this study investigated the effect of gnrh analogues on inducing ovulation of dominant follicle (df)and subsequent corpus luteum (cl) lifespan in the presence of norgestomet implant in holstein heifers. onday 6 to 8 of the estrous cycle (day 0 of the experiment), all heifers (n=15) received norgestomet implantfollowed by prostaglandin injection on days 0 and 1. on day 4, group 1 (n=4) and 2 (n=...

Background: Recent studies have revealed that adiponectin, a novel adipocytokine, and its two receptors (AdipoR1 and AdipoR2) are involved in regulation of ovarian function in various farm animal species. The aim of this study was to investigate the gene expression pattern of Adiponectin and its receptors in ovarian cells of dominant (DFs) and non- dominant follicles (NDFs) in the bovine. Mater...

The objective of this study was to investigate the effect of equine chorionic gonadotropin (eCG) on ovarian follicles at three stages of development (emergence, dominance and early static phases) during the first follicular wave (FFW) in Holstein heifers. Heifers (n=20) were randomly assigned into four experimental groups (n=5 in each group). Heifers received eCG (500 IU; Folligon®; Intervet, H...

Central roles in reproductive biology (i.e., growth and development of the oocyte, steroidogenesis, and ovulation) are played by the ovarian dominant follicle (DF). The DF is different from other follicles because it can escape atresia (the fate of all other follicles), and if exposed to the LH surge, its cells will differentiate into the corpus luteum. The DF was originally studied by looking ...

The mechanism by which one or more dominant ovarian follicles continue development while other subordinate follicles regress is not known. The mitogen activated protein kinases (MAPKs) are a group of kinases that are activated by hormonal factors and form a cascade of processes that regulate cell growth, division and differentiation. The aim of the present experiment was to characterise the pre...

The interovulatory intervals of mares contain various combinations of minor follicular waves (largest follicle does not become dominant) and major waves (largest follicle becomes dominant). After emergence of an ovulatory follicular wave, the follicles grow in a common-growth phase until the beginning of deviation. At deviation, the dominant follicle continues to grow and the subordinate follic...

We reviewed recent in vivo studies of the real-time changes in the vasculature of the follicle wall during selection of the dominant follicle as well as during ovulation in cows. Changes in follicle diameter and vascularity were determined by transrectal ultrasonography. Blood flow within the walls of the two largest follicles was detected at the time of wave emergence (largest follicle=5 mm in...

The nature of selection of the dominant follicle is reviewed by comparing research results between cattle and horses. In both species, emergence of a follicular wave is stimulated by an FSH surge. The surge reaches a peak by the time the follicles attain 4 mm in diameter in cattle and 13 mm in mares. In cattle, all of the growing follicles >/=5 mm contribute to the decline in FSH concentrations...