(redirected from estrus detection)
Also found in: Dictionary, Thesaurus, Medical.


(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
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005


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)

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.



(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 Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.


The period in female mammals during which ovulation occurs and the animal is receptive to mating.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
In this paper, we present a vision-based cattle monitoring system for estrus detection as shown in Fig.
In particular, for the mounting action (the main action to be recognized for estrus detection), the true positive rate became 0.89, whereas both false positive and false negative were relatively small.
In the buserelin protocol, estrus detection is recommended to determine females to be subjected to hormone administration and insemination, as suggested by MARTINAT-BOTTE et al.
Chagunda, "On the Use of Physical Activity Monitoring for Estrus Detection in Dairy Cows," J.
Causes influencing AI including the number and motility of spermatozoa estrus detection and timing of AI as well as the animals' physical condition can serve to explain the difference.
Also, this finding may explain the differences in pregnancy rates observed after the timed AI at 54h after the device removal in ewes without estrus detection in the CIDR group (3 of 4) in comparison with the OB group (1 of 4).
The weaning-to-estrus interval is directly related to lactation period (lactation length, nutritional and feeding strategies, parity, litter number, weight and backfat thickness change), facilities, genetics and season (Koketsu et al., 1996; Zak et al., 1997; Boyd et al., 2002), as well as estrus detection and reproductive management.
In order the estrus detection, the cows were accompanied by teaser bulls in a 25:1 ratio and watched four times a day at cement pens and pasture area.
In order to calculate the wean-to-estrus interval, the beginning of the estrus period was characterized as the midpoint between the time of the first observed positive response to back pressure (immobilization reflex) and the previous period of estrus detection. The end of estrus was the midpoint between the time when a negative response to back pressure was first identified and the previous period of estrus detection.
Artificial insemination systems within two days of estrus detection or at fixed time for suckled beef cows
As the signs of estrus in buffaloes are less obvious than in cattle, the estrus detection accuracy is one of the major problems limiting the use of A.I.
Several factors have been suggested to be responsible for reduced conception rate including management practices, genetics, diseases, physiological disturbances, anatomical defects, feeding practices, estrus detection errors, embryonic mortality (Dekruif, 1978; Roussel et al., 1988; Wathes, 1992; Jainudeen and Hafez, 1993; Heuwieser et al., 1997), and heat stress (Badinga et al., 1985).