Red Blood Cell Phosphate Concentration and Osmotic Resistance During Dietary Phosphate Depletion in Dairy Cows

Journal of Veterinary Internal Medicine

W. Grünberg¹  J.A. Mol² 

[1] Department of Farm Animal Health, Utrecht University, Utrecht, The Netherlands;Department of Clinical Sciences for Companion Animals, Utrecht University, Utrecht, The Netherlands

关键词: Hemolysis;    Hypophosphatemia;    Osmotic resistance;    Postparturient hemoglobinuria;   

DOI  :  10.1111/jvim.12497

来源: Wiley

【 摘 要 】

Abstract

Background

Hypophosphatemia in early lactating dairy cows has been implicated as primary cause for postparturient hemoglobinuria in cattle. Decreased availability of phosphorus has been proposed to reduce adenosine triphosphate synthesis of erythrocytes and thereby reduce osmotic resistance of these cells.

Hypothesis/Objectives

To study the effect of phosphorus depletion on the phosphate concentration ([Pi]) in plasma and erythrocytes and the osmotic resistance of erythrocytes and to determine the association between plasma [Pi] and erythrocyte [Pi].

Animals

Ten healthy midlactating dairy cows in their 3rd to 5th lactation.

Methods

Prospective study. Dietary phosphorus depletion for 5 weeks followed by phosphorus supplementation. Plasma and erythrocyte [Pi] and erythrocyte osmotic resistance were measured. Four cows underwent continuous dextrose infusion at the end of phosphate depletion to exacerbate hypophosphatemia.

Results

Dietary P depletion resulted in a marked decline of the plasma [Pi] from 4.1 ± 1.0 mg/dL to a nadir of 1.7 ± 0,5 mg/dL, but did not alter erythrocyte [Pi] or osmotic resistance. Similarly, dextrose infusion induced a decline of the plasma [Pi] from 2.4 ± 0.5 mg/dL to 1.5 ± 0.5 mg/dL, but had no effect on erythrocyte [Pi] or osmotic resistance.

Conclusions and Clinical Importance

In cattle, marked hypophosphatemia induced by dietary P depletion was neither associated with a decline in erythrocyte [Pi] nor with decreased osmotic resistance of erythrocytes. Phosphorus depletion alone is therefore unlikely to cause intravascular hemolysis and the plasma [Pi] is an unreliable index for the intracellular [Pi] of erythrocytes.

【 授权许可】

Unknown   
Copyright © 2014 by the American College of Veterinary Internal Medicine