Relationships of Follicle Versus Oocyte Maturity to Ultrasound Morphology, Blood Flow, and Hormone Concentrations of the Preovulatory Follicle in Mares1

Abstract

The effects of ultrasound morphology, vascularity, and follicular-fluid hormones of the preovulatory follicle on oocyte recovery rate and on follicle and oocyte maturity rates were studied for 60 spontaneous and solitary preovulatory follicles in mares. An ovulation-inducing dose of hCG was given when the follicle was >or=32 mm (Hour 0), and a procedure for oocyte recovery was done 30 h later (Hour 30). Between Hours 0 and 30, diameter of the follicle increased less and circulating estradiol (E2) concentrations decreased more in groups with successful versus nonsuccessful oocyte recovery and in groups with mature versus immature recovered oocytes, as indicated by significant interactions of group and hour. Significant differences in blood-flow end points between groups were not detected. At Hour 30, the frequency of granulosa serration, an indicator of impending ovulation, was higher (P < 0.001), and the number and expansion of granulosa cells in the lavaging fluid, indicators of follicle maturity, were greater in the oocyte-recovery group and in the oocyte-mature group. Follicular-fluid concentrations of E2, progesterone, and free insulin-like growth factor (IGF) 1 were not different between the oocyte-recovery and -nonrecovery groups. Concentration of progesterone was significantly greater, and E2 and free IGF1 were less in the oocyte-mature than in the immature groups. Results indicated that the post-hCG oocyte-recovery and oocyte-maturity rates were positively affected by follicle maturity. Greater follicular-fluid progesterone and lower E2 and free IGF concentrations were associated temporally with maturation of the oocyte but not with maturation of the follicle.

Relationship of vascular perfusion of the wall of the preovulatory follicle to in vitro fertilisation and embryo development in heifers

“…In summary, greater vascularity of the preovulatory follicle has been associated with greater follicular diameter (women: Bhal et al 1999, mares: Silva et al 2006, heifers: Siddiqui et al 2009b, retrieval rate of oocytes (women: Bhal et al 1999, mares: Ginther et al 2007, retrieval rate of mature oocytes (mares: Ginther et al 2007, Siddiqui et al 2009a, fertilisation rate (women: Bhal et al 1999Bhal et al , 2001) and pregnancy rate (women: Bhal et al 1999, Coulam et al 1999, Huey et al 1999, Du et al 2006, Shrestha et al 2006, mares: Silva et al 2006, heifers: Siddiqui et al 2009b, and lower incidence of triploidy (women: Bhal et al 2001). Studies on the relationship between blood-flow characteristics of the wall of the preovulatory follicle to oocyte retrieval and maturity have been done only in women and mares, and studies on fertilisation and embryo development of the oocyte after IVF have been done only in women.…”

Equine oocyte quality depending on original follicle population

“…We expected to obtain COCs from mature follicles by aspirating preovulatory follicles, 24 hours after administration of hCG (Ginther et al 2007) and COCs from follicles in different stages of atresia by aspirating subordinate follicles at the end of the heat (Watson et al 2002). Also, we were interested in COCs from a greater number of young, viable follicles by aspirating progressive follicle populations before a dominant follicle had developed (Gastal et al 1997, Kanitz et al 2000.…”

Nuclear Configuration, Spindle Morphology and Cytoskeletal Organization of In Vivo Maturing Horse Oocytes

“…The oocytes (n = 37) were obtained from pony mares by transvaginal follicle aspiration during a previous study (Ginther et al. 2007).…”

“…Oocyte maturity is often determined by the presence or absence of the first polar body in the perivitelline space (Choi et al. 2006; Ginther et al. 2007).…”