title: Refractometry as a measure of the immunoglobulin status of the newborn dairy calf: comparison with the zinc sulfate turbidity test and single radial immunodiffusion.
abstract: Immunoglobulins were quantitated by single radial immunodiffusion in 34 female Holstein-Friesian calves which had been kept with their dams for the first 24 hours of life. The mean immunoglobulin G1 (IgG1) concentration was 1.063 g/dl; IgG2, 0.093 g/dl; IgM, 0.171 g/dl; and IgA, 0.125 g/dl. Both serum total protein as measured by refractometer and zinc sulfate turbidity measured at 498 nm gave good correlations with total protein, which were significant, P less than 0.001. Plasma total protein had a slightly poorer correlation with total immunoglobulins, presumably due to variable fibrinogen content. Plasma total protein gave a better correlation with total immunoglobulins than did any of the immunoglobulin classes individually. Total protein by refractometer underestimated naturally occurring or added immunoglobulins by one-third.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D001798:Blood Proteins / Q000032:analysis; D002417:Cattle / Q000276:immunology*; D005260:Female; D005779:Immunodiffusion; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007136:Immunoglobulins / Q000032:analysis*; D009391:Nephelometry and Turbidimetry; D055095:Optics and Photonics; D010783:Photometry; D013431:Sulfates; D015032:Zinc
chemical_list: D001798:Blood Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D013431:Sulfates; D015032:Zinc