Rate of establishment of a fertilising population of spermatozoa in the sheep cervix after a single mating at the onset of oestrus

Abstract

In order to study how soon a population of spermatozoa capable of fertilisation could progress into the cervical canal, the vaginal contents were flushed with a detergent solution at different intervals after mating at the onset of oestrus. Eggs recovered 1 or 2 days later from the oviducts were stained and examined by phase-contrast microscopy. Flushing at 3 minutes after mating did not prevent fertilisation in 44% of instances, whereas similar flushes performed at 6 or 9 minutes completely prevented fertilisation in a total of 26 animals. In the groups flushed at 12 and 15 minutes, the proportion of eggs fertilised was 21% and 24%, respectively, and this increased to 37% after flushing at 18 minutes. An explanation is offered for the paradoxical finding at 3 minutes, and it is concluded that at least 30-60 minutes would be required for adequate colonisation of the cervix with a fertilising population of spermatozoa under the conditions employed in the experiment. However, multiple matings or mating closer to the time of ovulation might act to reduce this interval.

Factors Influencing Sperm Migration in the Fallopian Tubes

“…Some 10-12 hours after mating are required for sufficient spermatozoa to have entered the tubes to ensure subsequent fertilisation of most eggs (Hunter et al 1980;Wilmut 1982, 1984). Much of this interval may be needed for passage of an adequate number of viable spermatozoa across the cervical barrier (Hunter and Nichol 1993). However, as first suspected by Du Mesnil du Buisson and Dauzier (1 955) and demonstrated by in sheep, passage of spermatozoa to the Fallopian tubes is both accelerated and numerically enhanced by mating close to the time of ovulation.…”

Current Knowledge on the Transport and Fate of Spermatozoa in the Reproductive Tract of the Bitch

“…The transport and survival of spermatozoa within the female reproductive tract have been studied extensively in humans (Drobnis and Overstreet ) and other species including cattle (Hunter ; Suarez et al. ), sheep (Hunter and Nichol ), pigs (Mburu et al. , ) and horses (Dobrinski et al.…”

“…The transport and survival of spermatozoa within the female reproductive tract have been studied extensively in humans (Drobnis and Overstreet 1992) and other species including cattle (Hunter 1995;Suarez et al 1997), sheep (Hunter and Nichol 1993), pigs (Mburu et al 1996(Mburu et al , 1997 and horses (Dobrinski et al 1995(Dobrinski et al , 1996. In dogs, studies on the distribution and survival of spermatozoa in the female reproductive tract are more limited but interesting new insights have recently been recognized.…”