Metoestrus and dioestrus or pseudopregnancy comprise the luteal phase of the cycle. It should be noted therefore that there are no marked qualitative difference between dioestrus and pseudopregnancy, the latter representing a prolonged dioestrus.
What is the difference between metoestrus and dioestrus?
Metoestrus and dioestrus or pseudopregnancy comprise the luteal phase of the cycle. It should be noted therefore that there are no marked qualitative difference between dioestrus and pseudopregnancy, the latter representing a prolonged dioestrus.
What is diestrus?
Endocrinologically, by definition, diestrus is the phase of the cycle dominated by P4 secretion. Behaviorally, diestrus starts with the end of “standing heat”.
What is the difference between estrous diestrus and proestrus?
Estrous Diestrus - Vagina has a small opening and the tissues are bluish-purple in color and very moist. Proestrus - Vagina is gaping and the tissues are reddish-pink and moist. Numerous longitudinal folds or striations are visible on both the dorsal and ventral lips.
What is the difference between metestrus-1 and proestrus?
Proestrus - Vagina is gaping and the tissues are reddish-pink and moist. Numerous longitudinal folds or striations are visible on both the dorsal and ventral lips. Estrus - Vaginal signs are similar to proestrus, but the tissues are lighter pink and less moist, and the striations are more pronounced. Metestrus-1 - Vaginal tissues are pale and dry.
What happens Metestrus?
Estrus is followed by a 3 to 4 day period referred to as metestrus. During this period the corpus luteum develops under the influence of LH and starts to produce increasing amounts of progesterone. The period between metestrus and the beginning of the regression of the corpus luteum is referred to as diestrus.
What is the Metestrus stage?
The metestrus phase of the estrous cycle follows as the CL grows, fills the ruptured follicle cavity of the CH, and increases its synthesis of progesterone.
What is estrus and Anestrus?
Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency depending on the species.
What are the 4 stages of estrus?
The estrous cycle has four phases, namely proestrus, estrus, metestrus and diestrus and lasts for 4 to 5 days [4] (Table 1).
What is a Diestrus?
dioestrus in British English or US diestrus (daɪˈiːstrəs ) noun. a period of sexual inactivity between periods of oestrus in animals that have several oestrous cycles in one breeding season.
What is Metestrus in cattle?
Metestrus is the three to four days after estrus, and diestrus is the 12 to 15 days in the middle of the cycle. During proestrus, the pituitary gland of the brain secretes the follicle stimulating hormone (FSH) that causes the ovary to develop follicles.
What is Polyestrus?
Definition of polyestrous : having more than one period of estrus in a year.
What is Monoestrous?
Definition of monestrous : experiencing estrus once each year or breeding season.
What is anestrus in animals?
Anestrous sows are animals that fail to return to estrus following weaning. Ovaries from these sows have small follicles (less than 5 mm in diameter), well-regressed corpora albicantia, and no corpora lutea (Fig. 99-6). As previously mentioned, ovarian changes are minimal during lactation.
Can a dog get pregnant during Diestrus?
Clarifying the term “in heat” But these three symptoms are present during the proestrus, estrus, and diestrus stages of a dog's reproductive cycle — and she can get pregnant only during estrus.
What is the difference between estrous and menstrual cycle?
Estrous cycles are named for the cyclic appearance of behavioral sexual activity (estrus) that occurs in all mammals except for higher primates. Menstrual cycles, which occur only in primates, are named for the regular appearance of menses due to the shedding of the endometrial lining of the uterus.
What animals are Monoestrous?
Wolves, bears,foxes are having the monoestrous cycle. Deer, goats, sheep are having the polyestrous cycle.
What is the characteristic marker of diestrus?
Increased numbers of atretic follicles are also seen during diestrus. Newly formed corpora lutea from previous ovulation that attains the maximum size is the characteristic marker of diestrus.
What happens to the endometrial epithelium during metestrus?
During metestrus the endometrial degeneration is continued which reduces the height of the endometrial epithelium, but there is a return of mitotic activity and variable infiltration of leukocytes, so both are seen together.
What is the Estrus cycle of rats?
Estrus cycle of rats became irregular with prolonged estrus and metestrus phases, and reduced diestrus and proestrus phases after the oral administration of petroleum ether, benzene, chloroform, and alcohol extracts of the seeds of Momordica charantia (Cucurbitaceae) at a dose level of 25 mg/100 g body weight.
