Nine mature mongrel dogs were used to evaluate a surgical technique for the cannulation of the terminal ileum and used in two experiments to determine the effect of carbohydrate source on starch and dry matter digestion. Dogs (16.2 +/- 2.0 kg body weight; means +/- SD) were fitted with an ileal T-cannula constructed of polyvinyl chloride pipe. The cannula was inserted into the terminal ileum approximately 10 cm proximal to the ileocecal junction and the cannula was exteriorized through a small incision on the right flank. Dogs recovered quickly from surgery (5d). A preliminary study using Cr:EDTA in the food indicated that sampling for 12 h postprandially allowed near complete representation of digesta flow for a meal; peak flow occurred 4-to 8-h postfeeding. Two experiments were performed evaluating the effect of carbohydrate source on ileal starch and dry matter digestibility. Dogs were fed two meals daily with Cr2O3 used as a digesta marker. Diets contained 67% extruded grain (corn, rice, oats or barley) and 33% canned meat supplement on a dry matter basis. Starch digestion was complete (> 98%) within the small intestine and was unaffected by carbohydrate source. In experiment 1, prececal and total tract dry matter digestibilities were higher for rice than corn, and in experiment 2, barley was higher than oats. The ileal T-cannula allows for measurement of small intestinal nutrient disappearance without the confounding effects of colonic microflora. This method may be useful when applied to the study of other nutrients in dogs.

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Procedures are described for study of fiber components of feeds and forages. Fifteen feeds and forages were delignified with sodium chlorite and hydrolyzed with trifluoroacetic acid. The hydrolyzed sugars are derivatized to their corresponding alditol acetates and analyzed on the gas chromatograph.Comparisons between the detergent fiber analysis system and the proposed gas chromatograph system are reported. Electron microscopy was used to evaluate chemical action of neutral detergent, acid detergent, sodium chlorite, ammonium oxalate, and trifluoroacetic acid.

Two predominant rumen cellulolytic bacteria, Ruminococcus flavefaciens C94 and Bacteroides succinogenes S85, were incubated with ground filter paper (Whatman no. 1), cattle manure fiber, wheat straw, Kentucky bluegrass, alfalfa, and corn silage as substrates. Analyses of the initial substrate and the recovered residue after 48 h of static incubation showed that R. flavefaciens C94 was quantitatively more effective than B. succinogenes S85 in degrading total dry matter (32.3% versus 16.1%). However, B. succinogenes S85 demonstrated a qualitative advantage in degrading the hemicellulose and hemicellulosic sugars of particular substrates. R. flavefaciens degraded a mean 29.7% of the cellulose and 35.6% of the hemicellulose in the various substrates, whereas B. succinogenes degraded a mean 17.9 and 31.6% of these fractions, respectively. Gas-liquid chromatography was an important aid in characterizing the polysaccharide-degrading capabilities of these rumen species.

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