Incidence of Colostrum in Raw Milk.

A survey was conducted to determine the colostrum content in raw milk from dairies in Manitoba, Canada. Colostrum was indirectly measured by the determination of bovine immunoglobulin G (IgG) using a radial immunodiffusion assay. The results showed that 360 milk samples, which accounted for 89% of the total tested samples, were contaminated with colostrum. Of these, 320 samples had IgG levels in the range of 1.0 to 1.5 mg/ml, while 38 samples had an IgG content in the range of 1.5 to 2.0 mg/ml. Two milk samples contained IgG in excess of 2 mg/ml.