What is the estrous cycle?
The estrous cycle (derived from Latin oestrus; "frenzy", originally from Greek οἶστρος, oîstros; "gadfly") is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females.
When do estrous cycles start?
Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency depending on the species.
What is the difference between oestrous and menstrual cycles?
One difference is that animals that have oestrous cycles resorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead. Another difference is sexual activity.
How long is the oestrous cycle of buffalo?
Buffalo have an oestrous cycle of about 22 to 24 days. Buffalo are known for difficult eostrus detection. This is one major reason for being less productive than cattle. During four phases of its oestrous cycle, mean weight of corpus luteum has been found to be 1.23±0.22g (metoestrus), 3.15±0.10g (early dioestrus), 2.25±0.32g (late dioestrus), and 1.89±0.31g (pro-oestrus/oestrus), respectively. The plasma progesterone concentration was 1.68±0.37, 4.29±0.22, 3.89±0.33, and 0.34±0.14 ng/ml while mean vascular density (mean number of vessels/10 microscopic fields at 400x) in corpus luteum was 6.33±0.99, 18.00±0.86, 11.50±0.76, and 2.83±0.60 during the metestrus, early diestrus, late diestrus and proestrus/estrus, respectively.
What is the spelling of "estrus"?
In British and most Commonwealth English, the spelling is oestrus or (rarely) œstrus. In all English spellings, the noun ends in -us and the adjective in -ous. Thus in North American English, a mammal may be described as "in estrus" when it is in that particular part of the estrous cycle .
How long does a cat's oestrous cycle last?
Even within species significant variability can be observed, thus cats may undergo an oestrous cycle of 3 to 7 weeks. Domestication can affect oestrous cycles due to changes in the environment. For most species, vaginal smear cytology may be used in order to identify oestrous cycle phases and durations.
What is the term for the regression of the corpus luteum?
In the absence of pregnancy the diestrus phase (also termed pseudo-pregnancy) terminates with the regression of the corpus luteum. The lining in the uterus is not shed, but is reorganized for the next cycle. Other spellings include metoestrus, metestrum, metoestrum, dioestrus, diestrum, and dioestrum .
How long is the estrous cycle?
In rodents, there are four phases in the estrous cycle, and the average cycle length is 4–5 days. In metestrus (day 1), progesterone and estradiol circulate at relatively low levels. The following day (day 2), diestrus ensues, and early on in this postovulation phase, progesterone increases sharply and then drops quickly by the end of day (Butcher et al., 1974 ). At ∼1200 h on day 3, proestrus is initiated by a significant surge in estradiol levels. This marked increase in estradiol causes a rapid peak of LH and FSH between 1600 and 1800 h as well as an increased progesterone secretion. Finally, in estrus, ovulation occurs and all hormones return to baseline, save for a temporary peak in estradiol in the evening of estrus on day 4 ( Butcher et al., 1974 ).
What is the Estrus cycle of rats?
Estrus cycle of rats became irregular with prolonged estrus and metestrus phases, and reduced diestrus and proestrus phases after the oral administration of petroleum ether, benzene, chloroform, and alcohol extracts of the seeds of Momordica charantia (Cucurbitaceae) at a dose level of 25 mg/100 g body weight.
How often do dogs have anestrus?
In monestrous animals the luteal phase is followed by anestrus of at least 1–2 months, prior to the follicular phase of the next cycle. In some breeds, such as the basenji and the Tibetan mastiff, estrus usually occurs only once a year.
What is the name of the short interval of quiescence in pseudopregnancy?
In some species, (e.g. rat and mouse) oestrus is succeeded by only a short interval of quiescence, termed dioestrus.
Difference Between Oestrus Cycle and Menstrual Cycle
The key difference between Menstrual and Oestrous Cycles is that Menstrual Flow occurs in primates such as monkeys, apes, and humans, in which an unfertilized ovum along with a ruptured uterine epithelium discharges about 50-100 ml of blood and some mucus through the vaginal orifice and is called menstrual flow, whereas the Oestrous Cycle, in which a female becomes sexually responsive only during a specific season, is referred to as the "hot period" because there is no outflow from the vaginal canal and the endometrium is reabsorbed..
