American journal of veterinary research2004; 65(4); 422-430; doi: 10.2460/ajvr.2004.65.422

Validation of diagnostic tests for determination of magnesium status in horses with reduced magnesium intake.

Abstract: To evaluate the diagnostic value of serum concentrations of total magnesium (tMg) and ionized magnesium (iMg), concentrations of magnesium (Mg) in muscle, intracellular Mg (icMg) concentrations, urinary Mg excretion (EMg), Mg clearance (CMg), and fractional clearance of Mg (FCMg) in horses fed diets with Mg content above and below National Research Council recommendations. Methods: 9 young female horses. Methods: 6 horses were fed a reduced-Mg diet for 29 days followed by an Mg-supplemented diet for 24 days. Control horses (n = 3) were fed grass hay exclusively. Blood, urine, and tissue samples were collected, and an Mg retention test was performed before and after restriction and supplementation of Mg intake. Serum tMg, serum iMg, muscle Mg, icMg, and urine Mg concentrations were measured, and 24-hour EMg, CMg, and FCMg were calculated. Results: Reductions in urinary 24-hour EMg, CMg, and FCMg were evident after 13 days of feeding a reduced-Mg diet. Serum tMg and iMg concentrations, muscle Mg content, and results of the Mg retention test were not affected by feeding the Mg-deficient diet. Spot urine sample FCMg accurately reflected FCMg calculated from 6- and 24-hour pooled urine samples. Mean +/- SD FCtMg of horses eating grass hay was 29 +/- 8%, whereas mean FCtMg for horses fed a reduced-Mg diet for 29 days was 6 +/- 3%. Conclusions: The 24-hour EMg was the most sensitive indicator of reduced Mg intake in horses. Spot sample FCMg can be conveniently used to identify horses consuming a diet deficient in Mg.
Publication Date: 2004-04-14 PubMed ID: 15077683DOI: 10.2460/ajvr.2004.65.422Google Scholar: Lookup
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  • Comparative Study
  • Journal Article
  • Research Support
  • Non-U.S. Gov't

Summary

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The article evaluates the effectiveness of various diagnostic tests for identifying magnesium deficiency in horses. The researchers fed some horses a diet with reduced magnesium content, and contrasted their test results with a control group fed on a normal diet. The researchers found the 24-hour urinary magnesium excretion test to be the most sensitive indicator for detecting reduced magnesium intake.

Study Design and Methodology

  • Nine young female horses were chosen for this research.
  • Six out of these nine horses were given a magnesium-deficient diet for a span of 29 days and after that they were put on a magnesium-supplemented diet for a period of 24 days.
  • The rest of the horses (three of them) were used as control samples and were only fed grass hay.
  • The team of researchers collected blood, urine and tissue samples from the horses. They performed a magnesium retention test before and after restricting and supplementing the magnesium intake.

Measurements and Observations

  • Various tests were performed on the collected samples, such as serum total magnesium (tMg), serum ionized magnesium (iMg), muscle magnesium, intracellular magnesium (icMg), and urine magnesium concentration measurements.
  • The researchers made calculations on 24-hour urinary magnesium excretion (EMg), magnesium clearance (CMg), and fractional clearance of magnesium (FCMg).
  • They found that reductions in urinary 24-hour EMg, CMg, and FCMg were evident after 13 days of feeding the horses a magnesium-reduced diet.
  • However, serum tMg and iMg concentrations, muscle magnesium content, and results of the magnesium retention test were not affected by the magnesium-deficient diet.

Conclusions

  • The researchers concluded that the 24-hour urinary magnesium excretion is the most sensitive and precise indicator of reduced magnesium intake in horses.
  • Another findings was that the spot urine sample FCMg seemed to accurately reflect the FCMg calculated from 6- and 24-hour pooled urine samples. This provides a convenient way to identify horses that are consuming a diet deficient in magnesium.

Cite This Article

APA
Stewart AJ, Hardy J, Kohn CW, Toribio RE, Hinchcliff KW, Silver B. (2004). Validation of diagnostic tests for determination of magnesium status in horses with reduced magnesium intake. Am J Vet Res, 65(4), 422-430. https://doi.org/10.2460/ajvr.2004.65.422

Publication

ISSN: 0002-9645
NlmUniqueID: 0375011
Country: United States
Language: English
Volume: 65
Issue: 4
Pages: 422-430

Researcher Affiliations

Stewart, Allison J
  • Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Hardy, Joanne
    Kohn, Catherine W
      Toribio, Ramiro E
        Hinchcliff, Kenneth W
          Silver, Burton

            MeSH Terms

            • Analysis of Variance
            • Animals
            • Epithelial Cells / metabolism
            • Evaluation Studies as Topic
            • Female
            • Food, Fortified
            • Horse Diseases / diagnosis
            • Horses
            • Magnesium / blood
            • Magnesium / pharmacokinetics
            • Magnesium / urine
            • Magnesium Deficiency / diagnosis
            • Magnesium Deficiency / veterinary
            • Mouth Floor / metabolism
            • Nutritional Requirements

            Citations

            This article has been cited 1 times.
            1. Sanmartu00ed J, Armengou L, Troya-Portillo L, Robles-Guirado Ju00c1, Bassols A, Ru00edos J, Jose-Cunilleras E. Plasma-Ionized Magnesium in Hospitalized Horses with Gastrointestinal Disorders and Systemic Inflammatory Response Syndrome.. Animals (Basel) 2022 Jun 7;12(12).
              doi: 10.3390/ani12121479pubmed: 35739816google scholar: lookup