Types of ovulators

There are majorly animals are grouped under two categories based on their ovulation- Spontaneous ovulators and Induced ovulators.

Spontaneous ovulators

In many species ovulation occurs spontaneously after normal follicle growth during estrus cycle, this is known as Spontaneous ovulators.

Examples of Spontaneous ovulators – cow, goat, mare, sow, primate. i.e. a secretory pattern of estrogen associated with a developing follicle is able to cause a rise in LH release that causes ovulation.

Induced ovulators

Induced ovulators are animals that do not ovulate spontaneously even in association with normal follicle development.

Vaginal stimulation during copulation initiates neuroendocrine reflex that results in ovulation. Estrogen priming of the hypothalamus and anterior pituitary is essential prerequisite for copulation to induce GnRH and LH release leading to ovulation.

Examples of Induced ovulators- Cat, rabbit, ferret, mink and members of Camillidae family.

Ewe	24 hrs	after onset of estrus
Doe	24 – 36 hrs	after onset of estrus
Pig	38 – 42 hrs	after onset of estrus
Mare	1 -2 days	Before the end of estrum
Cat	24 – 36 hrs	Post copulation
Rabbit	10.5 hrs	Post copulation
Cow	12 – 14 hrs	after end of estrus
Dog	Near the beginning of estrus	Fertilization takes place after 4th day