Utilisation Des Principaux Éléments Minéraux Du Mais Ensilé Par Le Mouton en Croissance

et al. 2003

-Ruminant phosphorus excretion and metabolism were studied through a database. Faecal endogenous phosphorus is the main pathway of phosphorus excretion and averages 0.85 of total faecal phosphorus. The remaining 0.15 is unabsorbed dietary phosphorus. Faecal endogenous phosphorus is mainly unabsorbed phosphorus, with saliva being the major source, and is correlated to factors influencing saliva secretion (DM intake, physical dietary characteristics and dietary phosphorus content). Another source of faecal endogenous phosphorus is rumen microbial phosphorus that escaped solubilisation during post-rumen digestion. All factors stimulating microbial growth would increase phosphorus uptake by the rumen microbes and consequently the faecal endogenous phosphorus. Understanding the determinants of faecal endogenous phosphorus flow will help to precise the determination of net phosphorus requirements for maintenance. The role of plasma phosphorus in urinary phosphorus loss is discussed.excretion / phosphorus / quantitative aspect / ruminant

Section: Saliva: the Main Origin Of Faecal Phosphorus Excretionmentioning

confidence: 99%

III. Quantitative aspects of phosphorus excretionin ruminants

et al. 2003

“…The constant true absorption coefficient values advocated [26,28] appear to be too low. However, the remaining variations are probably due to feedstuffs or diets [6,29,30], differences in phosphorus digestive availability [31] and also differences among species and physiological state.…”

Section: Dietary Phosphorus Availabilitymentioning

confidence: 99%

“…Even though inorganic phosphates have been intensively studied (from 1957 [38] to 1998 [39]), the results are scarce for forages and concentrates. The authors who studied phosphorus digestive availability of forages have reported values of 0.70 [29], of 0.75 [35] and even 0.80 in lactating cows [40] for corn silage. In contrast, true absorption (alfalfa) for hay phosphorus was found to be only 0.55 [41].…”

Section: Dietary Phosphorus Availabilitymentioning

confidence: 99%

“…Rumen microbes concentrate phosphorus from rumen fluid and from the diet [53] primarily in organic form, as nucleotides [54]. Moreover, since phosphorus requirements for rumen microbes [54] are higher than animal phosphorus requirements [55], care should be taken to meet the microbe requirements [29,56]. To maintain the concentration of inorganic phosphate in the liquid phase of the rumen contents, dietary phosphorus should be quickly converted into inorganic phosphate.…”

Section: Phosphorus Supply To the Rumen Ecosystemmentioning

confidence: 99%

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II. Quantitative aspects of phosphorus absorptionin ruminants

et al. 2003

-Phosphorus absorption in ruminants was analysed from a database described in a previous article. For common values of ingested phosphorus (2.5-5.0 g·kg -1 of DM), 0.73 of dietary phosphorus is absorbed. The remaining variability is probably due to phosphorus quality. Phosphorus absorbed from silage, cereal, cereal by-products and hay differs greatly. The current true absorption coefficient used to calculate daily phosphorus supply is a constant value in the current systems and often it underestimates the true absorption resulting in an excess of phosphorus being supplied in the diets. Adjusting the true absorption coefficient values requires better characterisation of the phosphorus supplied by each feedstuff. Dietary influences (phytate phosphorus, crude fibre, etc.) were investigated but trials assessing the ration effect on phosphorus absorption are lacking. Since rumen microbes have specific phosphorus requirements, particularly for cell-wall degradation, the feedstuff phosphorus availability for the rumen ecosystem is discussed.absorption / availability / phosphorus / quantitative aspect

“…They were fed to lambs for the determination of phosphorus requirements [36] and the availability of phosphorus in corn silage [37] and alfalfa hay [17]. Pure forage diets were administered to grazing calves in a study of phosphorus metabolism [22].…”

Section: Experimental Diets (Tab Iv)mentioning

confidence: 99%

I. A bibliographic database for quantitative analysisof phosphorus flow in ruminants

et al. 2003

-The present study describes a quantitative analysis of phosphorus metabolism in ruminants. The database compiles 100 sources either published (95) or unpublished (5) involving studies on true or apparent phosphorus balances carried out before 1999. The database reports 652 distinct experimental conditions (lines) described with experimental variables (column) involving a total of 2 982 animals: 414 lambs (33 references), 1 078 sheep (37 references), 64 pregnant ewes (3 references), 212 lactating ewes (5 references), 528 calves (20 references), 4 maintenance cows (1 reference), 519 lactating cows (6 references), 42 kids (1 reference) and 121 lactating goats (3 references). The reliability of the database was tested using some general relationships.metabolism / phosphorus / quantitative aspect / ruminant