Electromagnetic measurements of duodenal digesta flow in cannulated sheep.

Studies of duodenal digesta flow were made in sheep implanted with an electromagnetic flowmeter probe on the ascending and transverse duodenum and in sheep equipped in the ascending duodenum with a 'Y'-type or 'Ash'-type reentrant cannula or with a 'special simple' cannula. The flow of digesta was recorded between one week and 5 months after surgery. Patterns of the digesta flow through the individual systems of cannulation were compared with that of an implanted probe used as a reference. The order of similarity was Ash reentrant cannula less than Y reentrant cannula less than special simple cannula. The rate of digesta flow was similar for the probe, the Ash reentrant cannula with a one-way valve and the special simple cannula, but it was lower for the Y reentrant cannula due to frequent oscillation of the digesta. It was concluded that accurate quantitative electromagnetic measurements of duodenal digesta flow can now be performed in sheep fitted with the Ash-type reentrant cannula equipped with a one-way valve.