Providing calves good quality colostrum is important to give them a head start in life. Since there is limited transfer of immunoglobulins (Ig) during gestation, the delivery of the most dominant form IgG through colostrum from the cow to the calf is essential in the first day of life. At Agrimprove, we believe that the dry period is key and offers an interesting window to boost calf immunity.

Improving colostrum quality

Generally, 50 g/L IgG is accepted as a threshold for good quality bovine colostrum (Quigley et al., 2013). These values are often not reached in practice, putting limits on the chances of successful calf rearing. Strategies to improve colostrum quality and increase IgG concentrations have been widely investigated. The dry period is of particularly interest to improve the quality of colostrum. This is the ideal moment to intervene via the diet of the calf’s mother, for example by supplementing medium-chain fatty acids (MCFA). Besides the positive effects of MCFA on modulating rumen fermentation, impacting the immune system and ultimately improving milk quality during lactation, MCFA could as well improve colostrum quality. Indeed, an improved health status during the dry period could positively impact the quality of the cow’s first milk. In swine, it was shown that the addition of MCFA in the maternal diet improved colostrum quality (Swanson, 2022). More recently, the positive effect of MCFA in C-vita on colostrum quality in swine colostrum was also observed (Crowder & Lannoo, 2023).

Quantify the maternal effect of medium-chain fatty acids

Experiments were designed to quantify the effect of Aromabiotic® Cattle (ABC), a mixture of MCFA, on colostrum IgG levels in dairy cattle under field circumstances. On two dairy farms in Belgium, cows were given a daily supplement of ABC during the dry period. On the first farm, starting at least 2 weeks before calving, an all-in-all-out approach was applied, allowing to compare a first set of control cows without ABC to a subsequent period with ABC during summer season. On the second farm, starting 3 weeks prior to calving, two of these alternating periods were applied, allowing to compare summer and winter season as well. Colostrum was collected from the first milking of 86 dairy cows on farm 1 and 87 cows on farm 2. IgG was analyzed using radial immunodiffusion.

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.

Figure 1: BRIX acts as biomarker of immunoglobulin G content in bovine 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 3), further illustrated the positive effect of ABC on colostrum quality.

Table 1: IgG and BRIX in first colostrum increased when supplementing Aromabiotic® Cattle in the maternal dry cow diet (farm 1)

ParameterUnitControlAromabiotic CattleStandard errorP-value
IgG concentrationmg/ml49.274.15.580.001
IgG amountg33845564.50.196
Figure 2: Percentage of animals in the control and Aromabiotic® Cattle group per quality category of BRIX

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. The effect of MCFA was most pronounced during summer season (Figure 3). IgG and BRIX were significantly higher during the more challenging summer period for the ABC treated cows compared to the control. Indeed, during summer time, colostrum fat and protein content tend to be lower when compared to other seasons. Differences between control and ABC were smaller in winter, but showed similar trends. Altogether, results indicated ABC had a positive effect on colostrum quality, especially when circumstances were more challenging.

Table 2: IgG and BRIX in first colostrum increased when supplementing Aromabiotic® Cattle in the maternal dry cow diet (farm 2)

ParameterUnitControlAromabiotic CattleStandard errorP-value
IgG concentrationmg/ml47.760.83.030.002
IgG amountg53064638.70.027
Figure 3: Aromabiotic® Cattle in the maternal dry cow diet on farm 2 showed largest effects during the most challenging summer period

Impacting calf immunity by MCFA in the mother’s diet

At Agrimprove, we work every day to develop solutions helping farmers to improve the profitability of their farm. Fast and healthy rearing of calves is an essential element for the farmer to obtain commercial success. This study demonstrated the potential of Aromabiotic® Cattle as part of the dry cow diet to improve colostrum quality. Therefore, MCFA in mother’s diet supports calf rearing success.

References are available upon request.

Contact your agrimprove expert

Frederik Gadeyne
Product Developer Cattle