Effect of Time of Insemination on the Distribution of Spermatozoa in the Genital Tract in Ewes

Abstract

Merino ewes were artificially inseminated during either early or late oestrus and were killed 4 or 24 hr after insemination. Insemination during late oestrus resulted in fewer spermatozoa in the cervix, the uterus, and the fallopian tubes and in a lower fertilization rate. Increased resistance of the cervical mucus to penetration by spermatozoa during late oestrus appeared to be responsible for these effects.