Differential motility of diploid rabbit spermatozoa.

When rabbit spermatozoa were suspended in a fluid column and incubated for a period of 2.5 hr, there was a change in the relative distribution of morphologically normal, abnormal, and dead spermatozoa. Live, morphologically normal spermatozoa were concentrated in the lower levels of the column, whereas dead and most morphologically abnormal spermatozoa were distributed throughout the upper levels. It appears that the motility of various types of morphologically abnormal rabbit spermatozoa is impaired. These observations strengthen the proposal that the cervix plays an essentially passive role in the selection of spermatozoa during sperm transport in mammals with vaginal insemination.