The flow of digesta , dry matter and starch to the duodenurn in sheep given rations containing straw of varying particle size

I . Using shccp fitted with re-entrant cannulas in the proximal duodenum, and which were given a ration containing long straw, a series of three experiments was conducted in which the flow of digcsta to the duodenum was measured and sampled continuously for 3 d. Therc appeared to be no consistent effect of this procedure on total flow of digesta to the duodenum from day to day, indicating that under our conditions a 24 h pattern of flow can bc taken as representative of digesta entering the duodenum. 2. In a further series of four experiments, each lasting 3 d, rations identical in composition to that given in the first series of experiments, but differing in the physical form of the roughage component (chopped or ground), were given to the sheep. There was no consistent effect of altering the particle size of the roughage component of the diet on total daily flow of digesta, or in the dry-matter content of the digesta entering the duodenum. 3. Significantly ( P < 0-01) more starch entered the duodenum per day when the ration included long or chopped straw than when it contained ground straw; all rations contained ground maize. 4. A peak in the flow of digesta, dry matter and starch to the duodenurn occurrcd between 4 and 12 h after feeding the shcep.