Intraovarian spatial and vascular harmony between follicles and corpus luteum in monovulatory heifers, mares, and women.

Heifers have two or three major follicular waves per interovulatory interval (IOI). In mares and women, the ovulatory wave is the only major wave in most (75%) IOI. The beginning of diameter deviation during follicle selection of the future dominant follicle (DF) is followed by continued growth of DF and decreasing growth of the future subordinate follicles. Diameter deviation in Bos taurus heifers, mares, and women begins when the future DF is a mean of 8.5, 22.5, and 10.5 mm, respectively. Selection of the ovulatory follicle occurs more frequently from right ovary (RO) in heifers and women and from left ovary (LO) in nulliparous mares with no difference between ovaries in parous mares. The RO predilection for ovulation is preceded by a predilection for more follicles in RO before the beginning of deviation as indicated by (1) in heifers and women, there were more predeviation follicles in RO than LO and ovulation occurred more frequently from RO whereas in mares there was no difference between ovaries in number of predeviation follicles and ovulation occurred with similar frequency between ovaries and (2) in heifers, the number of ovulatory waves with DF in the ovary that had more predeviation follicles was greater than the number of waves with DF in the ovary that had fewer follicles. In heifers, ovulation from RO occurs more frequently when the regressed CL is also in RO and is attributable to a positive intraovarian effect of the CL on predeviation follicles that were adjacent to the CL. The positive two-way effect between CL and future DF when adjacent is expressed by greater dimensions and vascular perfusion of CL and DF. This phenomenon awaits study in mares and women. An exception to more frequent RO ovulation in heifers occurs in wave 3 owing to a switch during predeviation in future dominance to a smaller follicle when the largest follicle is adjacent to the regressing CL. A preovulatory contralateral relationship (DF and CL in opposite ovaries) during the last wave of an IOI in heifers usually (eg, 88%) converts to an ipsilateral relationship during wave 1 of the next IOI in association with continuity in vascular perfusion and number of predeviation follicles per ovary. Alternating relationships between consecutive ovulations were not found in mares and is controversial in women. Applied potential of ovarian asymmetry is indicated by greater blastocyst rate for RO oocytes in cattle and greater pregnancy rate for RO ovulation in women.