Abomasal secretory responses to teasing with food and feeding in the sheep.

1. Secretion of acid and pepsin from abomasal pouches and contractions of the reticulum and rumen were studied in sheep. Observations were made in sheep after being fasted and when they had food available ad libitum.2. The abomasal pouches were of fundic regions alone and also of the fundic region with a rim of antral mucosa.3. The secretion from both types of pouch was continuous, was increased by feeding and decreased by fasting.4. The volume, pepsin concentration and acid concentration of the secretion from fundic pouches increased within 15-30 min of the sheep being teased with food or fed. These responses were observed in sheep which had food available ad libitum or had been fasted.5. Reticulum contractions and the rumen contractions associated with them (A sequences) increased in frequency when sheep with either type of pouch were teased with food or when they ate.6. Consistent associations between rumination and abomasal secretory activity were not established.7. Mixed fundic-antral pouches did not characteristically show responses to teasing with food and sustained secretory responses were delayed by up to 90 min after feeding commenced.8. It is suggested that a cephalic phase of gastric (abomasal) secretion was revealed in the studies on fundic pouches of the abomasum.