HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hinman, D. D. Articles by Johnson, R. R. Search for Related Content PubMed Articles by Hinman, D. D. Articles by Johnson, R. R.

Influence of Processing Methods on Digestion of Sorghum Starch in High Concentrate Beef Cattle Rations¹

Oklahoma State University³, Stillwater 74074

Abstract

High concentrate rations containing sorghum grain were studied to determine the site and extent of starch digestion in ruminants. Sorghum grain processed by dry rolling, micronizing, steam flaking and grinding was fed in a 4 x 4 latin square design to steers fitted with permanent rumen and abomasal cannulas. The digestion of starch in the rumen and the lower digestive tract were determined. No significant differences in the amount of starch digested in the rumen were found between rations. A significantly reduced intestinal digestion and, therefore, a lower total digestion of starch was observed with dry rolled sorghum, suggesting that the raw starch from dry rolled sorghum had a reduced accessibility to enzymatic attack in the small intestine.

The degree of gelatinization was greatest for the micronized and steam flaked sorghum with small differences between the dry rolled and ground sorghum. In vitro dry matter disappearances in 12-hr. fermentations indicated that the micronized and steam flaked sorghums were digested by rumen microorganisms at a faster rate than the non-heat treated sorghums. The differences in in vitro dry matter disappearance were less after a 24-hr digestion, suggesting that the ultimate extent of digestion of raw starch in the rumen approached that of cooked starch. Differences in volatile fatty acid concentrations and molar percentages were small. There was a slight trend for the acetate to propionate ratio to be lower when the heat and pressure treated sorghum rations were fed.

The increased starch digestion noted from heat and pressure treated sorghum grain explains the increased performance of fattening cattle fed these type of rations. Starch digestion was greater for the ground sorghum grain than for the dry rolled sorghum grain indicating that particle size may be an important factor in the rate and/or extent of starch digestion.

¹ Journal Article 2711 of the Agricultural Experiment Station, Oklahoma State University, Stillwater.

² Present address: Agricultural Extension, Court House, El Centro, California 92243.

³ Department of Animal Science and Industry.