Factors regulating the process of ovulation in cattle have received little attention, although a substantial body of information has accummulated in rodent models.This review outlines the current state of knowledge in rodent models, and extends this to cattle.Ovulation is induced by the preovulatory LH surge, which acts on LH receptors of granulosa cells to cause the release of epidermal growth factor (EGF)-like ligands.These then act on cumulus cells to activate the EGF receptor and downstream signaling that includes expression of prostaglandin-endoperoxide synthase 2 (PTGS2), the secretion of prostaglandins, and subsequently proteases that degrade the follicle wall.These processes are modulated by locally acting factors including angiotensin Ⅱ and intracellular nitric oxide.A deeper understanding of factors affecting ovulation may help devise strategies to reduce the incidence of delayed ovulation or follicular cysts in cattle.