Bovine IgG / Passive Immunity Transfer (Cattle/Calves)

Why Calves Need Colostrum

Calves are born immunologically naive and with virtually no circulating antibodies of their own (agammaglobulinemic). The synepitheliochorial placenta of cattle does not allow maternal immunoglobulins to cross over 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).

Insufficient Passive Immune Transfer (FPT)

The absorption of intact immunoglobulins through the intestinal epithelium is possible only during the first few hours of life and declines rapidly with age; with the so-called intestinal closure (gut closure) within about 24 hours, the ability to absorb these substances largely ceases. 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).

Consequences for Health and Development

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

IgG Test in Calves

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 threshold 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.