Abstract
The timing of shedding and disintegration of cytoplasmic droplets from boar and goat spermatozoa was determined. More than 90% of spermatozoa from the cauda epididymidis and ductus deferens had a droplet each at the distal region of the middle piece in both species. In boars, the droplets were still observed in 97% of spermatozoa immediately after ejaculation. After 1 min of ejaculation, however, the percentage of spermatozoa without the droplet greatly increased to 65%, with no significant changes thereafter. Moreover, most of the free droplets shed from spermatozoa had already disappeared after 1 min of ejaculation. In goats, most spermatozoa (90%) had no droplet even immediately after ejaculation, and the rate of free droplets remaining in the semen was 63%. However, within 2 min of ejaculation, the rate of free droplets remaining in the semen dropped to 8%. These results indicate that shedding of cytoplasmic droplets from boar spermatozoa and their disintegration occur within 1 min after ejaculation. They also suggest that droplets are shed from most of goat spermatozoa during their transit through the urethra and/or immediately after ejaculation, and that their disintegration occurs within a few minutes after ejaculation.
