Characterisation of movement pattern and velocities of stallion spermatozoa depending on donor, season and cryopreservation.

The research article examines the different movement patterns and speeds of stallion sperm depending on variables such as the stallion donor, the time of year (breeding vs non-breeding season), and the process of cryopreservation (freezing and thawing). The study concludes that these factors all significantly impact the motility and viability of the sperm.

Study Methodology

• This study was conducted on four different stallions, representing different donors. This helped to determine if the sperm characteristics varied based on the individual stallion.
• Ejaculates were collected in the months of May and December, representing the breeding and non-breeding seasons respectively. This established if the time of year had an impact on sperm movement patterns and velocities.
• A total of 48 ejaculates were collected and analyzed, with 24 collected in May and 24 in December.
• The features of sperm movement, including percentages of motile sperm (sperm that can move effectively), different patterns of motility, velocity, linearity (straightness of movement), amplitude of lateral head displacement (width of the sperm head’s side-to-side movement), and beat-cross frequency (rate at which the sperm tail crosses over its movement path) were analyzed through a computer-aided sperm analysis (CASA) system.

Findings

• Average motility was slightly higher in winter compared to breeding time in May.
• Cryopreservation and thawing had a significantly negative impact on the motility of sperm, reducing the percentages of motile sperm to 11.3% in May and 15.6% in December.
• The process of freezing and thawing also altered the movement patterns of the sperm. There was a shift from linear (straight-line) movement to more non-linear movement, and an increase in the number of locally motile and hyperactivated sperm.
• Average velocity of the sperm differed between May and December, with the sperm moving faster in the colder month of December.
• After cryopreservation and thawing, there was a small increase in the curvilinear (path along a curve) and straight-line velocities of sperm.
• The beat-cross frequency and amplitude of lateral head displacement in stallion sperm were found to be closely correlated with each other.
• The non-breeding season saw a slight reduction in the beat-cross frequency.

Conclusions

• The study concluded that several factors significantly impact the motility of stallion sperm, with cryopreservation having the most significant impact, followed by the individual stallion, and then, the season.