The quality of colostrum, which is determined primarily by the content of
immunoglobulin G (IgG), is extremely important in order to allow a newborn calf a
sufficient amount of protective components to enable it to obtain immune protection
during the first few weeks of life. There are many methods available to determine the
concentration of IgG in colostrum. In our research we used ELISA test and Brix-scale
refractometer (BRIX%). The objective of the study was to determine the IgG content in
the colotrum of Holstein-Friesian (black and white) dairy cows using these two methods,
to compare the results of both methods and to check the influence of successive milkings
and successive lactations on the IgG content in colostrum. Colostrum samples were
obtained from 29 cows at the first four milkings after calving and frozen until analysis.
All samples were tested with both methods. IgG concentration was significantly lower in
all samples measured by ELISA compared to refractometer analysis. Statistical analysis of
the data revealed that that successive milking has a large effect on the concentration of
IgG in colostrum, while consecutive lactation has no effect. With linear regression model
we found that approximately 6 % of the IgG content variability calculated by BRIX %
was explained by the content determined by ELISA, and 94 % of the IgG content
variability remains unexplained with this model.
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