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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Greene, L. W. Articles by Webb, K. E. Search for Related Content PubMed PubMed Citation Articles by Greene, L. W. Articles by Webb, K. E., Jr.

Site of Magnesium and Other Macromineral Absorption in Steers Fed High Levels of Potassium¹

Virginia Polytechnic Institute and State University³ , Blacksburg 24061

Abstract

Six Angus x Simmental steers, surgically equipped with abomasal and ileal cannulae, were used during three metabolism trials. Steers were blocked according to weight and were allotted to diree dietary K levels (.6, 2.4 and 4.8% dry basis) for each trial with the restriction that no animal would receive the same level during two successive trials. Each trial consisted of a 5-d transition, a 10-d preliminary period, a 7-d collection of feed, feces and urine and a 6-d sampling of feed, feces and abomasal and ileal fluid. Chromic oxide (.5%) was used as an indicator to measure flow through the digestive tract. Magnesium absorption decreased linearly (P<.05) with increasing level of dietary K. The primary site of Mg absorption was the preintestinal region followed by a net secretion into the small intestine. Preintestinal Mg absorption was decreased 39% when 4.8% K was fed. Serum Mg was lower at high levels of dietary K. Potassium absorption increased linearly when expressed as g/d and curvilinearly when expressed as percentage of intake, with increasing levels of dietary K. When .6% K was fed, the primary site of K absorption was the small intestine, but with the high levels of K, the preintestinal region was also an important site of absorption. The effect of high K level on Mg absorption in steers was similar to that observed previously in sheep.

¹ Supported in part by a grant from John Lee Pratt Animal Nutrition program at Virginia Polytechnic Institute and State Univ., Blacksburg.

² Present address: Dept. of Anim. Sci., Texas A&M Univ., College Station.

³ Dept. of Anim. Sci.

This article has been cited by other articles:

				K. Holtenius, C. Kronqvist, E. Briland, and R. Sporndly Magnesium Absorption by Lactating Dairy Cows on a Grass Silage-Based Diet Supplied with Different Potassium and Magnesium Levels J Dairy Sci, February 1, 2008; 91(2): 743 - 748. [Abstract] [Full Text] [PDF]