Single radial immunodiffusion analysis for quantitation of colostral immunoglobulin concentration.

Relative accuracy of the single radial immunodiffusion technique to measure immunoglobulin concentrations of colostral preparations (whey, whole, or fat-free) has been assessed. Fresh colostrum samples were analyzed for major constituents. Gammaglobulin as a standard was compared to total immunoglobulin concentration derived from single radial immunodiffusion analysis of colostral preparations with no differences except between standard and whey. Differences were in part from either enhancement or interference of immunoglobulin diffusion by colostral constituents. Removal of casein and fat during whey preparations caused a concentrating effect upon immunoglobulin constituents resulting in exaggerated precipitin rings. Whey has produced unreliable results: therefore, whole colostrum is recommended for single radial immunodiffusion analysis.