Protein Degradation in Rumen and Amino Acid Absorption in Small Intestine of Lactating Dairy Cattle Fed Heat-Treated Whole Soybeans

M. O. Stern, K. A. Santos, L. D. Satter

Research output: Contribution to journalArticlepeer-review

151 Scopus citations

Abstract

Four lactating Holstein cows fitted with rumen cannulae and T-type cannulae in proximal duodenum and terminal ileum were used to measure protein degradation in the rumen and amino acid flow and absorption in the small intestine. Soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C provided 50% of the protein in diets that contained 51% grain, 36% corn silage, and 13% alfalfa hay (dry matter). Spot samples of digesta were collected from duodenum and ileum during 96 h, and lanthanum was an indigestible marker to estimate flow and digestibility of nutrients. With diaminopimelic acid as a microbial marker, apparent degradations of dietary crude protein in the rumen were 73, 80, 66, and 60% for diets containing soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C. Because of the extensive degradation of protein with the raw soybean diet, less total amino acids reached the duodenum, and because of decrease of availability, absorption from the small intestine (g/day) was lowest with this diet. Feeding diets containing extruded whole soybeans increased availability of total essential amino acids in the small intestine compared with diets containing soybean meal and whole soybeans. Absorption from the small intestine (g/day and percent entering) of individual amino acids was generally higher for extruded whole soybean diets.

Original languageEnglish (US)
Pages (from-to)45-56
Number of pages12
JournalJournal of Dairy Science
Volume68
Issue number1
DOIs
StatePublished - 1985
Externally publishedYes

Bibliographical note

Funding Information:
Four lactating Holstein cows fitted with rumen cannulae and T-type cannulae in proximal duodenum and terminal ileum were used to measure protein degradation in the rumen and amino acid flow and absorption in the small intestine. Soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C provided 50% of the protein in diets that contained 51% grain, 36% corn silage, and 13% alfalfa hay (dry matter). Spot samples of digesta were collected from duodenum and ileum during 96 h, and lanthanum was an indigestible marker to estimate flow and digestibility of nutrients. With diamino-pimelie acid as a microbial marker, apparent degradations of dietary crude protein in the rumen were 73, 80, 66, and 60% for diets containing soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149°C. Because of the extensive degradation of protein with the raw soybean diet, less total amino acids reached the duodenum, and because of decrease of availability, absorption from the small intestine (g/day) was lowest with this diet. Feeding diets containing extruded whole soybeans increased availabilir_y of total essential Received May 21, 1984. 1R esearch Supported by the College of Agricultural and Life Sciences, University of Wisconsin, Madison, Federal Hatch Project 1891; American Soybean Association, St. Louis, MO; and Triple "F" Feeds, Des Moines, IA. 2Department of Animal Science, University of Minnesota, St. Paul, MN 55108. 3Department de Zootecnia, Escola Agronomica - U.F.B.a. Cruzdas Almas Bahia, Brazil. 4Dairy Forage Research Center, USDA-ARS, University of Wisconsin, Madison 53706.

Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.

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