Background: The s placenta is syndesmochorial, which separates the contents of the mother\\\'s blood from the fetus, thereby preventing the transfer of protective immunoglobulins (Ig) from the mother to the fetus. As a result, calves are born without maternal immunity (agammaglobulin). Therefore, the development of maternal immunity in newborn calves is almost completely dependent on the absorption of maternal immunoglobulins in the colostrum3 received at birth. Inadequate intake of colostrum and insufficient absorption of colostrum immunoglobulins by newborn calves in the first hours of life leads to failure of passive transfer immunity. FPT is not a disease, it is a condition that makes newborn calves susceptible to disease and infection. Methods: The failure of passive immune transfer in newborn calves can be evaluated by measuring serum or plasma immunoglobulins (IgG) or total serum protein between 24 hours and 7 days of age. Results: According to the results of the McGuirk and Collins study in the year 2004, in the successful passive transfer of maternal immunity, serum total protein4 (TP) is more than 5.2 g/dL in healthy calves and more than 5.5 g/dL in sick calves. Conclusion: In this research, a herd-based test was used to monitor the passive transfer status in neonatal calves. At least 12 calves aged 1 to 7 per dairy cow herd were tested. In herds that did not have a suitable passive transfer status of maternal immunity, more neonatal diseases such as septicemia, diarrhea, pneumonia, and infectious arthritis were common.

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