Induced ovulation (animals)

Induced ovulation, also known as reflex ovulation, is a reproductive process in female animals where the release of an egg (ovum) from the ovary is triggered by an external stimulus during or just prior to mating, rather than occurring spontaneously as part of an estrous cycle. The stimulus is usually coitus or vaginal/cervical stimulation.

In species that undergo induced ovulation, the female's ovaries are not prepared to release an egg until copulation occurs. Sensory nerve fibers in the vagina and cervix are stimulated during mating. This stimulation sends signals to the brain, specifically the hypothalamus, which then releases gonadotropin-releasing hormone (GnRH). GnRH stimulates the pituitary gland to release luteinizing hormone (LH). The surge of LH is the ultimate trigger for ovulation.

This contrasts with spontaneous ovulation, where the female ovulates regularly as part of an estrous or menstrual cycle, irrespective of whether mating occurs.

The benefit of induced ovulation is that the female only ovulates when mating occurs, thereby conserving energy and resources that would otherwise be expended on preparing for a pregnancy that never happens. It also ensures that ovulation is closely timed with insemination, maximizing the likelihood of fertilization.

Induced ovulation is found in a variety of mammalian species, including rabbits, cats, ferrets, camels, llamas, and some rodents and shrews. The degree to which ovulation is strictly induced can vary between species. Some species may exhibit facultative induced ovulation, where they can ovulate spontaneously under certain conditions.