Quantitation of α-linked Glucose Polymers Passing to the Small Intestine in Cattle

The amount of a-glucose polymers entering the duodenum of re-entrant cannulated steers was measured. In each of two trials, four steers received 275 g or 500 g of a high-grain diet every 2 h; 16 and 12 total duodena/ digesta, 8-h collections were made. The mean flows of digesta were 976 and 1,685 ml/h, and dry matters of duodenal digesta were 4.8 and 5.8% when animals were given 275 and 500 g of feed. About 58 to 60% of consumed dry matter was digested and absorbed before reaching the duodenum at both intakes. Glucose in duodenal digesta, as a percentage of that ingested, was 3.6 and 5.2, and total glucose recovered in duodenal digesta per 8-h collection averaged 20 and 40 g during low and high feed consumption. If all the glucose (60 g/day) passing to the duodenum during 275 g feed intake were absorbed, it would contribute only 9% of the total glucose metabolized by these animals.