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Related to estrus induction: Oestrus


(US), estrus, estrum
a regularly occurring period of sexual receptivity in most female mammals, except humans, during which ovulation occurs and copulation can take place; heat


The period in mammals during which the female ovulates and is receptive to mating. It is commonly referred to as rut or heat. From one estrus period to the next there occurs a series of changes, particularly in the ovary, uterus, and vagina, termed the estrous cycle. With reference to the ovary, the cycle can be divided into a follicular phase, during which the Graafian follicles are ripening, and a luteal phase, during which the corpora lutea develop in the ovulated follicles. During these two phases, mainly estrogen and progesterone, respectively, are secreted, and these hormones control the uterine and vaginal changes. The beginning of the follicular phase is termed proestrus, and the luteal phase metestrus. Following the latter, there is a period of relatively little change, termed diestrus. In species in which the latter is prolonged, it is termed anestrus. See Estrogen, Reproduction (animal)



(also heat or rut), a stage in the sex and reproductive cycle, or period of sexual activity, in female mammals. Estrus recurs regularly before coitus at intervals characteristic for each species of animal—several days, weeks, or months. During estrus the mating instinct is aroused, and in most mammals ovulation occurs at the end of estrus. In polyestrous animals, estrus recurs periodically throughout the year. In mice and rats, for example, it occurs every four to six days; in guinea pigs, every 18 days; and in cows, every 21 days. In monestrous animals, it occurs once or twice a year, as in dogs and foxes. During estrus, morphological changes occur in the vagina and uterus; they are especially marked in such rodents as mice, rats, and guinea pigs.


The period in female mammals during which ovulation occurs and the animal is receptive to mating.
References in periodicals archive ?
TABLA I EFECTO DE LA DOSIS DE eCG SOBRE LA INDUCCION DEL CELO EN CABRAS TRATADAS CON MEDROXIPROGESTERONA/EFFECT OF DOSAGE OF eCG ON ESTRUS INDUCTION IN GOATS TREATED WITH MEDROXYPROGESTERONE Grupo n Tasa de celo Intervalo al Duracion del (%) celo (h) celo (h) GC 11 9/11 (81,8) 42,20 [+ o -] 42,14 [+ o -] 3,54 (b) 4,15 G250 10 10/10 (100) 40,65 [+ o -] 39,94 [+ o -] 3,27 (b) 3,81 G500 11 11/11 (100) 32,54 [+ o -] 42,14 [+ o -] 3,00 (a) 4,15 Valores con letras diferentes dentro de la misma columna difieren (P<0,05).
Bretzlaff and Madrid (1989) used a 3mg treatment and found an estrus induction of 97%, similar to the present findings.
Comparison of estrus induction and subsequent fertility with two different intravaginal devices in ewes during the non-breeding season.