Proteomic signatures of cervical mucus associated with fertility in Bali heifers (Bos javanicus): Implications for biomarker-based selection in artificial insemination programs

Background and Aim: ) remains suboptimal, with low conception rates following artificial insemination (AI). Cervical mucus (CM) is a critical factor in sperm transport and fertilization; however, its molecular basis in relation to fertility has not been elucidated in this indigenous breed. This study aimed to characterize the proteomic profile of CM in Bali heifers and to identify protein biomarkers associated with fertility-related mucus quality. Materials and Methods: The study was conducted between February and August 2024 in South Sulawesi, Indonesia. Forty clinically healthy Bali heifers (2-3 years old) were sampled during natural oestrus and divided into good CM (GCM; n = 20) and poor CM (PCM; n = 20) groups using a validated five-parameter biophysical scoring system. CM proteins were extracted and analyzed using one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by liquid chromatography-tandem mass spectrometry. High-confidence protein identification was achieved at