Comparative analysis of microRNAs in bovine colostrum and neonatal calf blood

MicroRNAs (miRNAs) are short non-coding RNAs that participate in a wide range of biological processes. MiRNAs are present in high concentrations in colostrum, and these may be potentially transferred to newborn calves being fed colostrum. The miRNA profile and levels in colostrum and in calf blood before and after colostrum ingestion were analysed in this study.

Two groups of calves, A and B, received colostrum from the same Group A dam twice per day, whereas a third group, C calves, received only 2 L of 'pooled day 0-4' colostrum. MiRNAs from the colostrum and calf blood (before and 24 h after feeding colostrum) were sequenced, analysed, and results validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The number of miRNAs in the calf blood was approximately four-fold higher than in the colostrum. A total of 303 miRNAs were identified in colostrum, of which 296 were known and seven were novel. Whereas 1198 miRNAs (1004 known and 194 novel) were identified in calf blood. Of the miRNAs detected in the calf blood at day 0, 94% were also found at day 1. Of these, 22 miRNAs had significantly different levels between the two time points. However, only miR-1260b was validated to have higher levels in calf blood at day 1 compared to day 0 by RT-qPCR.

As there were minimal differences in the neonatal calf blood miRNA profiles and levels before and after the calves received colostrum, if miRNAs were absorbed into the blood of neonatal calves from the colostrum, that absorption is unlikely to be extensive or ongoing. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.