Metabolite profile as a prime marker of fertility detection in Egyptian dairy buffaloes (Bubalus bubalis).

Buffalo reproductive performance is frequently compromised by postpartum anestrus and repeat breeding, yet the underlying metabolic mechanisms remain largely uncharacterized. This study aimed to identify serum metabolomic differences among four reproductive status groups, smooth inactive ovaries (SIO), repeat breeders (RB), normal cyclic, and pregnant buffalo under thermal-neutral conditions. Twenty-eight adult healthy buffalo cows (4-6 years old, 400-500 kg) were classified by reproductive status using transrectal ultrasonography and rectal palpation. Serum metabolomic analysis revealed distinct profiles among the groups. Infertile buffalo (SIO and RB) exhibited significant disruptions in amino acid, fatty acid, and bile acid metabolism compared to fertile animals. Indole, acetamide, and carbodiimide were relevant to distinguishing the repeat breeder group, while methylmalonic acid and heptadecanoic acid had their changing relevance in the smooth inactive ovaries' groups. Methylamine, phenylalanine, and galactose methyloxyme discriminate the control group. In contrast, propanediol, urea and carbamic acid were abundant in the pregnant group. These findings suggest that metabolic imbalances in specific pathways are associated with reproductive dysfunctions and may serve as biomarkers for fertility assessment. This integrative approach combining physiological classification and metabolomic profiling enhances understanding of fertility-related metabolic alterations and offers potential for improving reproductive management in buffalo.