[The first cleavage of tubal sheep eggs after fertilization with epididymal or ejaculated spermatozoa].

Prealpes ewes (N = 40) were inseminated with mature (ejaculated or epididymal cauda) or immature (epididymal corpus) spermatozoa deposited in the uterine cavity at the time of an induced ovulation (61 hrs. after PMSG injection). Intratubal eggs, recovered and examined either 38 or 48 hrs. later, showed significant differences in segmentation depending on the degree of epididymal maturation of the spermatozoa. Proportion cleaved: 85% of eggs were cleaved after insemination with mature spermatozoa and only 30% after immature spermatozoa were used. Stage of cleavage: 48 hrs. after insemination with mature spermatozoa, 87% eggs were beyond the 4-cell stage, versus 0% after immature spermatozoa.