Semen Quality of the First and Second Ejaculates Collected from Breeding Inactive Stallions after Cooling and Freezing

• Published in: Veterinary sciences 2023-02, Vol.10 (3), p.173
• Main Authors: Podico, Giorgia, Spencer, Kianna M, Magalhaes, Humberto B, Canisso, Igor F
• Format: Article
• Language: English
• Subjects: breeding soundness evaluation; Centrifugation; Cooling; cryopreservation; Freezing; Horses; Membrane potential; Mitochondria; Morphology; Motility; Physiology; Semen; sexual rest; Sperm; Teaching hospitals
• ISSN: 2306-7381; 2306-7381
• DOI: 10.3390/vetsci10030173

This study aimed to assess the semen quality after the cooling and freezing of the first and second ejaculates of the season, which were collected 1 h apart. After collection (n = 40 ejaculates), the gel-free semen volume, concentration, total number of sperm, and sperm morphology were determined. An aliquot of each ejaculate was extended and cooled for 48 h; a second aliquot was cushion-centrifuged and cooled for 48 h; and a third aliquot was processed and then frozen. The total motility (TM) and progressive motility (PM), plasma membrane integrity (PMI), and high mitochondrial membrane potential (HMMP) were assessed pre-(0 h), 24 h, and 48 h post-cooling and before and after freezing. The second ejaculate had a lower gel-free semen volume ( = 0.026). The sperm concentration was greater in the first than in the second ejaculate ( < 0.001). The sperm morphology was similar between the ejaculates ( > 0.05). Cushion-centrifugation prevented a reduction in the TM, PM, and PMI over time ( < 0.05). The TM, PM, and PMI decreased after freezing but not between the ejaculates ( > 0.05). The first and second ejaculates of the season, which were collected 1 h apart, varied in quantity but not in quality after cooling and freezing.