Effects of Extender Type, Storage Time, and Temperature on Bull Semen Parameters

Abstract

Seminal parameters can be evaluated in situ, or samples can be delivered to a diagnostic centre. How storage conditions affect ejaculates up to evaluation is unclear. We assessed, in 25 commercial bulls electroejaculated in the field, the impact of time until evaluation (0–2 h, 4–6 h, and 24 h post-ejaculation), holding temperature (5 °C vs. room temperature), and extender (AndroMed®, BIOXcell® or INRA96®) on semen quality. Acrosome integrity, sperm viability and morphology, CASA-total and progressive motility, pH, and colony-forming units were assessed. Semen quality was preserved for up to 4–6 h post-ejaculation, except for INRA96® at 5 °C. Regardless of extender or temperature, motility decreased from 4 to 6 h up to 24 h, with the best values obtained with BIOXcell® at 5 °C. pH differed from 4 to 6 h up to 24 h, acidifying when stored at room temperature. Microbiological load was stable over time with AndroMed® and BIOXcell®, and increased at room temperature with INRA96®. Our results suggest that AndroMed® and BIOXcell® can preserve semen quality for up to 6 h, either at 5 °C or room temperature, while INRA96® only at room temperature. These results help to fix adequate protocols for short-term storage and shipment of bovine semen collected under field conditions.

Effect of Extender, Storage Time and Temperature on Kinetic Parameters (CASA) on Bull Semen Samples

“…The total ejaculate volume averaged 6.7 ± 3.83 mL, ranging between 3 and 15.5 mL, and with the following average and deviation values for each quartile of bulls: Q1, 3.25 ± 0.61; Q2, 4.92 ± 0.20; Q3, 6.08 ± 0.38, and Q4, 12.58 ± 3.11. Additional interesting results of the same ejaculates, e.g., proportion of alive/dead spermatozoa, are described in a previous associated article [ 18 ].…”

“…We hypothesized that analyses on semen kept under these conditions beyond 2 h would not estimate adequately the cinematic characteristics of bull semen samples, and that if semen needs to be assessed up to 6 h, it would be better to keep it refrigerated, independently of extender. This work is closely related to another study of our group [ 18 ], in which we assessed the effects of those conditions in semen quality in terms of viability, morphology, total and progressive motility, pH, and microbiological quality.…”

“…This work was carried out concurrently with another study published in the same Journal, as two parts of the same project, using the same ejaculates aliquots [ 18 ]. Therefore, the material and methods were all performed as described in that work.…”

“…In the frame of a broader study of our research group, focusing on semen quality evaluation within the bull breeding soundness evaluation (BBSE) [ 18 ], we observed that conditions of short-term storage of bull semen from collection at the farm until delivery to the laboratory (extender, storage time and temperature) affected semen quality, measured in terms of sperm viability, morphology, motility, pH, and microbiological quality. A deeper analysis of the specific kinetic characteristics will help us to understand the link between these conditions and the semen quality impairment and lead to recommendations for semen storage in the field, to best preserve semen quality.…”

The addition of crocin in the freezing medium extender improves post‐thaw semen quality

“…The observed discrepancies with the last study could be attributed to the different experimental setup. In general, extenders, temperatures, preparation procedures and storage time could affect semen parameters of frozen bovine spermatozoa (Fernandez‐Novo et al., 2021). Constituents of the extender, such as egg yolk, could somehow affect the activity of an antioxidant, thus improving sperm quality (Mata‐Campuzano et al., 2014), while the presence of cryoprotectant agents, such as glycerol, could protect spermatozoa from damage caused by slow freezing (Layek et al., 2016).…”