The effect of duodenal infusion of milk, casein, lactose and fat on gastric emptying and acid secretion in the milk-fed calf.

1. The effect of infusion of the duodenum with milk, casein, lactose and fat on gastric acid secretion and abnormal emptying of a saline meal was studied in milk-fed calves. 2. Compared with sodium bicarbonate, infusion with casein or lactose, alone or together, caused a small but statistically significant slowing of gastric emptying but did not effect gastric acid secretion. 3. Infection of the duodenum with cows' milk replacer or bovine milk fat slowed gastric emptying markedly and reduced gastric acid secretion significantly below levels obtained with sodium bicarbonate infusion. 4. The experiments provide evidence for the existence of mechanisms which prevent the passage of substantial amounts of whole milk into the duodenum before it has been subjected to gastric digestion.