Concurrent studies on the flow of digesta in the duodenum and of exocrine pancreatic secretion of calves

1. Two surgical techniques were developed in the calf to study the role of pancreatic secretion in digestion. The secretion was collected through a cannula placed in a small sac of duodenum into which the pancreatic duct drained. The continuity of the duodenum was re-established in the first technique by duodenal re-entrant cannulas, and in the second technique by end-to-end anastomosis of the duodenum with a cannula placed cranial to the anastomosis to return the pancreatic secretion. The accessory pancreatic duct was ligated.2. The flows of digesta through the duodenum of milk-fed calves were 5505, 6369 and 7709 ml/12 h at 7, 24 and 63 d of age respectively, similar to values reported previously in the literature. In a 12 h collection period 297, 441 and 602 ml pancreatic fluid were secreted by calves of 7, 24 and 63 d of age respectively. The secretion from the mucosa of the duodenal sac was 40 ml/12 h in two other calves.3. The rate of secretion from the pancreas varied markedly in milk-fed calves, being lowest 2–3 h and highest 6–10 h after feeding. Changes in the concentration of chloride and bicarbonate with pancreatic secretion rate were indicative of a secretin stimulus to secretion.4. The rates of inactivation of pancreatic enzymes collected from the duodenal sac were measured at 4°, 20° and 39°.