Different Phases of Oestrus Cycle
There are around four phases of the Oestrus Cycle they are as follows:
Variability of Oestrus Cycle
Oestrous Cycle variability varies by species, however, smaller animals have more frequent cycles. Even within species, there is a lot of variation, thus cats can have an Oestrous Cycle that lasts anywhere from 3 to 7 weeks. Because of changes in the environment, domestication can affect Oestrous Cycles.
Things to Remember
It occurs in non-primates such as sheep, rats, cows, deer, dogs and tigers etc.
Sample Questions
Answer- The Oestrous Cycle is a cyclical variation in the reproductive phase of non-primate animals. The Oestrous Cycle is a series of cyclical changes that occur during the breeding process.
How long does the estrous cycle last?
The estrous cycle has four phases, namely proestrus, estrus, metestrus and diestrus and lasts for 4 to 5 days [4] (Table (Table1).1).
What is the origin of the word "estrus"?
The word “estrus” was first used by Heape [13]. This is a Latin adaptation of the Greek word “oistros” which means “sexual season”, “gadfly”, “frenzy”, “sting” or “madness” [14]. Heape further named and defined the phases of the mammalian estrous cycle into proestrus, metestrus, diestrus and anestrus.
What are the phases of the menstrual cycle?
On the other hand, in humans, there are three phases of the menstrual cycle; the menstrual, proliferative (follicular), and secretory (luteal) phases. This cycle begins at puberty.
Is fatty acid in urine higher in estrus?
The concentration of fatty acids in the urine is also very higher in estrus. Urine carbohydrate level is similar throughout the estrous cycle [24]. Like the vaginal wall impedance, there is no report of standard values for urine biochemical at each phase of the estrous cycle for commonly used laboratory animals.
Do estrus animals have higher vaginal impedance?
Animals in estrus have higher vaginal impedance than those in non-estrus phase. Jaramillo et al. [21] revealed that pairing of a female with male animals based on vaginal wall impedance resulted in higher rates of confirmed mating as well as pregnancy when compared to pairing based on the vaginal smear.
What is the role of disintegrin and metalloproteinase in the oestrous cycle?
a disintegrin and metalloproteinase - (ADAM) a large family (-8, -9, -10, -12, -15 and -17) of secreted proteins suggested to be involved in remodelling mouse uterine tissue during the oestrous cycle.
Which is the most accurate method of identifying the stage of estrous?
When all 4 stages (proestrus, estrus, metestrus, and diestrus) need to be identified, vaginal cytology is regarded as the most accurate method. An identification tool is presented to aid the user in determining the stage of estrous when using vaginal cytology.
How do mice become estrus?
Whitten Effect - female mice either singly or housed together (in groups) can be induced into estrus by exposure to male mouse urine or their dirty bedding. The estrous cycle is applicable to many different species, not just the mouse reproductive cycle.
What are some examples of polyestrus?
Rats and mice are examples of polyestrus mammals (as are cats which are seasonally polyoestrus). Monestrus forms (most wild animals - foxes, bears, wolves etc.) complete a single estrous cycle annually. In the wild, rats and mice probably suspend the cycle for a period during the winter; the reproductive organs are in a state of quiescence, ...
Where can stromal decidualization be induced?
Stromal decidualization can also be induced experimentally in the hormonally prepared uterus in response to stimuli other than the embryo. ... This chapter describes the routine laboratory methodologies to study the events of early pregnancy, with special emphasis on the implantation process in mice.".
Do estrus cells retain nuclei?
In early estrus these cells retain their nuclei, but in later stages no nuclei visible and the cells are irregular, flat, cornified plates. The skin around the vaginal orifice becomes swollen. Contains hundreds of large cornified cells (squames) with degenerate nuclei.
Introduction
Estrous Cycle Stages
- The descriptions below refer to the "typical" mammalian cycle. 1. proestrus - estrus - metestrus - diestrus
Rat Estrous Cycle
- One of the best characterised polyestrous reproductive cycles, though different species of rats may differ in reproduction. In general, puberty occurs at 6-8 weeks when the estrous cycle commences each cycle is 4-5 days. The estrous cycle is polyestrous, more than one estrous cycle during a specific yearly time, with an estrous period of approximately 12 hours. See the review o…
Pig Estrous Cycle
- The feedback systems between the ovaries, uterus, hypothalamus and pituitary gland govern a cycle of events that takes 18-21 days. If conception occurs this cyclic pattern is interrupted and pregnancy is maintained for approximately 114 days. Removal of the sucking stimulus at weaning triggers a new sequence of events. 1. Links: pig | PubMed- pig estrous cycle
Dog Estrous Cycle
- Proestrus(9 days) - Precedes estrus, estradiol concentration increases as ovarian follicules mature and the uterus enlarges. The vaginal epithelium proliferates accompanied by diapedesis of erythro...
