cyclic alterations in animal female tract and in sexual receptivity related to hormone changes. When searching both American (estrous) and British (oestrous) spellings are used in the literature. (More? Menstrual Cycle - Estrous Cycle | Mouse estrous cycle)
Gr. oistros - a strong desire]. The female reproductive cycle of most mammals (not primates). It consists of four stages: proestrus, where the uterine lining begins to thicken; estrus or the "heat" phase of sexual receptivity when ovulation occurs; metestrus, where the corpus luteum forms and secretes hormones to maintain the uterine lining and prevent further ovulation; and diestrus, where if fertilization does not occur, the uterine lining is reabsorbed.
Recurring episodes of sexual receptivity that precede ovulation in most female mammals. They are characterized by rising and falling levels of estrogens and progesterone in the bloodstream. See also estrogens, progesterone.
The period of cyclic physiological and behavior changes in non-primate female mammals that exhibit ESTRUS. The estrous cycle generally consists of 4 or 5 distinct periods corresponding to the endocrine status (PROESTRUS, ESTRUS, METESTRUS, DIESTRUS, and ANESTRUS).
The estrous cycle (also oestrous cycle; originally derived from Latin oestrus) refers to the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Humans and great apes undergo a menstrual cycle instead. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases.