Mineral composition and rates of flow of effluent from the distal ileum of liquid‐fed calves

Smith, R. H.

doi:10.1113/jphysiol.1966.sp007882

Cited by 10 publications

(7 citation statements)

References 25 publications

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“…The choice of ionic strength for the solutions added to ileal effluent in the above procedure requires some explanation. The ionic strength of ileal effluent is variable and difficult to derive with any accuracy, but sodium, potassium, chloride and bicarbonate ions provide the biggest contribution, about 0.12-0-14 for effluent after a milk feed (Smith, 1966) and about o.15-0*17 for effluent from ruminating calves (our unpublished observations). T o this must be added a variable contribution from Mg, Ca and inorganic phosphate which can only be deduced by making assumptions.…”

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 79%

“…In ruminating calves, if ultrafilterable Ca, Mg and inorganic phosphate are assumed to be ionic, calculation from the values in Table 2 suggests a contribution to the ionic strength of about 0.03-0.05. These figures would be reduced if any of the ultrafilterable or osmotically active (Smith, 1966) forms of these constituents were not ionic but bearing in mind the probability of a small contribution from other ions (e.g. ammonium) and the reciprocal relationship between Mg and N a + K concentrations in ileal effluent after a milk feed (Smith, 1966), a reasonable estimate puts the ionic strength between about 0.20 and 0.25 for both ruminating and non-ruminating calves.…”

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

“…There is no unequivocal evidence to suggest that Mg is actively transported across the gut wall (discussed by Smith, 1964). For the older milkfed calf, in which the Mg content of the digesta in the small intestine is probably largely ionic (Smith, 1966), the net amount of dietary Mg absorbed is directly related both to dietary intake (Smith, 1959(Smith, ,1962 and to the time available for absorption from the small intestine (Smith, 1963). It seems reasonable to assume, therefore, that, apart from a small effect from the potential difference across the wall of the small intestine, less than about 15 mV, blood positive, in the sheep (Scott, 1965), the concentration of ionic Mg in the digesta at the absorption site within the small intestine is the main factor controlling the amount absorbed in a given time.…”

Section: Binding Of Magnesium and Calcium In The Contents Of The Smalmentioning

confidence: 99%

“…T o this must be added a variable contribution from Mg, Ca and inorganic phosphate which can only be deduced by making assumptions. In milk-fed calves the Ca in ileal contents appears to be mainly bound (Smith, 1966) and the relatively small amount of inorganic phosphate is probably present largely as insoluble calcium phosphates. Mg, on the other hand, is probably largely ionic (Smith, 1966) and, if this is so, calculation shows that Mg and associated anions contribute about O.O~-O-IO to the ionic strength.…”

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

“…In milk-fed calves the Ca in ileal contents appears to be mainly bound (Smith, 1966) and the relatively small amount of inorganic phosphate is probably present largely as insoluble calcium phosphates. Mg, on the other hand, is probably largely ionic (Smith, 1966) and, if this is so, calculation shows that Mg and associated anions contribute about O.O~-O-IO to the ionic strength. In ruminating calves, if ultrafilterable Ca, Mg and inorganic phosphate are assumed to be ionic, calculation from the values in Table 2 suggests a contribution to the ionic strength of about 0.03-0.05.…”

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

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Binding of magnesium and calcium in the contents of the small intestine of the calf

Smith¹,

McAllan²

1966

Br J Nutr

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I . In ileal contents from differently fed ruminating calves, examined under conditions approximating to those obtaining in vivo, 34-74 % of the magnesium and 63-93 % of the calcium were non-ultrafilterable. The binding was shown to be due to at least two processes, one depending on the presence of phosphate, the other not. 2. Considerable non-phosphate binding occurred in samples adjusted in vitro to pH 5.5 and above. The binding material was probably not a single substance but the bound forms of both Mg and Ca were, at least partly, in equilibrium with the soluble forms, and some competition between the two metals occurred. Thus in any one sample the extent of binding for either metal was influenced by the concentration of both. With normal concentrations it was estimated that, in the ileum, about one-third of the Mg and half of the Ca was bound in this way, irrespective of whether pasture or one of a variety of stall diets was given. 3. Samples adjusted to about pH 6.5 and above (in vivo ileum pH was about 7.47.9) showed further precipitation of Ca and Mg to an extent which partly depended on the concentration of inorganic phosphate. Ca precipitation appeared to be mainly controlled by the concentration of Ca and inorganic phosphate but for Mg the precipitation depended also on the presence of factors other than Mg and inorganic phosphate. One such factor found to be present was the ammonium ion, but its practical importance is uncertain. 4. Ileal contents from milk-fed calves showed considerable non-phosphate binding of Ca but not of Mg.

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Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 79%

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

Section: Binding Of Magnesium and Calcium In The Contents Of The Smalmentioning

confidence: 99%

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

Section: Examination Of Calcium Magnesium and Phosphate Distributionmentioning

confidence: 99%

See 3 more Smart Citations

Binding of magnesium and calcium in the contents of the small intestine of the calf

Smith¹,

McAllan²

1966

Br J Nutr

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Digesta flow and mineral absorption in lambs before and after weaning

Dillon¹,

Scott²

1979

J. Agric. Sci.

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Four young lambs fitted with cannulas at the pylorus and at the ileo-caecal junction were used to study the effects of weaning on digesta flow and mineral absorption. Prior to weaning when milk alone was fed the small intestine was the major site for dry matter disappearance and for the absorption of Ca, P, Na and K. Both the small and the large intestine were, however, important sites for Mg absorption at this time.After weaning, when the lambs were fed a concentrate diet, at least two-thirds of the digested dry matter disappeared within the reticulo-rumen. The small intestine, however, still remained the major site for the absorption of Ca, P, Na and K. Most Mg absorption, in contrast, now occurred anterior to the pylorus and it would appear that the move from hindgut to foregut as a site for Mg absorption was directly associated with the introduction of dry feed and the development of fermentative digestion within the reticulo-rumen.Both before and after weaning the faeces was the major route for the excretion of Ca surplus to requirement and the faeces also became increasingly important as a pathway for P and Mg excretion once dry feed was given. The urine, in contrast, was consistently the major pathway for the excretion of Na and K.

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Secretion and absorption of phosphorus in the gastrointestinal tract of sheep fed on four diets

Poppi¹,

Ternouth²

1979

Aust. J. Agric. Res.

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The effects of three phosphorus supplements on the metabolism of phosphorus in the gastrointestinal tract of sheep were examined. One group of sheep was fed on a low phosphorus (P-L) diet and three other groups on diets supplemented with monosodium orthophosphate (P-MSOP), meat and bone meal (P-MBM) or bran (P-ORG). The total phosphorus (TP), ultrafilterable phosphorus (UP) and nucleic acid phosphorus (NP) in the digesta were measured. There was a large net secretion of phosphorus into the rumen and the first quarter of the small intestine, and net absorption from the remainder of the small intestine of all sheep. The relative concentration of phosphorus in the omasum suggested considerable omasal secretion and a subsequent abomasal absorption of phosphorus, but this was considered to be largely an artefact. There were no consistent differences between diets in the net secretion and absorption of TP at sites along the gastrointestinal tract. Sheep fed on the P-L diet secreted more phosphorus per unit of phosphorus intake than sheep on the other diets. Most UP was present in the abomasum and cranial small intestine where the pH was lowest. The concentration of UP fell precipitously in the small intestine, which suggested that this was the major form of phosphorus absorbed and that there was a high degree of complex formation at the higher pH. The concentration of NP was relatively constant, and the lowest NP/TP ratios were found in the cranial small intestine. NP formed in the rumen was mainly degraded in the cranial small intestine. NP represented half the TP in the colon of sheep fed on diet P-L. The results indicate that the form of phosphorus supplement did not influence phosphorus metabolism in the gastrointestinal tract.

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Mineral composition and rates of flow of effluent from the distal ileum of liquid‐fed calves

Cited by 10 publications

References 25 publications

Binding of magnesium and calcium in the contents of the small intestine of the calf

Binding of magnesium and calcium in the contents of the small intestine of the calf

Digesta flow and mineral absorption in lambs before and after weaning

Secretion and absorption of phosphorus in the gastrointestinal tract of sheep fed on four diets

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