A study of functional markers in raw and processed bovine sperm and their potential uses for fertility prediction and process refinement

The extensive assessment of bull’s reproductive potential prior to breeding is highly important and includes examination of general physical soundness, external and internal genitalia and semen quality. Breeding success depends on the efficient use of bulls with high breeding value but simultaneously semen quality imposes restrictions on the use of these bulls in AI. Several techniques have been devised to assess quality of either fresh or frozen-thawed semen. Among a variety of traditional parameters sperm concentration, sperm raw and post-thaw motility and sperm morphology are commonly used for routine semen assessment in the laboratory. In this study, we investigated differences in sperm metabolic activity relative to their motility that may reflect better the fertility of bulls from their non-return rates (NRRs). To investigate the relationship between mid-piece length and fertility of bovine spermatozoa, sperm biometry was performed on ejaculates obtained from 34 bulls representing six breeds: Holstein (yearlings and mature), Friesian, Belgian Blue, Aberdeen Angus, Charolais and Limousin. Significant differences (