Differential effect of acid meals on abomasal emptying and secretion in the milk-fed calf.

Preruminant (milk-fed) calves were prepared with an abomasal and re-entrant duodenal cannulae to assess the effect of acid test meals on abomasal emptying and secretion. Isotonic saline meals acidified with hydrochloric acid to pH 2 instilled directly into the abomasum did not affect abomasal emptying or acid and pepsin secretion when compared with saline meals at pH 6. Isotonic saline meals at pH 1.2 significantly inhibited abomasal acid secretion, but had little effect on emptying or pepsinogen secretion. Abomasal emptying, acid secretion and pepsinogen secretion were significantly inhibited when acid was introduced into the duodenum, irrespective of the acidity of the test meal. It is concluded that in the calf acid meals inhibit gastric acid secretion alone without effect on pepsinogen secretion and abomasal emptying. All three abomasal functions, however, were inhibited by acidification of the duodenum.