The seminiferous epithelial cycle and spermat ogenesis in rams (ovis aries )

The efficiency of spermatogenesis and degenerations of different spermatogenic cells under normal conditions of the environment have been investigated in rams. The meiotic divisions and the position of first-generation spermatids in haematoxylin-eosin stained testicular preparations were used to identify eight stages of the seminiferous epithelial cycle (SEC). The stages of relatively long duration (i.e., 1,2,3,4,8) were sub-divided. The percent-ages of frequency for the 14 stages reported were also studied. Three generations of type A (A(1), A(2), A(3)), one generation of type intermediate (In) and two generations of type B (B(1), B(2)) spermatogonia were recognized. A(2) and B(2) spermatogonia as well as primary and secondary spermatocytes did not degenerate. Contrarily, A(1), A(2), A(3), In and B(1) spermatogonia showed 25, 13.7, 27.3 and 21.2% degenerations respectively. We concluded that compared with the previously used eight-stage classification, subdividing stages with long durations as done in this study facilitates investigating the degenerations of spermatogenic cells. The efficiency of spermatogenesis in rams was 47.58% since one A(3) spermatogonium produces 30.45 spermatids/spermatozoa against the expected number of 64.