Sperm Viability Assessment in Bovine Fertility

Sperm viability assessment lies at the heart of bovine reproductive management, underpinning the success of artificial insemination and in vitro fertilisation protocols. High viability denotes functional competence, encompassing motility, intact plasma and acrosomal membranes, preserved mitochondrial activity and unfragmented nuclear DNA. Contemporary evaluation bridges classical semen analysis—microscopic appraisal of morphology and motility—with advanced multi-parametric techniques such as flow cytometry, imaging flow cytometry and molecular profiling. These methods enable rapid quantification of viability parameters, integration of metabolic and structural markers, and prognostic modelling of field fertility. Moreover, the optimisation of cryopreservation protocols, diluent composition and thawing procedures remains pivotal for preserving viability during long-term storage. Recent strides in proteomic and transcriptomic profiling, alongside in situ and ex vivo interaction assays, have enriched understanding of how sperm subpopulations contribute to fertilisation potential. The global dairy and beef industries increasingly rely on these insights to refine bull selection, enhance genetic gain and secure sustainable herd productivity.

Research from Nature Portfolio

One foundational study revealed that variations in sperm-borne microRNA profiles, notably miR-216b, directly influence early embryonic cell proliferation. Reduced levels of this microRNA in high-fertility bulls corresponded with elevated expression of the target gene K-RAS in two-cell embryos, leading to improved cleavage rates and blastocyst quality. By linking molecular cargo in spermatozoa to developmental outcomes, this work has established a framework for integrating non-coding RNA analysis into viability assessment and fertility prediction.

Sperm Viability Assessment in Bovine Fertility publication trend

The graph below shows the total number of articles in sperm viability assessment in bovine fertility across all publications each year (not limited to Nature Index journals).

Technical terms

microRNA (miRNA): Small non-coding RNA molecules that regulate gene expression by targeting messenger RNAs.

Flow cytometry: Laser-based technique for quantifying physical and chemical cell characteristics in a fluid stream.

Imaging flow cytometry: Hybrid method combining flow cytometry and high-resolution imaging for detailed analysis of individual cells.

Cryopreservation: Process of freezing cells or tissues at ultra-low temperatures to preserve viability for later use.

Mitochondrial membrane potential: Electrochemical gradient across the mitochondrial membrane indicating sperm metabolic activity.

Acrosome integrity: Status of the enzyme-filled cap on the sperm head, essential for oocyte penetration.

References

1. Sperm-borne miR-216b modulates cell proliferation during early embryo development via K-RAS. Scientific Reports (2019).
2. An ex-vivo assessment of differential sperm transport in the female reproductive tract between high and low fertility bulls. Theriogenology (2022).
3. Identification of sperm proteins as biomarkers of field fertility in Holstein-Friesian bulls used for artificial insemination. Journal of Dairy Science (2022).
4. Systematic review and meta-analysis of cryopreserved bovine sperm assessment: harnessing imaging flow cytometry for multi-parametric analysis. Frontiers in Veterinary Science (2024).