KEY POINTS
Ovulation
1. Ovulatory follicles are selected at the onset of Iuteolysis (large domestic animals).
2. Ovulation is caused by an estrogen-induced preovulatory surge of gonadotropins.
Corpus Luteum
1. The corpus Iuteum secretes progesterone, which is essential for pregnancy.
2. Luteinizing hormone is important for the maintenance of the corpus Iuteum.
3. Regression of the corpus Iuteum in nonpregnant large domestic animals is controlled by uterine secretion of prostaglandin F2tt.
4. Changes in luteal life span in large domestic animals occur because of changes in prostaglandin F2α synthesis by the uterus.
Ovarian Cycles
1. In spontaneously ovulating animals, ovarian cycles have two phases: follicular and luteal; animals that require copulation for ovulation can have only a follicular phase.
2. The luteal phase is modified by copulation in some species.