Calf Fitness Associates with Early Embryo and Recipient Metabolomes and with Calf Epigenetic Marks

We used metadata to explore the metabolic interplay between culture medium from in vitro-produced bovine embryos transferred fresh or frozen, recipient blood plasma, and calf fitness, alongside gene expression and methylation in calf lymphocytes. Principal component (PC) analysis (PCA) identified covariates that were depicted in Debiased Sparse Partial Correlation networks and analyzed as enriched pathways. Four PCs explained 13.77, 9.58, 7.73 and 5.84% variability. PC1 clustered only mother weight and two embryonic metabolites. PC2, PC3 and PC4 associated 10, 17, and 5 calf features with 10, 6, and 16 embryonic and 2, 20, and 5 recipient metabolites, respectively. Subsequently, gene methylation and expression, and calf fitness were analyzed by PCA. Three PCs covered 100% variability. PC1 associated acid-base balance, protein metabolism, Cl^-, and Ca²⁺ with IGF2 and IL1R1 expression, and IL4 and IL12B methylation. PC2 linked H19 expression and methylation with growth and biochemical traits. PC3 clustered growth, hydration, and redox balance, with IGF2, IGF2R, IL1R1 and IL3 methylation, and H19, IGF2, IGF2R and IL12B expression. Gene methylation connected with embryo metabolites through networks via K⁺, Cl^-, HCO₃^- and TCO₂. Calf fitness parallels the early metabolic fingerprints of the embryo and recipient, allowing embryo transfer decision-making based on calf health.