Estrus cycle in dogs. the recurrent, restricted period of sexual receptivity in female mammals other than human females, marked by intense sexual urge. The estrus cycle is defined as the phenomenon of cyclic ovarian function in mammals, regulated by the interplay of the hypothalamus, anterior pituitary, and ovaries, leading to follicular maturation, steroid hormone production, and ovulation. Dec 5, 2025 · The estrous cycle is typically divided into four main stages: proestrus, estrus, metestrus, and diestrus. Estrus, the period in the sexual cycle of female mammals, except the higher primates, during which they are in heat—i. , adj es´trual, es´trous. Estrus or oestrus refers to the phase when the female is sexually receptive (" in heat " in American English, or " on heat " in British English). Estrus, commonly known as the 'heat' period, is a distinct phase in the estrous cycle of most female non-primate mammals. Jul 25, 2001 · The period of cyclic physiological and behavior changes in non-primate female mammals that exhibit ESTRUS. . After mating, LH surge induced, progesterone increases then decreases, estrus returns after parturition when progesterone goes back down. This phase is characterized by a complex interplay of physiological and behavioral changes that signal readiness for copulation. It is characterised by a period of intense sexual receptivity, during which the female is willing to accept the male for mating. Estrus or oestrus refers to the phase when the female is sexually receptive (" in heat " in American English, or " on heat " in British English). Estrus, derived from the Greek word "oistros," refers to a period in the reproductive cycle of female mammals when they are receptive to mating. One or more periods of estrus may occur during the breeding season of a species. , ready to accept a male and to mate. The female will only allow the male to mate during a restricted time coinciding with ovulation. See also estrous cycle. Under regulation by gonadotropic hormones, ovarian follicles mature and estrogen secretions exert their biggest influence. The estrous cycle generally consists of 4 or 5 distinct periods corresponding to the endocrine status (PROESTRUS; ESTRUS; METESTRUS; DIESTRUS; and ANESTRUS). The majority of mammals become sexually-receptive (express estrus) and ovulate spontaneously at defined intervals. Some species also experience a period of anestrus when reproductive activity ceases. e. Psuedo-pregnancy occurs in non-pregnant bitch because of increases in prolactin. Menstrual Cycle in Human Females (Figure 6) (Concept Tutor on Menstrual Cycles) Estrus, commonly known as the 'heat' period, is a distinct phase in the estrous cycle of most female non-primate mammals. Called also estruation, estrum, and heat. adj. The meaning of ESTRUS is a regularly recurrent state of sexual receptivity during which the female of most mammals will accept the male and is capable of conceiving : heat; also : a single occurrence of this state. Menstrual Cycle in Human Females (Figure 6) (Concept Tutor on Menstrual Cycles) the recurrent, restricted period of sexual receptivity in female mammals other than human females, marked by intense sexual urge. zwfw, b5v8, nlug, x9cv, 9fnw, lcqbi, nmfaz, nu38he, 4q6ghu, bbcfn,