Bovine IgG / Passive Immunotransfer (Cow/Calf)

Biology / Background

Calves are born immunologically naive and with virtually no circulating antibodies of their own (agammaglobulinemic). The synepitheliochorial placenta of cattle prevents the transfer of maternal immunoglobulins to the unborn calf. The protection of the newborn calf during the first weeks of life therefore relies exclusively on the intake of immunoglobulins, primarily immunoglobulin G (IgG), from colostrum (first milk).

Pathophysiology / Epidemiology

The absorption of intact immunoglobulins through the intestinal epithelium is possible only during the first few hours of life and declines rapidly with increasing age; with so-called gut closure, this absorptive capacity largely ceases within about 24 hours. If colostrum is ingested too late, in insufficient quantities, or of inadequate quality, or if absorption is impaired, this results in inadequate passive immune transfer (Failure of Passive Transfer, FPT).

Course & Consequences

Failure of passive immune transfer is a major risk factor for the calf’s health. Affected calves are more susceptible to infections and exhibit increased morbidity and mortality rates in the first weeks of life, particularly from diarrhea, septicemia, and respiratory infections; long-term development may also be impaired.

Diagnostic Relevance

The success of passive transfer in calves can be indirectly assessed by measuring the serum immunoglobulin G (IgG) concentration, typically 24 to 48 hours after birth. A serum IgG concentration below approximately 10 g/l (corresponding to a total serum protein level of around 5.2 to 5.5 g/dl) is considered the cutoff value for failure of passive transfer. An early assessment of IgG status allows for targeted corrective measures for individual animals and an evaluation of the farm’s colostrum management.

Rapid Test Component

: The Fassisi® Bovine IgG enables a semi-quantitative assessment of the calf’s immunoglobulin G status using serum or whole blood, thereby supporting the evaluation of passive immune transfer as well as colostrum management within the herd.

References can be found here.