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

Area of Science:

• Animal Science
• Reproductive Biology
• Semen Cryopreservation

Background:

• Semen quality is crucial for artificial insemination success.
• Understanding the impact of ejaculate order and processing on sperm parameters is vital for optimizing cryopreservation protocols.

Purpose of the Study:

• To evaluate the effects of cooling and freezing on the quality of first and second ejaculates collected 1 hour apart.
• To compare the efficacy of different processing methods, including cushion-centrifugation, on preserving semen parameters.

Main Methods:

• Collected and analyzed first and second ejaculates (n=40) for volume, concentration, morphology, total motility (TM), progressive motility (PM), plasma membrane integrity (PMI), and high mitochondrial membrane potential (HMMP).
• Processed ejaculates via extension and cooling, cushion-centrifugation and cooling, or processing for freezing.
• Assessed sperm parameters at 0, 24, and 48 hours post-cooling, and pre- and post-freezing.

Main Results:

• The second ejaculate had a lower volume, but sperm concentration was higher in the first ejaculate.
• Sperm morphology remained consistent between ejaculates.
• Cushion-centrifugation maintained TM, PM, and PMI during cooling, preventing reductions over time.
• While TM, PM, and PMI decreased post-freezing, no significant differences were observed between the ejaculates.

Conclusions:

• Semen quantity differs between the first and second ejaculates, but quality is comparable after cooling and freezing.
• Cushion-centrifugation is an effective method for preserving sperm motility and membrane integrity during cooling.
• Processing method significantly impacts sperm quality preservation, especially during cooling phases.