Figure 1.

Key events during the developmental ontogeny of the reproductive axis in the ovine fetus. Hypothalamic development and migration of GnRH neurons occur primarily between weeks 5 and 10 of gestation, however, synaptogenesis and neuroplasticity persist throughout gestation and early postnatal life. Pituitary development initiates around day 20 of gestation and LH is detected in the peripheral blood at day 56 of gestation. Primary follicles are present starting on week 17 of gestation while antral follicles develop starting on week 20. This timeline of fetal organogenesis in sheep is developed based on the following references (30, 51, 52, 55, 56). Created with BioRender.com.