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

Aitor Fernandez-Novo, Sergio Santos-Lopez, Clara Barrajon-Masa, Patricia Mozas, Eduardo de Mercado, Elisa Caceres, Aizic Garrafa, Juan Vicente Gonzalez-Martin, Natividad Perez-Villalobos, Agustin Oliet, Susana Astiz and Sonia Salome Perez-Garnelo

Department of Veterinary Medicine, School of Biomedical and Health Sciences, Universidad Europea de Madrid, Madrid, Spain; Animal Production Department, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain; National Centre of Selection and Animal Reproduction (CENSYRA) of Colmenar Viejo, Madrid, Spain; Animal Reproduction Department, National Institute of Agronomic Research (INIA), Madrid, Spain; Department of Animal Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain

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.

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Biology 2021, 10(7), 630; https://doi.org/10.3390/biology10070630
Received: 6 June 2021 / Revised: 28 June 2021 / Accepted: 3 July 2021 / Published: 7 July 2021