Comparison of Different Methods to Determine the Absorption of Colostral IgG in Newborn Foals.

The article presents the results of a study examining three methods for measuring the levels of immunoglobulin G (IgG), a type of antibody important for newborn foal health, in newborn foals. The study found that these methods – a commercial SNAP assay, total protein determination, and total globulin determination – performed similarly, with slight variances in sensitivity and specificity.

Research Overview

• The research was carried out to compare the effectiveness of three methods for determining the level of colostral IgG, antibodies from the mother’s initial milk, in newborn foals. This process is critical for the foal’s health and development.
• The methods that were compared include a commercial SNAP assay, total protein concentration determination, and total globulin calculation, and were compared against a reference method, quantitative ELISA (enzyme-linked immunosorbent assay).

Methods and Criteria

• The study involved 119 samples collected from 148 foals aged between 1 to 6 days.
• A blood concentration of 800 mg/dL was considered as a benchmark indicating proper absorption of colostral IgG. Conversely, a concentration lower than 400 mg/dL was considered to indicate hypogammaglobulinemia, a situation where the blood contains below-normal levels of antibodies.

Findings

• The SNAP test showed a sensitivity of 64.5% and specificity of 94.7% in diagnosing sufficient absorption of IgG at a concentration of 800 mg/dL. For concentrations lower than 400 mg/dL, its sensitivity was 89.4% and specificity was 83.0%.
• For total protein concentration, a value of 54 g/L was found most appropriate, with a sensitivity of 67.3% and specificity of 84.2% for proper IgG absorption. For IgG concentrations under 400 mg/dL, the sensitivity was 65.2% and specificity was 76.8% at a value of 51 g/L.
• For total globulin, a value of 27 g/L yielded a sensitivity of 74.5% and specificity of 81.6% at adequate IgG levels. For concentrations under 400 mg/dL, the sensitivity was 75.8% and the specificity was 78.1% at a value of 24 g/L.

Conclusions

• All three methods – the SNAP test, the total protein method, and the total globulin method – performed similarly well compared to the quantitative ELISA in determining IgG concentrations equal to or over 800 mg/dL.
• However, for IgG concentrations below 400 mg/dL, the Snap test and the total globulin method performed similarly well but seemed to be more effective than the total protein approach.