In recent years, special attention has been paid to proAKAP4, the precursor of A-kinase anchoring protein 4 (AKAP4), which plays a crucial role in the structure and function of the sperm flagellum. This testis-specific protein forms the fibrous sheath and local signal transduction required for proper sperm capacitation and motility. Highly conserved across species, proAKAP4 levels are strongly correlated with fertility and sperm survivability post-thaw. This review summarizes the biological roles of proAKAP4 and its potential as a semen quality biomarker in various mammalian species, including humans, horses, bulls, boars, dogs, rodents and other species. We discuss structural and molecular aspects of proAKAP4 (e.g., prodomain, PKA interactions, phosphorylation sites), as well as its involvement in key signaling pathways controlling sperm movement, such as the cAMP-PKA cascade and calcium signaling. The review also outlines various methods for measuring proAKAP4, such as ELISA, Western blotting and immunocytochemistry. Particular attention is given to commercial assays, which allow rapid and species-specific quantification of proAKAP4, independent of seminal plasma or cryoprotectant presence. Although the data are promising, researchers highlight the need for further validation in larger populations under varying environmental conditions. Nonetheless, current findings suggest that proAKAP4 may emerge as a standard marker in andrological diagnostics and a valuable tool for selecting breeding males and optimizing semen cryopreservation procedures.

Reproductive performance in roe deer can vary with age, body mass, and habitat, but the relationships among these factors remain incompletely understood. We examined ovarian morphometry and reproductive activity in 105 female roe deer harvested in four hunting grounds in central Poland during 2023–2026. Ovarian length, width, circumference, follicle number, and corpora lutea number and area were assessed in relation to female age, habitat type, and pregnancy status based on macroscopic embryo detection. Ovarian length, width, and circumference increased with age, with the main differences occurring between yearlings and older females. Field-harvested females had greater body mass than forest-harvested females, but habitat type, age class, and body mass did not significantly explain variation in follicle number, corpora lutea number, or corpora lutea area among sexually mature females. Embryos were not detected in October or November; they were detected in 8.3% of females in December and 49% in January. These findings indicate that ovarian dimensions increase with age, whereas reproductive traits in sexually mature females show no clear differences between habitat types. The timing of embryo detection should also be considered when assessing pregnancy from reproductive tract examinations.