Bovine Estrous Cycle
- Specific hormone concentrations are not shown in the above graph, only the relative hormone levels at different times during the cycle. 1. Links: cow
Historic
- 1937 - Etymology and pronunciation of the word "oestrus" and its derivatives This word seems to offer more difficulties as to pronunciation and spelling than any other technical word in biology. Derived originally from the Greek oloxpos, signifying the gadfly, and taken over into Latin as oestrus, the word came secondarily to mean frenzy or strong desire. The Latin derivative is prop…
References
- Reviews
Westwood FR. (2008). The female rat reproductive cycle: a practical histological guide to staging. Toxicol Pathol , 36, 375-84. PMID: 18441260 DOI. Goldman JM, Murr AS & Cooper RL. (2007). The rodent estrous cycle: characterization of vaginal cytology and its utility in toxicological studies. … - Articles
Caligioni CS. (2009). Assessing reproductive status/stages in mice. Curr Protoc Neurosci , Appendix 4, Appendix 4I. PMID: 19575469 DOI. Hubscher CH, Brooks DL & Johnson JR. (2005). A quantitative method for assessing stages of the rat estrous cycle. Biotech Histochem , 80, 79-87…
External Links
- External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource…
Overview
The estrous cycle (from Latin oestrus 'frenzy', originally from Ancient Greek οἶστρος (oîstros) 'gadfly') is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian females. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phases, otherwise known as "rest" phases, or by pregnancies. Typically, estrous cycles repeat until death. These cycles are widely variable in duration and frequency dep…
Specific species
The female cat in heat has an estrus of 14 to 21 days and is generally characterized as an induced ovulator, since coitus induces ovulation. However, various incidents of spontaneous ovulation have been documented in the domestic cat and various non-domestic species. Without ovulation, she may enter interestrus, which is the combined stages of diestrus and anestrus, before reentering estrus. With the induction of ovulation, the female becomes pregnant or undergoes a …
Differences from the menstrual cycle
Mammals share the same reproductive system, including the regulatory hypothalamic system that produces gonadotropin-releasing hormone in pulses, the pituitary gland that secretes follicle-stimulating hormone and luteinizing hormone, and the ovary itself that releases sex hormones, including estrogens and progesterone.
However, species vary significantly in the detailed functioning. One difference is that animals th…
Etymology and nomenclature
Estrus is derived via Latin oestrus ('frenzy', 'gadfly'), from Greek οἶστρος oîstros (literally 'gadfly', more figuratively 'frenzy', 'madness', among other meanings like 'breeze'). Specifically, this refers to the gadfly in Ancient Greek mythology that Hera sent to torment Io, who had been won in her heifer form by Zeus. Euripides used oestrus to indicate 'frenzy', and to describe madness. Homer used the word to describe panic. Plato also used it to refer to an irrational drive and to describe the soul "dri…
Four phases
A four-phase terminology is used in reference to animals with estrous cycles.
One or several follicles of the ovary start to grow. Their number is species-specific. Typically this phase can last as little as one day or as long as three weeks, depending on the species. Under the influence of estrogen, the lining of the uterus (endometrium) starts to develop. Some animals may experience vaginal secretions that could be bloody. The female is not yet sexually receptive…
Cycle variability
Estrous cycle variability differs among species, but cycles are typically more frequent in smaller animals. Even within species significant variability can be observed, thus cats may undergo an estrous cycle of 3 to 7 weeks. Domestication can affect estrous cycles due to changes in the environment. For most species, vaginal smear cytology may be used in order to identify estrous cycle phases and durations.
Frequency
Some species, such as cats, cows and domestic pigs, are polyestrous, meaning that they can go into heat several times per year. Seasonally polyestrous animals or seasonal breeders have more than one estrous cycle during a specific time of the year and can be divided into short-day and long-day breeders:
• Short-day breeders, such as sheep, goats, deer and elk are sexually active in fall or winter.
See also
• Mating system
• Musth
• Neutering
• Progesterone-releasing intravaginal device
• Reproductive cycle