Disappearance of spermatozoa from the ejaculates of geldings.

This study focuses on the impact of castration on the seminal characteristics of geldings, specifically the rate of disappearance of spermatozoa from the ejaculates following the procedure. The results show that spermatozoa levels drastically decrease post-castration, and frequency of ejaculation does not fasten this process.

Objectives, Methodology, and Experiment

• The main objective of this study was to study the changes in seminal characteristics of geldings (castrated male horses) following castration, particularly the disappearance rate of spermatozoa (male reproductive cells) from ejaculates.
• The researchers also aimed to observe how the frequency of ejaculation influences these seminal characteristics after castration.
• Two experiments were performed. In the first experiment, semen was collected from eight geldings every other day after castration until the number of sperm cells dropped to less than 1% of the pre-castration amount. An average of three ejaculations were required to bring the sperm count below this threshold.
• The second experiment entailed 15 stallions, which were castrated and divided into three groups for seminal collection at intervals of 7, 14, or 21 days post-castration.
• The results were consistent across both these experiments.

Results and Conclusion

• The results following the experiments showed a significant decrease in the number of spermatozoa in ejaculates post-castration.
• At intervals of 7, 14, and 21 days post-castration, the spermatozoa count averaged 23 million, 14 million, and 2 million per ejaculate, respectively. This showcases a notable drop in spermatozoa count over time.
• Interestingly, the speed of ejaculation did not hasten the disappearance of spermatozoa from ejaculates.
• All sperm cells in ejaculates collected a week after castration were found to be non-motile, i.e., they were not capable of movement or swimming which is essential for fertilizing female gametes.
• The study concludes that it may take several months post-castration before horse’s reproductive structures like the ampulla and vas deferens will be devoid of spermatozoa, making the ejaculates azoospermic (having no measurable level of sperm in semen).
• Furthermore, the study implies that the chances of a successful pregnancy resulting from mating or insemination could be improbable as early as a week after castration.