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Research article2016Peer reviewed

Faecal excretion of total and acid extractable phosphorus in dairy cows fed rations with different levels of phosphorus

Nordqvist, Maria; Spörndly, Rolf; Holtenius, Kjell

Abstract

BACKGROUNDThe phosphorus (P) originating from livestock operations causes eutrophication. Determination of acid extractable P (AEP) in cattle faeces has been proposed as a tool to identify excessive P feeding. The method has not yet been evaluated in controlled studies with cows subjected to individual recording of P intake. Thus the present study focused on investigating the relationship between different P fractions in faeces from cows fed rations with varying P content. The study also investigated whether AEP in faeces could be used to estimate dietary P intake in relation to the P requirement.RESULTSThe results showed that acid extractable P predicted P overfeeding. P fed in excess of requirements was largely excreted as acid extractable P. The unavailable and/or inevitably lost P fractions in the diets were smaller than assumed.CONCLUSIONThis study demonstrates in experimental studies a positive relationship between measured AEP and indirectly calculated regulated P. Any P fed in excess of requirements was largely excreted as AEP. This fraction is thought to be the most mobile P fraction with regard to potential runoff losses. However, the unavailable and/or inevitably lost P fractions in the diets were smaller than assumed. (c) 2015 Society of Chemical Industry

Keywords

dairy cows; diets; faecal excretion; phosphorus

Published in

Journal of the Science of Food and Agriculture
2016, Volume: 96, number: 4, pages: 1386-1389
Publisher: WILEY-BLACKWELL