Currently, adequate passive transfer in calves is most commonly determined by measuring serum immunoglobulin (IgG) or its proxy, total protein (TP).
SUMMARY:
-Tests for failure of passive transfer may underestimate immunity if performed in calves less than 24 hours of age.
-The current cut-off levels for IgG and TP as markers of adequate versus inadequate passive transfer may need to be reconsidered.
-After the first 48 hours of life, and in sick or dehydrated calves, TP may not accurately reflect the immune status of a calf.
-The use of GGT as a measure of passive transfer is no longer recommended.
For more information, read the article below. (First published in VetScript, Oct/Nov 2024)