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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Miller, J. K. Articles by Cragle, R. G. Search for Related Content PubMed PubMed Citation Articles by Miller, J. K. Articles by Cragle, R. G.

Evaluation of Radiocerium as a Nonabsorbed Reference Material for Determining Gastrointestinal Sites of Nutrient Absorption and Excretion in Cattle¹

University of Tennessee Agricultural Research Laboratory, Oak Ridge¹

ABSTRACT

A series of experiments utilizing 38 dairy cattle was conducted to evaluate radiocerium as a nonabsorbed reference material. Dry matter and daily administered Ce¹⁴⁴ were measured throughout the gastrointestinal tracts of animals ranging in age from young calves to mature cows. Daily fecal recovery of Ce¹⁴⁴ from 11 animals fed grain and hay averaged 97% (CV = 19%) of the daily dose after the fourth day. No pattern of diurnal variation in Ce¹⁴⁴ excretion was evident in fecal concentrations during successive 2-hr collections for 90 hr from two cows. The first measurable amounts of radiocerium appeared in fecal samples collected 10 hr after single doses to two cows. Maximum excretion occurred between 20 and 40 hr after dosing. Similar results were obtained with simultaneously administered chromic oxide. Within-animal comparisons of Ce¹⁴⁴ given by capsule with Ce¹⁴⁴ previously mixed in the feed were made for both milk- and grain-fed calves. With grain-fed calves, no differences were detected in gastrointestinal distributions of the two radiocerium isotopes. However, with milk-fed calves, capsules containing Ce¹⁴⁴ went to the rumen, whereas milk containing the Ce¹⁴⁴ was directed to the abomasum. In the digestive tracts contents of 19 animals over 90% of the radiocerium was adsorbed on to undigested residue, as indicated by ultracentrifugation or availability to cation exchange resin.

¹ This manuscript is published with permission of the Director of the University of Tennessee Agricultural Experiment Station, Knoxville.

² Present address: Department of Dairy Science, The Pennsylvania State University, University Park.

³ Operated by the Tennessee Agricultural Experiment Station for the U.S. Atomic Energy Commission under Contract no. AT-40-1-GEN-242.