ISSUE FOCUS FEED & ADDITIVE MAGAZINE January 2024 31 BIOMARKER OF COLOSTRUM QUALITY In practice, the quality of colostrum is most often indirectly determined by measuring the BRIX value using a refractometer. Such device is typically used by winemakers to estimate the sugar content in grapes, must or wine, but can also be used to estimate colostrum quality. Through the refraction of light, a BRIX refractometer gives an indication of the dry matter content in colostrum, which is highly correlated with the IgG content of colostrum as well. The higher the level of dry matter, the higher the antibodies and the better colostrum quality. A clear correlation was observed between colostral IgG content and BRIX in our experiments (Figure 1). This confirms that BRIX could be used as a cheap and useful biomarker to identify the truly interesting immunoglobulins in colostrum. BOOSTING IMMUNOGLOBULINS IN COLOSTRUM Results for farm 1 are shown in Table 1. Significant differences were observed between the control and the treatment period for both BRIX values and IgG concentrations as measured in first colostrum. These differences cannot be explained by a dilution effect of colostrum, as colostrum volumes were not differing. Total amounts of IgG (colostrum volume x IgG concentration) show numerically higher values. Although colostrum volumes and total IgG amounts should be interpreted with caution because the exact time of colostrum collection can differ between cows, the substantial increase in IgG upon supplementing MCFA in the dry cow’s diet was striking. Categorizing cows based on BRIX of first colostrum in low, medium, good, and high quality (Figure 2), further illustrated the positive effect of ABC on colostrum quality. Similar results were observed on farm 2 (Table 2), confirming earlier observations. Again, significant differences were observed between the control and ABC for both BRIX values and IgG concentrations. This time, total amounts of IgG were higher as well. Figure 1. BRIX acts as biomarker of immunoglobulin G content in bovine colostrum Unit Control Parameter Aromabiotic Cattle Standard error P-value BRIX IgG concentration Colostrum IgG amount °Bx mg/ml L g 21.4 49.2 6.97 338 24.1 74.1 6.48 455 0.81 5.58 1.09 64.5 0.014 0.001 0.746 0.196 Table 1. IgG and BRIX in first colostrum increased when supplementing Aromabiotic® Cattle in the maternal dry cow diet (farm 1)
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