The passage of digesta from the abomasum of sheep

Abstract

It is frequently stated that the passage of food through the stomach of the ruminant is a continuous process and this conception is based on the fact that normally food is always found in all parts of the stomach after slaughter, even after a 24 hr. fast. Studies on the rate of disappearance of stained particles from the rumen and their appearance in the faeces can be explained on this assumption while the well-known continuous cycle of contraction ofthe stomach pouches suggests continual mixing and propulsion of food. There is no information, however, on the quantities of food passing from the stomach-whether it stops completely at intervals through the day and night-or on the manner in which the rate of passage is influenced by feeding or rumination. The experiments to be described were undertaken in an attempt to assess the quantity of food leaving the stomach of sheep maintained on constant rations and to study the flow of food residues to the intestines. METHODThe flow of food from the abomasum was measured directly by diverting the flow outside the body through a cannula.Permanent exteriorization of the flow was achieved in one sheep. This method was based on a technique described by Markowitz (1949) for the exteriorization of the flow of digesta along the small intestine of the dog. The duodenum was sectioned approximately 1J in. below the pylorus and the two cut ends were closed by continuous sutures involving the mucosa and submucosal tissues. The closed ends were then inverted and buried by a further continuous suture. An ebonite cannula was inserted into the pyloric part of the abomasum and another into the duodenum. These were exteriorized through stab wounds in the abdominal wall, on either side of the operation wound, so that each cannula was an equal distance from the vertebral coluimn of the sheep. The operation wound was then closed and the two cannulae joined by a glass tube bent at each end to fit the shafts of the two cannulae to which it was joined by rubber tubing.One sheep in which the flow of food from the abomasum to the duodenum was permanently exteriorized was maintained in good condition for 3 weeks after the operation. After this time its * This research was started in the

Digestive secretions and the flow of digesta along the duodenum of the sheep

“…It was noticeable, however, that when the cap was first removed from cannula 1 there was frequently an immediate large 233 234 F. A. HARRISON AND K. J. HILL gush of digesta, which presumably represented drainage from the abomasum. Phillipson (1952) has also mentioned this occurrence and he omitted this material in his estimations of the mean hourly flow.…”

The electromagnetic measurement of the flow of digesta through the duodenum of the goat and the sheep

“…The methods of measurement used by Phillipson (1952) and by Hogan & Phillipson (1960) would prevent the occurrence of retrograde flow, and so might alter the values obtained. Expressing retrograde flow as a percentage of total aboral flow occurring over periods of at least an hour and ignoring the results obtained on goat 48 where artifacts occurred, a mean value of 40 % with a range of 2-56 %, is obtained for retrograde flow in goats, while for the sheep the mean is 5 %, with a range of 0-17 %.…”

“…An assessment of the nutritional importance of microbial activity, which includes both break-down and synthesis of food material, requires as a basic measurement the quantity of material leaving the stomach over a suitable period of time. Phillipson (1952) measured directly the volume of digesta leaving a duodenal cannula. In some of his experiments the duodenum was blocked by an inflated balloon, which reduced the amount of flow; in others, the material flowing out was not returned to the duodenum, and this increased the amount of flow.…”

Effect of duodenal cannulation in sheep on the pattern of gastroduodenal electrical activity and digestive flow

“…Although numerous cannulas have been developed, all of them are basically ' T '-shaped (Phillipson, 1952 ;Weller et a/., 1971) or have a curved barrel (Ash, 1962) and are inserted into the small intestine by conventional surgical procedures (Brown et al, 1968 ;MacRae et al, 1973). Two of these cannulas are necessary in a reentrant system which diverts the flow of digesta to the animal's exterior.…”