Pregnancy rates after artificial insemination with cooled stallion spermatozoa either with or without single layer centrifugation.

The research investigates the impact of single layer centrifugation (SLC) in artificial insemination using cooled stallion sperm samples. The study finds out that SLC-selected sperm samples, even from stallions without known fertility problems, exhibit higher pregnancy rates following artificial insemination compared to uncentrifuged controls.

Research Objectives

• The main aim of this study was to find out whether improvements in sperm quality obtained through single layer centrifugation (SLC) result in increased pregnancy rates after artificial insemination.
• The researchers used normal ejaculates from stallions with no known fertility problems for the insemination trials.

Methodology

• The study was conducted in various centres with sperm samples from eight stallions. These samples underwent single layer centrifugation (SLC) for use in artificial insemination.
• Two groups of sperm samples were formed – SLC-selected and uncentrifuged, which were used in the insemination of about 10 mares per treatment group for each stallion.
• After artificial insemination, ultrasound examination was performed about 16 days later to detect the presence of an embryonic vesicle.

Findings

• The researchers found that the pregnancy rate per cycle was higher for the SLC-selected sperm samples at 69% compared to the uncentrifuged control group which was 45%.
• This difference in pregnancy rates was determined to be statistically significant (P < 0.0018), indicating that the difference is not likely due to chance.

Conclusions

• The results confirmed that SLC-selected sperm samples provide an increase in pregnancy rate after artificial insemination.
• The improvement in sperm quality as seen in SLC-selected samples proved beneficial, even when the sperm samples originated from stallions with no known fertility problems.