This study identified several novel genes in peripheral blood immune cells (PBMCs and PMNs) of pregnant Bos indicus heifers that are differentially expressed compared to non-pregnant heifers as early as 18 days after insemination. These genes, including interferon-stimulated genes and others not previously associated with pregnancy, could potentially be used as early pregnancy biomarkers in cattle.

The authors declare no competing interests, although the paper received funding from the São Paulo Research Foundation (FAPESP) and received materials (hormones and semen) as donations, which might represent an indirect conflict of interest.

The research is well-designed and executed, identifying novel transcripts associated with early pregnancy in cattle. The methodology is generally sound, using RNAseq and qPCR to analyze gene expression in immune cells. The study's findings are promising for developing earlier pregnancy diagnostic tools in cattle. However, the small sample size and breed-specific focus are limitations that warrant further investigation. The disclosed lack of mechanistic insights and validation of the diagnostic potential also prevent a higher rating. There is a potential indirect conflict of interest due to donations and funding that could slightly bias the study's outcomes.