hr., 120, 30. For the oral-fed samples, the mean concentrations of butyric, valeric, and higher fatty acids were as follows, respectively: 1 hr., 34, 7, 53; 2 hr., 19, 4, 77; and 3 hr., 11, 3, 119.