
The Colostrum Counsel – The Critical Role of Passive Immunity in Calf Health and Development
March 2025
For colostrum to be considered high quality, it must have an IgG concentration greater than 50 g/L (McGuirk and Collins, 2004). A practical, quick, and cost-effective way to measure colostrum quality on the farm is through the use of a refractometer (Bielmann et al., 2010). Instead of directly measuring IgG concentration, the refractometer assesses the total protein content of colostrum, providing results expressed in % Brix.




