Summary

Step-by-step guide for checking whether calves actually absorbed enough colostrum. Explains “passive transfer” of antibodies and how to measure it by testing a calf’s blood serum total protein (STP) or using a Brix refractometer, including target values and best testing times. Lists common reasons passive transfer fails and outlines basic supplies and procedures for collecting blood and reading results so producers can spot problems early and reduce calf illness and losses.