Reasons for performing study: The success rate of artificial insemination following the freezing of stallion semen is limited; therefore, improving the stallion semen quality after the freezing and thawing process is a necessary objective.
Objectives: To investigate the influence of glass bead column separation on the freezability of stallion semen.
Hypothesis: Glass beads in a column separator remove damaged and dead spermatozoa in the ejaculate during centrifugation.
Methods: In total, 50 ejaculates from 6 Lipizzaner stallions were studied. Each ejaculate was divided into 2 parts, one half processed following standard procedure and the second half used for the column separation procedure. After freezing, semen quality was evaluated using standard tests for motility, morphology and viability of semen.
Results: Motility and progressive motility of the column-separated (CS) semen were significantly higher (P < 0.001) before freezing and immediately, 24 and 48 h after thawing. A significant increase (P < 0.001) in the percentage of hypoosmotic positive spermatozoa was observed in CS samples. The percentage of total morphological changes in the separated samples before and after freezing was significantly lower (P < 0.001) compared with samples prepared using the standard procedure. A substantial decrease (P < 0.001) was found in the percentage of spermatozoa with damaged acrosomes. However, the percentage of spermatozoa with coiled tails was increased in the separated samples (P < 0.001).
Conclusions: Column separation before freezing has a positive effect on the quality of thawed equine semen.
Potential relevance: The quality of CS frozen/thawed samples indicates their potential use for increasing insemination success in mares.