The measurement of the flow of food to the duodenum of sheep

A comparison of the performance of Scottish Blackface ewe hoggets with and without an exteriorised flow to the duodenum was carried out while the animals were fed on hay with a low nitrogen content and added salt. No evidence was found from the food and water consumed, from the weight changes or from a comparison of the organic matter, nitrogen and ash contents of the food and the faeces that the operation caused any permanent disturbance to digestion. 2. Regular measurements of the flow of abomasal contents to the duodenum established a pattern of flow that was influenced by feeding. A relationship between the quantities passed per hour from the abomasum and the time devoted to rumination was found, but the relationship appeared to be dissociated in time so that increased rumination preceded the increased passage of contents. 3. The mean quantity of abomasal contents passed from four animals was 398 ml./hour. According to the quantities of chromium sesquioxide administered by mouth, passed from the abomasum, and excreted in the faeces this value represents not more than 90% and not less than 86% of the flow that can normally be expected. 4. The quantities of organic matter that disappear in the stomach were calculated and represent about half or more of the total disappearance in the alimentary tract. 5. Substantially more nitrogen left the abomasum than was eaten in the food daily. Of the nitrogen passing to the duodenum the greater part disappeared in the intestines. 6. About twice as much ash left the stomach as was present in the food and about two-thirds of the ash entering the duodenum disappeared in the intestines.